diff --git a/.project-docs/30-worklog/tasks/20260823-pi-renderer-store-b7e2c4a1.md b/.project-docs/30-worklog/tasks/20260823-pi-renderer-store-b7e2c4a1.md
new file mode 100644
index 0000000..2146f3e
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+++ b/.project-docs/30-worklog/tasks/20260823-pi-renderer-store-b7e2c4a1.md
@@ -0,0 +1,158 @@
+# Task: Implement PI-110 Renderer Snapshot Patch Store
+
+## Identity
+
+- Task ID: 20260823-pi-renderer-store-b7e2c4a1
+- Mode: Feature
+- Branch: codex/20260823-pi-renderer-store-b7e2c4a1-pi-renderer-store
+- Worktree: D:\Datas\OthersProjects\makelore-pi-renderer-store-b7e2c4a1
+- Base commit: a0722574f3b36cb73ec8833787711e6bef1c5c54
+- Owner: codex-root
+- Status: In Progress
+
+## Scope
+
+- Implement PI-110's vendor-neutral Renderer facade and one Zustand store keyed
+  by stable Makelore `conversationId`.
+- Consume the shared PI-010 Snapshot/Patch reducer for snapshot-first SSE,
+  stale-generation discard, target-only gap recovery, and reconnect.
+- Own per-Conversation snapshot/run/error/queue/model/draft/unread/cursor plus
+  optimistic prompt request state and fine-grained selectors.
+- Add focused facade/store/SSE/render-count tests. Do not migrate Chat UI,
+  feature-complete controls, or remove the old OpenCode store in this ticket.
+
+## Intent And Constraints
+
+- Base is the planner-approved PI-100 cumulative HEAD `a072257`; the exact and
+  sole Ready Frontier is `{PI-110}`.
+- Renderer access goes only through `src/lib/host-api.ts`; the SSE facade must
+  initialize the cached Host token/base before constructing EventSource.
+- Reuse the PI-010 contract/reducer as the single product normalization seam.
+  The first real Renderer consumer exposed that its Electron-only source
+  location requires unavailable composite-project declarations in a clean
+  worktree, so the canonical modules now live in `shared/` and Electron keeps
+  thin re-exports. Do not duplicate Pi/OpenCode event mapping or import vendor
+  types, paths, wire enums, credentials, or raw diagnostics.
+- A generation/sequence gap invalidates and reloads only its target
+  Conversation. Old generations are ignored and accepted prompts are never
+  replayed because an event stream reconnects.
+- Optimistic user identity is stable across durable reconciliation by
+  `clientRequestId`. Definite rejection and uncertain acceptance retain enough
+  request/draft/attachment state for explicit UI recovery; neither path
+  silently resends.
+- Store updates replace only the target Conversation entry. Timeline selectors
+  for the selected Conversation must not rerender when a hidden Conversation
+  streams; hidden/sidebar consumers use lightweight summaries.
+- PI-120 owns Composer and timeline UI; PI-130 owns model/thinking/queue/
+  compaction/interaction/subagent/changes UI; PI-140 owns old OpenCode removal.
+- Real Provider remains Explicitly Waived / Accepted Risk with
+  `realTurnVerified=false`; macOS remains deferred to mandatory PI-150. Neither
+  is Pass evidence. No subagents are authorized.
+
+## Project Context Loaded
+
+- Task identity: `20260823-pi-renderer-store-b7e2c4a1`, feature mode, isolated
+  branch/worktree above, base `a0722574f3b36cb73ec8833787711e6bef1c5c54`.
+- Concurrent Task Gate passed. The only semantically adjacent planning task,
+  `20260820-partner-create-model-parity-c83d`, still has no defined scope or
+  owned files. The canonical main integration task is Blocked and is not a
+  write target. Other active tasks concern unrelated Canvas/Robot/Learning or
+  review scopes.
+- Planning Gate inputs read: memory index, project positioning/success fields,
+  current state, decision/system/architecture/domain documents, evidence/
+  reflection/commitment/stale indexes, PI-010 and PI-100 records, and the exact
+  PI-110 ticket plus relevant Spec sections.
+- The canonical project-positioning fields remain placeholders; repository
+  guidance and the planner-owned Pi Spec/ticket are authoritative here.
+- Confirmed seams: vendor-neutral contracts and strict reducer in
+  `electron/coding-runtime`, snapshot-first `/api/coding/events`, target GET
+  snapshot, `hostApiFetch`, `ensureHostApiToken`, and Zustand selector patterns.
+- No accepted ADR changes product positioning or conflicts with this task.
+  Existing real OpenCode/provider commitments remain historical and do not
+  authorize a compatibility store or runtime fallback.
+- Gate result: Passed.
+
+## Plan
+
+1. Add a Renderer-owned type surface and minimal typed `/api/coding` facade for
+   target snapshot, prompt acceptance, and initialized global/target SSE.
+2. Implement a dependency-injectable Zustand store that keeps reducer state,
+   summary, draft, unread, request lifecycle, loading/recovery and errors per
+   Conversation while owning selection and one global event stream.
+3. Route snapshot and ordered patch events through the shared reducer; ignore
+   stale generation, reload only a gapped target, and never replay mutations on
+   reconnect.
+4. Add optimistic user-node/draft/attachment reconciliation and granular
+   selectors that preserve unrelated Conversation object identity.
+5. Add facade, two-Conversation SSE, gap/reconnect, optimistic failure, vendor
+   boundary and render-count regressions; then run focused/full verification,
+   build, documentation gates, and planner review.
+
+## Outcome
+
+- Added a Renderer-owned product type surface and minimal typed Host facade for
+  target snapshots, prompt acceptance, and EventSource creation. EventSource
+  construction first hydrates the cached Host token/base, including a cold
+  Renderer process.
+- Added one dependency-injectable vanilla Zustand store with React selectors.
+  Each Conversation owns its reducer snapshot/cursor, load and target error,
+  unread state, lightweight summary, draft revision/attachments, and prompt
+  request lifecycle. Store updates preserve unrelated Conversation identity.
+- Added snapshot-first SSE ingestion, native reconnect state, stale-generation
+  discard, per-target sequence/generation-gap recovery, load single-flight,
+  and connection-generation protection. Reconnect never replays a prompt and
+  an obsolete connection flight cannot clear a newer one.
+- Added optimistic user nodes keyed by `clientRequestId`. Durable upsert keeps
+  the optimistic UI node id; definite rejection restores an untouched draft
+  and marks the node failed; uncertain delivery restores the draft while
+  retaining the request/node for explicit reconciliation without resend.
+- Promoted the existing product-neutral PI-010 contracts, reducer, product
+  detail validator, and subagent detail validator to `shared/`. Existing
+  Electron paths are compatibility-free source re-exports of the same
+  functions, so Main, Renderer, fixtures, and tests cannot drift into separate
+  reducer implementations.
+- Added facade/store tests for two interleaved Conversations, target-only gap
+  recovery, stale generations, native reconnect, connection-flight ABA,
+  optimistic accepted/rejected/uncertain outcomes, attachment restoration,
+  vendor-neutral source boundaries, shared reducer identity, and render-count/
+  summary identity under hidden streaming.
+- PI-120/130/140 boundaries remain unchanged. No Chat page or legacy OpenCode
+  store consumer was changed by PI-110.
+
+## Verification
+
+- `pnpm exec vitest run tests/unit/coding-conversations-facade.test.ts tests/unit/coding-conversations-store.test.tsx`:
+  2 files / 12 tests passed.
+- `pnpm exec vitest run` for the two PI-110 tests plus PI-010 contracts,
+  coding core routes, event projector, Conversation runtime, product tools,
+  and subagent suites: 8 files / 75 tests passed.
+- `pnpm run typecheck`: passed after the shared product seam removed the clean
+  Renderer -> composite Electron declaration dependency.
+- `pnpm run lint:check`: passed with zero errors and the same six unrelated
+  Renderer warnings in `ExecutionGraphCard.tsx`, Home, and Makelore.
+- `pnpm test`: 211 files / 2275 passed / 2 skipped (2277 total).
+- `pnpm run build:vite`: Renderer, Electron Main, Preload, and release utility
+  production builds passed; existing dynamic-import and large-chunk warnings
+  remain.
+- Electron E2E is not applicable yet: PI-110 intentionally exposes no page or
+  user-visible interaction. The real Chat/Composer binding and its E2E belong
+  to PI-120; the render-count store acceptance is covered directly here.
+- Real Provider remains Explicitly Waived / Accepted Risk with
+  `realTurnVerified=false`. macOS x64/arm64 remains deferred to mandatory
+  PI-150. Neither is recorded as Pass.
+
+## Follow-ups
+
+- PI-120 should bind the Composer/timeline to this store without restoring any
+  read from `src/stores/opencode.ts`.
+
+## Promotion Candidates
+
+- Type: Architecture. Proposal: keep Makelore-owned Conversation contracts and
+  the strict Snapshot/Patch reducer in `shared/`, with Main and Renderer
+  importing/re-exporting that single implementation rather than depending on
+  Electron composite build artifacts or copying normalization logic. Evidence:
+  clean `pnpm run typecheck`, shared/Main function identity regression, 8-file
+  75-test impacted suite, and full 211-file unit/build verification. Future
+  impact: PI-120/130 can consume product DTOs without vendor/Main imports; any
+  contract amendment must retain Main/Renderer reducer equivalence.
diff --git a/electron/coding-runtime/contracts.ts b/electron/coding-runtime/contracts.ts
index 49cb690..2ba4ce0 100644
--- a/electron/coding-runtime/contracts.ts
+++ b/electron/coding-runtime/contracts.ts
@@ -1,435 +1 @@
-export type ConversationThinkingLevel = 'off' | 'minimal' | 'low' | 'medium' | 'high';
-
-export interface ProductModelRef {
-  accountId: string;
-  modelId: string;
-  thinkingLevel: ConversationThinkingLevel;
-}
-
-export interface ConversationModelState {
-  model: ProductModelRef | null;
-  modelResolution: 'resolved' | 'required';
-}
-
-export interface PublicUsage {
-  inputTokens: number;
-  outputTokens: number;
-  cacheReadTokens?: number;
-  cacheWriteTokens?: number;
-}
-
-export type CodingRuntimeErrorCode =
-  | 'CODING_RUNTIME_START_FAILED'
-  | 'CODING_RUNTIME_READY_TIMEOUT'
-  | 'CODING_RUNTIME_PROTOCOL_ERROR'
-  | 'CODING_PROVIDER_AUTH_REQUIRED'
-  | 'CODING_MODEL_UNAVAILABLE'
-  | 'CODING_SESSION_UNREADABLE'
-  | 'CODING_STORAGE_WRITE_FAILED'
-  | 'CODING_REQUEST_UNCERTAIN'
-  | 'CODING_MIGRATION_MODEL_REQUIRED'
-  | 'CODING_CONVERSATION_NOT_FOUND';
-
-export interface CodingRuntimePublicError {
-  code: CodingRuntimeErrorCode;
-  message: string;
-  recoverable: boolean;
-}
-
-export type ConversationRunStatus =
-  | 'idle'
-  | 'preparing'
-  | 'queued'
-  | 'running'
-  | 'retrying'
-  | 'compacting'
-  | 'aborting'
-  | 'error';
-
-export type PromptMode = 'prompt' | 'steer' | 'follow-up';
-
-export interface ConversationRunState {
-  status: ConversationRunStatus;
-  runId?: string;
-  mode?: PromptMode;
-  startedAt?: number;
-  settledAt?: number;
-  terminalReason?: 'completed' | 'aborted' | 'failed';
-  retry?: {
-    attempt: number;
-    delayMs: number;
-  };
-  error?: CodingRuntimePublicError;
-}
-
-export interface ConversationQueueItem {
-  id: string;
-  clientRequestId: string;
-  mode: 'steer' | 'follow-up';
-  text: string;
-  attachmentIds: string[];
-}
-
-export interface ConversationQueueState {
-  items: ConversationQueueItem[];
-}
-
-export interface ConversationContextState {
-  usedTokens: number;
-  contextWindow: number;
-  outputLimit?: number;
-  compaction: 'idle' | 'running';
-  lastCompactionId?: string;
-  recalculating?: boolean;
-}
-
-export interface ConversationInteractionOption {
-  id: string;
-  label: string;
-  description?: string;
-}
-
-export interface ConversationInteraction {
-  id: string;
-  conversationId: string;
-  runId: string;
-  kind: 'select' | 'confirm' | 'input' | 'editor';
-  title: string;
-  message?: string;
-  options?: ConversationInteractionOption[];
-  status: 'pending' | 'answered' | 'rejected' | 'cancelled';
-}
-
-export interface PublicWorkerState {
-  status: 'stopped' | 'starting' | 'ready' | 'recovering' | 'error';
-  generation: number;
-  error?: CodingRuntimePublicError;
-}
-
-export type ConversationContentBlock =
-  | {
-    kind: 'text';
-    id: string;
-    text: string;
-    status: 'streaming' | 'complete';
-  }
-  | {
-    kind: 'thinking';
-    id: string;
-    text: string;
-    status: 'streaming' | 'complete';
-  }
-  | {
-    kind: 'image';
-    id: string;
-    attachmentId: string;
-    mime: string;
-  };
-
-export interface ConversationMessageNode {
-  kind: 'message';
-  id: string;
-  sourceEntryId?: string;
-  clientRequestId?: string;
-  role: 'user' | 'assistant';
-  status: 'optimistic' | 'streaming' | 'complete' | 'error' | 'aborted';
-  blocks: ConversationContentBlock[];
-  usage?: PublicUsage;
-  stopReason?: 'stop' | 'length' | 'tool-use' | 'error' | 'aborted';
-}
-
-export interface ChangedFileDetailsV1 {
-  schema: 'changed-file.v1';
-  paths: string[];
-}
-
-export interface TaskStateDetailsV1 {
-  schema: 'task-state.v1';
-  tasks: Array<{
-    id: string;
-    title: string;
-    status: 'pending' | 'running' | 'complete' | 'error';
-  }>;
-}
-
-export interface WriteLeaseDetailsV1 {
-  schema: 'write-lease.v1';
-  status: 'waiting' | 'held' | 'released';
-}
-
-export interface AgentBrowserDetailsV1 {
-  schema: 'agent-browser.v1';
-  action: 'open' | 'status' | 'close' | 'reset_profile' | 'navigate' | 'send_cdp' | 'read_events' | 'read_payload';
-  attachmentId?: string;
-  mime?: string;
-}
-
-export interface GameAssetsDetailsV1 {
-  schema: 'game-assets.v1';
-  invocationId: string;
-  candidateIds: string[];
-  status: 'pending' | 'resolved';
-  pendingAssetIds: string[];
-  approvedAssetIds: string[];
-  discardedAssetIds: string[];
-}
-
-export interface RuntimeContextDetailsV1 {
-  schema: 'runtime-context.v1';
-  skills: Array<{
-    id: string;
-    name: string;
-    description: string;
-    selected: boolean;
-  }>;
-  commands: Array<{
-    name: string;
-    title: string;
-    description: string;
-    source: 'makelore' | 'pi' | 'skill';
-    skillId?: string;
-  }>;
-}
-
-export interface SubagentDetailsV1 {
-  schema: 'subagent.v1';
-  dispatchId: string;
-  mode: 'single' | 'parallel' | 'chain';
-  tasks: Array<{
-    taskId: string;
-    agentId: string;
-    toolProfile: 'read-only' | 'coding';
-    status: 'queued' | 'running' | 'complete' | 'error' | 'aborted' | 'skipped';
-    summary?: string;
-    errorCode?: string;
-    usage?: PublicUsage;
-  }>;
-}
-
-export type KnownToolDetails =
-  | ChangedFileDetailsV1
-  | TaskStateDetailsV1
-  | WriteLeaseDetailsV1
-  | AgentBrowserDetailsV1
-  | GameAssetsDetailsV1
-  | RuntimeContextDetailsV1
-  | SubagentDetailsV1;
-
-export interface ConversationToolNode {
-  kind: 'tool';
-  id: string;
-  toolCallId: string;
-  toolName: string;
-  title: string;
-  inputText: string;
-  status: 'declared' | 'waiting' | 'running' | 'complete' | 'error' | 'aborted';
-  output: ConversationContentBlock[];
-  details?: KnownToolDetails;
-}
-
-export interface ConversationCompactionNode {
-  kind: 'compaction';
-  id: string;
-  runId: string;
-  source: 'manual' | 'automatic';
-  status: 'running' | 'complete' | 'error';
-  willRetry: boolean;
-  summary?: string;
-}
-
-export interface ConversationBoundaryNode {
-  kind: 'boundary';
-  id: string;
-  runId: string;
-  boundary: 'turn-start' | 'turn-end' | 'retry';
-  attempt?: number;
-  delayMs?: number;
-}
-
-export interface ConversationSubagentNode {
-  kind: 'subagent';
-  id: string;
-  runId: string;
-  details: SubagentDetailsV1;
-}
-
-export interface ConversationNoticeNode {
-  kind: 'notice';
-  id: string;
-  code: string;
-  level: 'info' | 'warning' | 'error';
-  message: string;
-}
-
-export type ConversationNode =
-  | ConversationMessageNode
-  | ConversationToolNode
-  | ConversationCompactionNode
-  | ConversationBoundaryNode
-  | ConversationSubagentNode
-  | ConversationNoticeNode;
-
-export interface ConversationSnapshot {
-  schemaVersion: 1;
-  conversation: {
-    id: string;
-    projectId: string;
-    agentId: string;
-    title: string;
-    model: ConversationModelState;
-  };
-  nodes: ConversationNode[];
-  run: ConversationRunState;
-  queue: ConversationQueueState;
-  context: ConversationContextState;
-  pendingInteractions: ConversationInteraction[];
-  worker: PublicWorkerState;
-  cursor: {
-    workerGeneration: number;
-    seq: number;
-    leafEntryId?: string;
-  };
-}
-
-export type ConversationPatch =
-  | { op: 'worker.state'; state: PublicWorkerState }
-  | { op: 'run.state'; run: ConversationRunState }
-  | { op: 'message.upsert'; node: ConversationMessageNode }
-  | { op: 'message.block-delta'; messageId: string; blockId: string; delta: string }
-  | { op: 'tool.upsert'; node: ConversationToolNode }
-  | { op: 'compaction.upsert'; node: ConversationCompactionNode }
-  | { op: 'boundary.upsert'; node: ConversationBoundaryNode }
-  | { op: 'subagent.upsert'; node: ConversationSubagentNode }
-  | { op: 'queue.replace'; queue: ConversationQueueState }
-  | { op: 'interaction.upsert'; interaction: ConversationInteraction }
-  | { op: 'interaction.remove'; interactionId: string }
-  | { op: 'context.replace'; context: ConversationContextState }
-  | { op: 'snapshot.invalidated'; reason: string };
-
-export interface ConversationPatchEnvelope {
-  conversationId: string;
-  workerGeneration: number;
-  runId?: string;
-  seq: number;
-  at: number;
-  patch: ConversationPatch;
-}
-
-export interface PrepareConversationInput {
-  conversationId: string;
-  projectId: string;
-  agentId: string;
-  title: string;
-  model: ConversationModelState;
-}
-
-export interface ConversationRuntimeState {
-  conversationId: string;
-  status: PublicWorkerState['status'];
-  workerGeneration: number;
-  error?: CodingRuntimePublicError;
-}
-
-export interface PromptConversationInput {
-  clientRequestId: string;
-  conversationId: string;
-  mode: PromptMode;
-  text: string;
-  attachments: Array<{ attachmentId: string }>;
-}
-
-export interface QueueMessageInput {
-  clientRequestId: string;
-  conversationId: string;
-  text: string;
-  attachments: Array<{ attachmentId: string }>;
-}
-
-export interface PromptAcceptance {
-  accepted: true;
-  conversationId: string;
-  clientRequestId: string;
-  runId: string;
-  mode: PromptMode;
-  queuePosition?: number;
-}
-
-export interface QueueAcceptance {
-  accepted: true;
-  conversationId: string;
-  clientRequestId: string;
-  mode: 'steer' | 'follow-up';
-  queuePosition: number;
-}
-
-export interface SetConversationModelInput {
-  conversationId: string;
-  accountId: string;
-  modelId: string;
-}
-
-export interface SetThinkingLevelInput {
-  conversationId: string;
-  thinkingLevel: ConversationThinkingLevel;
-}
-
-export interface ForkConversationInput {
-  sourceConversationId: string;
-  sourceEntryId?: string;
-  conversation: PrepareConversationInput;
-}
-
-export interface ForkResult {
-  conversationId: string;
-  snapshot: ConversationSnapshot;
-}
-
-export interface CodingRuntimeCommand {
-  name: string;
-  description?: string;
-}
-
-export type ConversationInteractionResponse =
-  | { interactionId: string; cancelled: true }
-  | { interactionId: string; optionId: string }
-  | { interactionId: string; confirmed: boolean }
-  | { interactionId: string; value: string };
-
-export interface CodingRuntimeDiagnostics {
-  revision: {
-    provider: number;
-    resources: number;
-  };
-  workers: Array<{
-    conversationId: string;
-    generation: number;
-    state: 'spawning' | 'ready' | 'queued' | 'running' | 'idle' | 'crashed';
-    stage: 'starting' | 'idle' | 'queued' | 'running' | 'failed';
-  }>;
-}
-
-export interface CodingConversationRuntime {
-  prepare(input: PrepareConversationInput): Promise<ConversationRuntimeState>;
-  getSnapshot(conversationId: string): Promise<ConversationSnapshot>;
-  prompt(input: PromptConversationInput): Promise<PromptAcceptance>;
-  steer(input: QueueMessageInput): Promise<QueueAcceptance>;
-  followUp(input: QueueMessageInput): Promise<QueueAcceptance>;
-  abort(conversationId: string): Promise<void>;
-  validateModel(model: ProductModelRef): Promise<ProductModelRef>;
-  setModel(input: SetConversationModelInput): Promise<ConversationModelState>;
-  setThinking(input: SetThinkingLevelInput): Promise<ConversationModelState>;
-  compact(conversationId: string): Promise<void>;
-  fork(input: ForkConversationInput): Promise<ForkResult>;
-  recover(conversationId: string): Promise<ConversationRuntimeState>;
-  dispose(conversationId: string): Promise<void>;
-  listCommands(conversationId: string): Promise<CodingRuntimeCommand[]>;
-  listInteractions(conversationId?: string): Promise<ConversationInteraction[]>;
-  respondInteraction(
-    conversationId: string,
-    response: ConversationInteractionResponse,
-  ): Promise<void>;
-  getDiagnostics(): CodingRuntimeDiagnostics;
-  markProviderStale(): void;
-  markResourcesStale(): void;
-  subscribe(listener: (patch: ConversationPatchEnvelope) => void): () => void;
-}
+export * from '../../shared/coding-conversation-contracts';
diff --git a/electron/coding-runtime/conversation-reducer.ts b/electron/coding-runtime/conversation-reducer.ts
index b04748c..f25f87f 100644
--- a/electron/coding-runtime/conversation-reducer.ts
+++ b/electron/coding-runtime/conversation-reducer.ts
@@ -1,554 +1 @@
-import type {
-  CodingRuntimePublicError,
-  ConversationContentBlock,
-  ConversationInteraction,
-  ConversationMessageNode,
-  ConversationNode,
-  ConversationPatch,
-  ConversationPatchEnvelope,
-  ConversationQueueState,
-  ConversationRunState,
-  ConversationSnapshot,
-  ConversationSubagentNode,
-  ConversationToolNode,
-  KnownToolDetails,
-  PublicWorkerState,
-} from './contracts';
-import { productToolDetails } from './product-tool-protocol';
-import { projectSubagentDetailsV1 } from './subagent-protocol';
-
-export type ConversationInvalidationCode =
-  | 'snapshot-required'
-  | 'unsupported-schema'
-  | 'malformed-snapshot'
-  | 'malformed-envelope'
-  | 'unknown-patch'
-  | 'generation-gap'
-  | 'sequence-gap'
-  | 'patch-target-missing'
-  | 'explicit-invalidation';
-
-export interface ConversationInvalidation {
-  code: ConversationInvalidationCode;
-  reason: string;
-  expectedGeneration?: number;
-  actualGeneration?: number;
-  expectedSeq?: number;
-  actualSeq?: number;
-}
-
-export interface ConversationReducerState {
-  snapshot: ConversationSnapshot | null;
-  invalidation: ConversationInvalidation | null;
-}
-
-const RUN_STATUSES = new Set([
-  'idle',
-  'preparing',
-  'queued',
-  'running',
-  'retrying',
-  'compacting',
-  'aborting',
-  'error',
-]);
-
-const WORKER_STATUSES = new Set(['stopped', 'starting', 'ready', 'recovering', 'error']);
-const ERROR_CODES = new Set([
-  'CODING_RUNTIME_START_FAILED',
-  'CODING_RUNTIME_READY_TIMEOUT',
-  'CODING_RUNTIME_PROTOCOL_ERROR',
-  'CODING_PROVIDER_AUTH_REQUIRED',
-  'CODING_MODEL_UNAVAILABLE',
-  'CODING_SESSION_UNREADABLE',
-  'CODING_STORAGE_WRITE_FAILED',
-  'CODING_REQUEST_UNCERTAIN',
-  'CODING_MIGRATION_MODEL_REQUIRED',
-  'CODING_CONVERSATION_NOT_FOUND',
-]);
-const PATCH_OPS = new Set([
-  'worker.state',
-  'run.state',
-  'message.upsert',
-  'message.block-delta',
-  'tool.upsert',
-  'compaction.upsert',
-  'boundary.upsert',
-  'subagent.upsert',
-  'queue.replace',
-  'interaction.upsert',
-  'interaction.remove',
-  'context.replace',
-  'snapshot.invalidated',
-]);
-
-function clone<T>(value: T): T {
-  return structuredClone(value);
-}
-
-function asRecord(value: unknown): Record<string, unknown> | null {
-  return value !== null && typeof value === 'object' && !Array.isArray(value)
-    ? value as Record<string, unknown>
-    : null;
-}
-
-function isNonEmptyString(value: unknown): value is string {
-  return typeof value === 'string' && value.length > 0;
-}
-
-function isNonNegativeInteger(value: unknown): value is number {
-  return Number.isInteger(value) && Number(value) >= 0;
-}
-
-function isOptionalNumber(value: unknown): boolean {
-  return value === undefined || typeof value === 'number';
-}
-
-function isPublicError(value: unknown): value is CodingRuntimePublicError {
-  const record = asRecord(value);
-  return record !== null
-    && ERROR_CODES.has(String(record.code))
-    && isNonEmptyString(record.message)
-    && typeof record.recoverable === 'boolean';
-}
-
-function isModelState(value: unknown): boolean {
-  const record = asRecord(value);
-  if (!record || !['resolved', 'required'].includes(String(record.modelResolution))) return false;
-  if (record.model === null) return record.modelResolution === 'required';
-  const model = asRecord(record.model);
-  return model !== null
-    && isNonEmptyString(model.accountId)
-    && isNonEmptyString(model.modelId)
-    && ['off', 'minimal', 'low', 'medium', 'high'].includes(String(model.thinkingLevel))
-    && record.modelResolution === 'resolved';
-}
-
-function isUsage(value: unknown): boolean {
-  const record = asRecord(value);
-  return record !== null
-    && typeof record.inputTokens === 'number'
-    && typeof record.outputTokens === 'number'
-    && isOptionalNumber(record.cacheReadTokens)
-    && isOptionalNumber(record.cacheWriteTokens);
-}
-
-function isContentBlock(value: unknown): value is ConversationContentBlock {
-  const record = asRecord(value);
-  if (!record || !isNonEmptyString(record.id) || !isNonEmptyString(record.kind)) return false;
-  if (record.kind === 'image') {
-    return isNonEmptyString(record.attachmentId) && isNonEmptyString(record.mime);
-  }
-  return (record.kind === 'text' || record.kind === 'thinking')
-    && typeof record.text === 'string'
-    && (record.status === 'streaming' || record.status === 'complete');
-}
-
-function isKnownToolDetails(value: unknown): value is KnownToolDetails {
-  const record = asRecord(value);
-  if (!record || !isNonEmptyString(record.schema)) return false;
-  if (productToolDetails(record)) return true;
-  if (record.schema === 'write-lease.v1') {
-    return record.status === 'waiting' || record.status === 'held' || record.status === 'released';
-  }
-  if (record.schema === 'subagent.v1') {
-    return projectSubagentDetailsV1(record) !== undefined;
-  }
-  return false;
-}
-
-function isMessageNode(value: unknown): value is ConversationMessageNode {
-  const record = asRecord(value);
-  return record !== null
-    && record.kind === 'message'
-    && isNonEmptyString(record.id)
-    && (record.role === 'user' || record.role === 'assistant')
-    && ['optimistic', 'streaming', 'complete', 'error', 'aborted'].includes(String(record.status))
-    && Array.isArray(record.blocks)
-    && record.blocks.every(isContentBlock)
-    && (record.usage === undefined || isUsage(record.usage));
-}
-
-function isToolNode(value: unknown): value is ConversationToolNode {
-  const record = asRecord(value);
-  return record !== null
-    && record.kind === 'tool'
-    && isNonEmptyString(record.id)
-    && isNonEmptyString(record.toolCallId)
-    && isNonEmptyString(record.toolName)
-    && typeof record.title === 'string'
-    && typeof record.inputText === 'string'
-    && ['declared', 'waiting', 'running', 'complete', 'error', 'aborted']
-      .includes(String(record.status))
-    && Array.isArray(record.output)
-    && record.output.every(isContentBlock)
-    && (record.details === undefined || isKnownToolDetails(record.details));
-}
-
-function isSubagentNode(value: unknown): value is ConversationSubagentNode {
-  const record = asRecord(value);
-  return record !== null
-    && record.kind === 'subagent'
-    && isNonEmptyString(record.id)
-    && isNonEmptyString(record.runId)
-    && isKnownToolDetails(record.details)
-    && record.details.schema === 'subagent.v1';
-}
-
-function isConversationNode(value: unknown): value is ConversationNode {
-  const record = asRecord(value);
-  if (!record || !isNonEmptyString(record.kind) || !isNonEmptyString(record.id)) return false;
-  if (record.kind === 'message') return isMessageNode(record);
-  if (record.kind === 'tool') return isToolNode(record);
-  if (record.kind === 'subagent') return isSubagentNode(record);
-  if (record.kind === 'compaction') {
-    return isNonEmptyString(record.runId)
-      && ['manual', 'automatic'].includes(String(record.source))
-      && ['running', 'complete', 'error'].includes(String(record.status))
-      && typeof record.willRetry === 'boolean';
-  }
-  if (record.kind === 'boundary') {
-    return isNonEmptyString(record.runId)
-      && ['turn-start', 'turn-end', 'retry'].includes(String(record.boundary));
-  }
-  if (record.kind === 'notice') {
-    return isNonEmptyString(record.code)
-      && ['info', 'warning', 'error'].includes(String(record.level))
-      && typeof record.message === 'string';
-  }
-  return false;
-}
-
-function isInteraction(value: unknown): value is ConversationInteraction {
-  const record = asRecord(value);
-  return record !== null
-    && isNonEmptyString(record.id)
-    && isNonEmptyString(record.conversationId)
-    && isNonEmptyString(record.runId)
-    && ['select', 'confirm', 'input', 'editor'].includes(String(record.kind))
-    && typeof record.title === 'string'
-    && ['pending', 'answered', 'rejected', 'cancelled'].includes(String(record.status));
-}
-
-function isRunState(value: unknown): value is ConversationRunState {
-  const record = asRecord(value);
-  return record !== null
-    && RUN_STATUSES.has(String(record.status))
-    && (record.error === undefined || isPublicError(record.error));
-}
-
-function isQueueState(value: unknown): value is ConversationQueueState {
-  const record = asRecord(value);
-  return record !== null && Array.isArray(record.items) && record.items.every((item) => {
-    const queueItem = asRecord(item);
-    return queueItem !== null
-      && isNonEmptyString(queueItem.id)
-      && isNonEmptyString(queueItem.clientRequestId)
-      && ['steer', 'follow-up'].includes(String(queueItem.mode))
-      && typeof queueItem.text === 'string'
-      && Array.isArray(queueItem.attachmentIds)
-      && queueItem.attachmentIds.every(isNonEmptyString);
-  });
-}
-
-function isWorkerState(value: unknown): value is PublicWorkerState {
-  const record = asRecord(value);
-  return record !== null
-    && WORKER_STATUSES.has(String(record.status))
-    && isNonNegativeInteger(record.generation)
-    && (record.error === undefined || isPublicError(record.error));
-}
-
-export function isConversationSnapshot(value: unknown): value is ConversationSnapshot {
-  const record = asRecord(value);
-  const conversation = asRecord(record?.conversation);
-  const cursor = asRecord(record?.cursor);
-  const context = asRecord(record?.context);
-  const worker = record?.worker;
-  return record !== null
-    && record.schemaVersion === 1
-    && conversation !== null
-    && isNonEmptyString(conversation.id)
-    && isNonEmptyString(conversation.projectId)
-    && isNonEmptyString(conversation.agentId)
-    && typeof conversation.title === 'string'
-    && isModelState(conversation.model)
-    && Array.isArray(record.nodes)
-    && record.nodes.every(isConversationNode)
-    && isRunState(record.run)
-    && isQueueState(record.queue)
-    && context !== null
-    && typeof context.usedTokens === 'number'
-    && typeof context.contextWindow === 'number'
-    && ['idle', 'running'].includes(String(context.compaction))
-    && (context.recalculating === undefined || typeof context.recalculating === 'boolean')
-    && Array.isArray(record.pendingInteractions)
-    && record.pendingInteractions.every(isInteraction)
-    && isWorkerState(worker)
-    && cursor !== null
-    && isNonNegativeInteger(cursor.workerGeneration)
-    && isNonNegativeInteger(cursor.seq)
-    && asRecord(worker)?.generation === cursor.workerGeneration;
-}
-
-function isPatch(value: unknown): value is ConversationPatch {
-  const record = asRecord(value);
-  if (!record || !PATCH_OPS.has(String(record.op))) return false;
-  switch (record.op) {
-    case 'worker.state':
-      return isWorkerState(record.state);
-    case 'run.state':
-      return isRunState(record.run);
-    case 'message.upsert':
-      return isMessageNode(record.node);
-    case 'message.block-delta':
-      return isNonEmptyString(record.messageId)
-        && isNonEmptyString(record.blockId)
-        && typeof record.delta === 'string';
-    case 'tool.upsert':
-      return isToolNode(record.node);
-    case 'compaction.upsert':
-      return isConversationNode(record.node) && record.node.kind === 'compaction';
-    case 'boundary.upsert':
-      return isConversationNode(record.node) && record.node.kind === 'boundary';
-    case 'subagent.upsert':
-      return isSubagentNode(record.node);
-    case 'queue.replace':
-      return isQueueState(record.queue);
-    case 'interaction.upsert':
-      return isInteraction(record.interaction);
-    case 'interaction.remove':
-      return isNonEmptyString(record.interactionId);
-    case 'context.replace': {
-      const context = asRecord(record.context);
-      return context !== null
-        && typeof context.usedTokens === 'number'
-        && typeof context.contextWindow === 'number'
-        && ['idle', 'running'].includes(String(context.compaction))
-        && (context.recalculating === undefined || typeof context.recalculating === 'boolean');
-    }
-    case 'snapshot.invalidated':
-      return isNonEmptyString(record.reason);
-    default:
-      return false;
-  }
-}
-
-function parseEnvelopeShell(value: unknown): Omit<ConversationPatchEnvelope, 'patch'> & { patch: unknown } | null {
-  const record = asRecord(value);
-  if (!record
-    || !isNonEmptyString(record.conversationId)
-    || !isNonNegativeInteger(record.workerGeneration)
-    || !isNonNegativeInteger(record.seq)
-    || typeof record.at !== 'number') {
-    return null;
-  }
-  return record as unknown as Omit<ConversationPatchEnvelope, 'patch'> & { patch: unknown };
-}
-
-function invalidate(
-  state: ConversationReducerState,
-  invalidation: ConversationInvalidation,
-): ConversationReducerState {
-  return { snapshot: state.snapshot, invalidation };
-}
-
-export function createConversationReducerState(snapshot?: unknown): ConversationReducerState {
-  if (snapshot === undefined) return { snapshot: null, invalidation: null };
-  return replaceConversationSnapshot({ snapshot: null, invalidation: null }, snapshot);
-}
-
-export function replaceConversationSnapshot(
-  state: ConversationReducerState,
-  snapshot: unknown,
-): ConversationReducerState {
-  const record = asRecord(snapshot);
-  if (record?.schemaVersion !== 1) {
-    return invalidate(state, {
-      code: 'unsupported-schema',
-      reason: 'Conversation snapshot schemaVersion must equal 1',
-    });
-  }
-  if (!isConversationSnapshot(snapshot)) {
-    return invalidate(state, {
-      code: 'malformed-snapshot',
-      reason: 'Conversation snapshot does not match the product contract',
-    });
-  }
-  return { snapshot: clone(snapshot), invalidation: null };
-}
-
-function upsertMessage(nodes: ConversationNode[], incoming: ConversationMessageNode): ConversationNode[] {
-  const index = nodes.findIndex((node) => node.kind === 'message' && (
-    node.id === incoming.id
-    || (incoming.sourceEntryId !== undefined && node.sourceEntryId === incoming.sourceEntryId)
-    || (incoming.clientRequestId !== undefined && node.clientRequestId === incoming.clientRequestId)
-  ));
-  if (index < 0) return [...nodes, clone(incoming)];
-  const existing = nodes[index] as ConversationMessageNode;
-  const next = [...nodes];
-  next[index] = { ...clone(incoming), id: existing.id };
-  return next;
-}
-
-function upsertTool(nodes: ConversationNode[], incoming: ConversationToolNode): ConversationNode[] {
-  const index = nodes.findIndex((node) => node.kind === 'tool' && (
-    node.id === incoming.id || node.toolCallId === incoming.toolCallId
-  ));
-  if (index < 0) return [...nodes, clone(incoming)];
-  const existing = nodes[index] as ConversationToolNode;
-  const next = [...nodes];
-  next[index] = { ...clone(incoming), id: existing.id };
-  return next;
-}
-
-function upsertById(nodes: ConversationNode[], incoming: ConversationNode): ConversationNode[] {
-  const index = nodes.findIndex((node) => node.kind === incoming.kind && node.id === incoming.id);
-  if (index < 0) return [...nodes, clone(incoming)];
-  const next = [...nodes];
-  next[index] = clone(incoming);
-  return next;
-}
-
-function applyPatch(
-  snapshot: ConversationSnapshot,
-  patch: ConversationPatch,
-): { snapshot: ConversationSnapshot } | { missingTarget: string } {
-  switch (patch.op) {
-    case 'worker.state':
-      return { snapshot: { ...snapshot, worker: clone(patch.state) } };
-    case 'run.state':
-      return { snapshot: { ...snapshot, run: clone(patch.run) } };
-    case 'message.upsert':
-      return { snapshot: { ...snapshot, nodes: upsertMessage(snapshot.nodes, patch.node) } };
-    case 'message.block-delta': {
-      const messageIndex = snapshot.nodes.findIndex(
-        (node) => node.kind === 'message' && node.id === patch.messageId,
-      );
-      if (messageIndex < 0) return { missingTarget: `message:${patch.messageId}` };
-      const message = snapshot.nodes[messageIndex] as ConversationMessageNode;
-      const blockIndex = message.blocks.findIndex((block) => block.id === patch.blockId);
-      if (blockIndex < 0) return { missingTarget: `block:${patch.blockId}` };
-      const block = message.blocks[blockIndex];
-      if (block.kind === 'image') return { missingTarget: `text-block:${patch.blockId}` };
-      const blocks = [...message.blocks];
-      blocks[blockIndex] = { ...block, text: `${block.text}${patch.delta}` };
-      const nodes = [...snapshot.nodes];
-      nodes[messageIndex] = { ...message, blocks };
-      return { snapshot: { ...snapshot, nodes } };
-    }
-    case 'tool.upsert':
-      return { snapshot: { ...snapshot, nodes: upsertTool(snapshot.nodes, patch.node) } };
-    case 'compaction.upsert':
-    case 'boundary.upsert':
-    case 'subagent.upsert':
-      return { snapshot: { ...snapshot, nodes: upsertById(snapshot.nodes, patch.node) } };
-    case 'queue.replace':
-      return { snapshot: { ...snapshot, queue: clone(patch.queue) } };
-    case 'interaction.upsert': {
-      const index = snapshot.pendingInteractions.findIndex((item) => item.id === patch.interaction.id);
-      const pendingInteractions = [...snapshot.pendingInteractions];
-      if (index < 0) pendingInteractions.push(clone(patch.interaction));
-      else pendingInteractions[index] = clone(patch.interaction);
-      return { snapshot: { ...snapshot, pendingInteractions } };
-    }
-    case 'interaction.remove':
-      return {
-        snapshot: {
-          ...snapshot,
-          pendingInteractions: snapshot.pendingInteractions.filter(
-            (item) => item.id !== patch.interactionId,
-          ),
-        },
-      };
-    case 'context.replace':
-      return { snapshot: { ...snapshot, context: clone(patch.context) } };
-    case 'snapshot.invalidated':
-      return { missingTarget: patch.reason };
-    default:
-      return { missingTarget: 'unknown patch' };
-  }
-}
-
-export function reduceConversationPatch(
-  state: ConversationReducerState,
-  value: unknown,
-): ConversationReducerState {
-  if (state.invalidation) return state;
-  if (!state.snapshot) {
-    return invalidate(state, {
-      code: 'snapshot-required',
-      reason: 'A Conversation snapshot is required before live patches',
-    });
-  }
-
-  const envelope = parseEnvelopeShell(value);
-  if (!envelope) {
-    return invalidate(state, {
-      code: 'malformed-envelope',
-      reason: 'Conversation patch envelope is malformed',
-    });
-  }
-  if (envelope.conversationId !== state.snapshot.conversation.id) return state;
-
-  const currentGeneration = state.snapshot.cursor.workerGeneration;
-  if (envelope.workerGeneration < currentGeneration) return state;
-  if (envelope.workerGeneration > currentGeneration) {
-    return invalidate(state, {
-      code: 'generation-gap',
-      reason: 'A newer worker generation requires a fresh snapshot',
-      expectedGeneration: currentGeneration,
-      actualGeneration: envelope.workerGeneration,
-    });
-  }
-
-  const currentSeq = state.snapshot.cursor.seq;
-  if (envelope.seq <= currentSeq) return state;
-  if (envelope.seq !== currentSeq + 1) {
-    return invalidate(state, {
-      code: 'sequence-gap',
-      reason: 'Conversation patch sequence has a gap',
-      expectedSeq: currentSeq + 1,
-      actualSeq: envelope.seq,
-    });
-  }
-
-  const patchRecord = asRecord(envelope.patch);
-  if (!patchRecord || !PATCH_OPS.has(String(patchRecord.op))) {
-    return invalidate(state, {
-      code: 'unknown-patch',
-      reason: 'Conversation patch operation is not supported',
-    });
-  }
-  if (!isPatch(envelope.patch)) {
-    return invalidate(state, {
-      code: 'unknown-patch',
-      reason: 'Conversation patch payload does not match its operation',
-    });
-  }
-  if (envelope.patch.op === 'snapshot.invalidated') {
-    return invalidate(state, {
-      code: 'explicit-invalidation',
-      reason: envelope.patch.reason,
-    });
-  }
-
-  const applied = applyPatch(state.snapshot, envelope.patch);
-  if ('missingTarget' in applied) {
-    return invalidate(state, {
-      code: 'patch-target-missing',
-      reason: `Conversation patch target is missing: ${applied.missingTarget}`,
-    });
-  }
-  return {
-    snapshot: {
-      ...applied.snapshot,
-      cursor: {
-        ...applied.snapshot.cursor,
-        workerGeneration: envelope.workerGeneration,
-        seq: envelope.seq,
-      },
-    },
-    invalidation: null,
-  };
-}
+export * from '../../shared/coding-conversation-reducer';
diff --git a/electron/coding-runtime/product-tool-protocol.ts b/electron/coding-runtime/product-tool-protocol.ts
index 164e39c..22a9382 100644
--- a/electron/coding-runtime/product-tool-protocol.ts
+++ b/electron/coding-runtime/product-tool-protocol.ts
@@ -1,156 +1 @@
-import type {
-  AgentBrowserDetailsV1,
-  ChangedFileDetailsV1,
-  GameAssetsDetailsV1,
-  KnownToolDetails,
-  RuntimeContextDetailsV1,
-  TaskStateDetailsV1,
-} from './contracts';
-
-const PRODUCT_TOOL_NAMES = new Set([
-  'agent_browser',
-  'game_asset_browser',
-  'game_asset_review',
-  'task_state',
-  'changed_file',
-  'runtime_context',
-]);
-
-function record(value: unknown): Record<string, unknown> | null {
-  return value !== null && typeof value === 'object' && !Array.isArray(value)
-    ? value as Record<string, unknown>
-    : null;
-}
-
-function text(value: unknown, max = 4096): string | null {
-  return typeof value === 'string' && value.trim() && value.length <= max ? value : null;
-}
-
-function strings(value: unknown, maxItems = 200): string[] | null {
-  if (!Array.isArray(value) || value.length > maxItems) return null;
-  const result: string[] = [];
-  for (const item of value) {
-    const normalized = text(item);
-    if (!normalized) return null;
-    result.push(normalized);
-  }
-  return result;
-}
-
-function relativePaths(value: unknown): string[] | null {
-  const paths = strings(value);
-  if (!paths) return null;
-  const result: string[] = [];
-  for (const candidate of paths) {
-    const normalized = candidate.replaceAll('\\', '/').replace(/^\.\//, '');
-    if (!normalized || normalized.startsWith('/') || /^[A-Za-z]:\//.test(normalized)
-      || normalized.split('/').some((segment) => segment === '..')) return null;
-    result.push(normalized);
-  }
-  return result;
-}
-
-function browserDetails(value: Record<string, unknown>): AgentBrowserDetailsV1 | null {
-  const actions = new Set([
-    'open', 'status', 'close', 'reset_profile', 'navigate', 'send_cdp', 'read_events', 'read_payload',
-  ]);
-  if (!actions.has(String(value.action))) return null;
-  const attachmentId = value.attachmentId === undefined ? undefined : text(value.attachmentId, 128);
-  const mime = value.mime === undefined ? undefined : text(value.mime, 128);
-  if ((value.attachmentId !== undefined && !attachmentId) || (value.mime !== undefined && !mime)) return null;
-  if (Boolean(attachmentId) !== Boolean(mime) || (attachmentId && value.action !== 'send_cdp')) return null;
-  return {
-    schema: 'agent-browser.v1',
-    action: value.action as AgentBrowserDetailsV1['action'],
-    ...(attachmentId ? { attachmentId } : {}),
-    ...(mime ? { mime } : {}),
-  };
-}
-
-function gameAssetDetails(value: Record<string, unknown>): GameAssetsDetailsV1 | null {
-  const invocationId = text(value.invocationId, 200);
-  const candidateIds = strings(value.candidateIds);
-  const pendingAssetIds = strings(value.pendingAssetIds);
-  const approvedAssetIds = strings(value.approvedAssetIds);
-  const discardedAssetIds = strings(value.discardedAssetIds);
-  if (!invocationId || !candidateIds || !pendingAssetIds || !approvedAssetIds || !discardedAssetIds) return null;
-  if (value.status !== 'pending' && value.status !== 'resolved') return null;
-  return {
-    schema: 'game-assets.v1',
-    invocationId,
-    candidateIds,
-    status: value.status,
-    pendingAssetIds,
-    approvedAssetIds,
-    discardedAssetIds,
-  };
-}
-
-function taskDetails(value: Record<string, unknown>): TaskStateDetailsV1 | null {
-  if (!Array.isArray(value.tasks) || value.tasks.length === 0 || value.tasks.length > 100) return null;
-  const tasks: TaskStateDetailsV1['tasks'] = [];
-  for (const candidate of value.tasks) {
-    const item = record(candidate);
-    const id = text(item?.id, 128);
-    const title = text(item?.title, 500);
-    if (!item || !id || !title || !['pending', 'running', 'complete', 'error'].includes(String(item.status))) {
-      return null;
-    }
-    tasks.push({ id, title, status: item.status as TaskStateDetailsV1['tasks'][number]['status'] });
-  }
-  return { schema: 'task-state.v1', tasks };
-}
-
-function runtimeContextDetails(value: Record<string, unknown>): RuntimeContextDetailsV1 | null {
-  if (!Array.isArray(value.skills) || value.skills.length > 100
-    || !Array.isArray(value.commands) || value.commands.length > 200) return null;
-  const skills: RuntimeContextDetailsV1['skills'] = [];
-  const commands: RuntimeContextDetailsV1['commands'] = [];
-  for (const candidate of value.skills) {
-    const item = record(candidate);
-    const id = text(item?.id, 128);
-    const name = text(item?.name, 200);
-    if (!item || !id || !name || typeof item.description !== 'string' || item.description.length > 2000
-      || typeof item.selected !== 'boolean') return null;
-    skills.push({ id, name, description: item.description, selected: item.selected });
-  }
-  for (const candidate of value.commands) {
-    const item = record(candidate);
-    const name = text(item?.name, 128);
-    const title = text(item?.title, 200);
-    if (!item || !name || !title || typeof item.description !== 'string' || item.description.length > 2000
-      || !['makelore', 'pi', 'skill'].includes(String(item.source))) return null;
-    const skillId = item.skillId === undefined ? undefined : text(item.skillId, 128);
-    if (item.skillId !== undefined && !skillId) return null;
-    commands.push({
-      name,
-      title,
-      description: item.description,
-      source: item.source as RuntimeContextDetailsV1['commands'][number]['source'],
-      ...(skillId ? { skillId } : {}),
-    });
-  }
-  return { schema: 'runtime-context.v1', skills, commands };
-}
-
-export function productToolDetails(value: unknown): Exclude<KnownToolDetails, { schema: 'subagent.v1' | 'write-lease.v1' }> | null {
-  const details = record(value);
-  if (!details) return null;
-  if (details.schema === 'changed-file.v1') {
-    const paths = relativePaths(details.paths);
-    return paths ? { schema: 'changed-file.v1', paths } satisfies ChangedFileDetailsV1 : null;
-  }
-  if (details.schema === 'task-state.v1') return taskDetails(details);
-  if (details.schema === 'agent-browser.v1') return browserDetails(details);
-  if (details.schema === 'game-assets.v1') return gameAssetDetails(details);
-  if (details.schema === 'runtime-context.v1') return runtimeContextDetails(details);
-  return null;
-}
-
-export function productToolDetailsOfResult(value: unknown) {
-  return productToolDetails(record(value)?.details);
-}
-
-export function isProductToolName(value: string): boolean {
-  return PRODUCT_TOOL_NAMES.has(value);
-}
+export * from '../../shared/coding-conversation-product-tool-protocol';
diff --git a/electron/coding-runtime/subagent-protocol.ts b/electron/coding-runtime/subagent-protocol.ts
index de1af59..95fe169 100644
--- a/electron/coding-runtime/subagent-protocol.ts
+++ b/electron/coding-runtime/subagent-protocol.ts
@@ -1,82 +1 @@
-import type { PublicUsage, SubagentDetailsV1 } from './contracts';
-
-const STATUSES = new Set(['queued', 'running', 'complete', 'error', 'aborted', 'skipped']);
-
-function recordValue(value: unknown): Record<string, unknown> | null {
-  return value !== null && typeof value === 'object' && !Array.isArray(value)
-    ? value as Record<string, unknown>
-    : null;
-}
-
-function publicUsage(value: unknown): PublicUsage | undefined {
-  const usage = recordValue(value);
-  if (!usage
-    || typeof usage.inputTokens !== 'number'
-    || typeof usage.outputTokens !== 'number'
-    || !Number.isFinite(usage.inputTokens)
-    || !Number.isFinite(usage.outputTokens)
-    || usage.inputTokens < 0
-    || usage.outputTokens < 0
-    || (usage.cacheReadTokens !== undefined
-      && (typeof usage.cacheReadTokens !== 'number'
-        || !Number.isFinite(usage.cacheReadTokens)
-        || usage.cacheReadTokens < 0))
-    || (usage.cacheWriteTokens !== undefined
-      && (typeof usage.cacheWriteTokens !== 'number'
-        || !Number.isFinite(usage.cacheWriteTokens)
-        || usage.cacheWriteTokens < 0))) {
-    return undefined;
-  }
-  return {
-    inputTokens: usage.inputTokens,
-    outputTokens: usage.outputTokens,
-    ...(typeof usage.cacheReadTokens === 'number' ? { cacheReadTokens: usage.cacheReadTokens } : {}),
-    ...(typeof usage.cacheWriteTokens === 'number' ? { cacheWriteTokens: usage.cacheWriteTokens } : {}),
-  };
-}
-
-export function projectSubagentDetailsV1(value: unknown): SubagentDetailsV1 | undefined {
-  const record = recordValue(value);
-  if (!record
-    || record.schema !== 'subagent.v1'
-    || typeof record.dispatchId !== 'string'
-    || !record.dispatchId.trim()
-    || !['single', 'parallel', 'chain'].includes(String(record.mode))
-    || !Array.isArray(record.tasks)
-    || record.tasks.length === 0
-    || record.tasks.length > 8) return undefined;
-  const tasks: SubagentDetailsV1['tasks'] = [];
-  for (const value of record.tasks) {
-    const task = recordValue(value);
-    if (!task
-      || typeof task.taskId !== 'string'
-      || !task.taskId.trim()
-      || typeof task.agentId !== 'string'
-      || !task.agentId.trim()
-      || (task.toolProfile !== 'read-only' && task.toolProfile !== 'coding')
-      || !STATUSES.has(String(task.status))
-      || (task.summary !== undefined && typeof task.summary !== 'string')
-      || (task.errorCode !== undefined && typeof task.errorCode !== 'string')) return undefined;
-    const usage = task.usage === undefined ? undefined : publicUsage(task.usage);
-    if (task.usage !== undefined && !usage) return undefined;
-    tasks.push({
-      taskId: task.taskId,
-      agentId: task.agentId,
-      toolProfile: task.toolProfile,
-      status: task.status as SubagentDetailsV1['tasks'][number]['status'],
-      ...(typeof task.summary === 'string' ? { summary: task.summary.slice(0, 4_000) } : {}),
-      ...(typeof task.errorCode === 'string' ? { errorCode: task.errorCode.slice(0, 64) } : {}),
-      ...(usage ? { usage } : {}),
-    });
-  }
-  return {
-    schema: 'subagent.v1',
-    dispatchId: record.dispatchId,
-    mode: record.mode as SubagentDetailsV1['mode'],
-    tasks,
-  };
-}
-
-export function subagentDetailsOfResult(value: unknown): SubagentDetailsV1 | undefined {
-  return projectSubagentDetailsV1(recordValue(value)?.details);
-}
+export * from '../../shared/coding-conversation-subagent-protocol';
diff --git a/shared/coding-conversation-contracts.ts b/shared/coding-conversation-contracts.ts
new file mode 100644
index 0000000..49cb690
--- /dev/null
+++ b/shared/coding-conversation-contracts.ts
@@ -0,0 +1,435 @@
+export type ConversationThinkingLevel = 'off' | 'minimal' | 'low' | 'medium' | 'high';
+
+export interface ProductModelRef {
+  accountId: string;
+  modelId: string;
+  thinkingLevel: ConversationThinkingLevel;
+}
+
+export interface ConversationModelState {
+  model: ProductModelRef | null;
+  modelResolution: 'resolved' | 'required';
+}
+
+export interface PublicUsage {
+  inputTokens: number;
+  outputTokens: number;
+  cacheReadTokens?: number;
+  cacheWriteTokens?: number;
+}
+
+export type CodingRuntimeErrorCode =
+  | 'CODING_RUNTIME_START_FAILED'
+  | 'CODING_RUNTIME_READY_TIMEOUT'
+  | 'CODING_RUNTIME_PROTOCOL_ERROR'
+  | 'CODING_PROVIDER_AUTH_REQUIRED'
+  | 'CODING_MODEL_UNAVAILABLE'
+  | 'CODING_SESSION_UNREADABLE'
+  | 'CODING_STORAGE_WRITE_FAILED'
+  | 'CODING_REQUEST_UNCERTAIN'
+  | 'CODING_MIGRATION_MODEL_REQUIRED'
+  | 'CODING_CONVERSATION_NOT_FOUND';
+
+export interface CodingRuntimePublicError {
+  code: CodingRuntimeErrorCode;
+  message: string;
+  recoverable: boolean;
+}
+
+export type ConversationRunStatus =
+  | 'idle'
+  | 'preparing'
+  | 'queued'
+  | 'running'
+  | 'retrying'
+  | 'compacting'
+  | 'aborting'
+  | 'error';
+
+export type PromptMode = 'prompt' | 'steer' | 'follow-up';
+
+export interface ConversationRunState {
+  status: ConversationRunStatus;
+  runId?: string;
+  mode?: PromptMode;
+  startedAt?: number;
+  settledAt?: number;
+  terminalReason?: 'completed' | 'aborted' | 'failed';
+  retry?: {
+    attempt: number;
+    delayMs: number;
+  };
+  error?: CodingRuntimePublicError;
+}
+
+export interface ConversationQueueItem {
+  id: string;
+  clientRequestId: string;
+  mode: 'steer' | 'follow-up';
+  text: string;
+  attachmentIds: string[];
+}
+
+export interface ConversationQueueState {
+  items: ConversationQueueItem[];
+}
+
+export interface ConversationContextState {
+  usedTokens: number;
+  contextWindow: number;
+  outputLimit?: number;
+  compaction: 'idle' | 'running';
+  lastCompactionId?: string;
+  recalculating?: boolean;
+}
+
+export interface ConversationInteractionOption {
+  id: string;
+  label: string;
+  description?: string;
+}
+
+export interface ConversationInteraction {
+  id: string;
+  conversationId: string;
+  runId: string;
+  kind: 'select' | 'confirm' | 'input' | 'editor';
+  title: string;
+  message?: string;
+  options?: ConversationInteractionOption[];
+  status: 'pending' | 'answered' | 'rejected' | 'cancelled';
+}
+
+export interface PublicWorkerState {
+  status: 'stopped' | 'starting' | 'ready' | 'recovering' | 'error';
+  generation: number;
+  error?: CodingRuntimePublicError;
+}
+
+export type ConversationContentBlock =
+  | {
+    kind: 'text';
+    id: string;
+    text: string;
+    status: 'streaming' | 'complete';
+  }
+  | {
+    kind: 'thinking';
+    id: string;
+    text: string;
+    status: 'streaming' | 'complete';
+  }
+  | {
+    kind: 'image';
+    id: string;
+    attachmentId: string;
+    mime: string;
+  };
+
+export interface ConversationMessageNode {
+  kind: 'message';
+  id: string;
+  sourceEntryId?: string;
+  clientRequestId?: string;
+  role: 'user' | 'assistant';
+  status: 'optimistic' | 'streaming' | 'complete' | 'error' | 'aborted';
+  blocks: ConversationContentBlock[];
+  usage?: PublicUsage;
+  stopReason?: 'stop' | 'length' | 'tool-use' | 'error' | 'aborted';
+}
+
+export interface ChangedFileDetailsV1 {
+  schema: 'changed-file.v1';
+  paths: string[];
+}
+
+export interface TaskStateDetailsV1 {
+  schema: 'task-state.v1';
+  tasks: Array<{
+    id: string;
+    title: string;
+    status: 'pending' | 'running' | 'complete' | 'error';
+  }>;
+}
+
+export interface WriteLeaseDetailsV1 {
+  schema: 'write-lease.v1';
+  status: 'waiting' | 'held' | 'released';
+}
+
+export interface AgentBrowserDetailsV1 {
+  schema: 'agent-browser.v1';
+  action: 'open' | 'status' | 'close' | 'reset_profile' | 'navigate' | 'send_cdp' | 'read_events' | 'read_payload';
+  attachmentId?: string;
+  mime?: string;
+}
+
+export interface GameAssetsDetailsV1 {
+  schema: 'game-assets.v1';
+  invocationId: string;
+  candidateIds: string[];
+  status: 'pending' | 'resolved';
+  pendingAssetIds: string[];
+  approvedAssetIds: string[];
+  discardedAssetIds: string[];
+}
+
+export interface RuntimeContextDetailsV1 {
+  schema: 'runtime-context.v1';
+  skills: Array<{
+    id: string;
+    name: string;
+    description: string;
+    selected: boolean;
+  }>;
+  commands: Array<{
+    name: string;
+    title: string;
+    description: string;
+    source: 'makelore' | 'pi' | 'skill';
+    skillId?: string;
+  }>;
+}
+
+export interface SubagentDetailsV1 {
+  schema: 'subagent.v1';
+  dispatchId: string;
+  mode: 'single' | 'parallel' | 'chain';
+  tasks: Array<{
+    taskId: string;
+    agentId: string;
+    toolProfile: 'read-only' | 'coding';
+    status: 'queued' | 'running' | 'complete' | 'error' | 'aborted' | 'skipped';
+    summary?: string;
+    errorCode?: string;
+    usage?: PublicUsage;
+  }>;
+}
+
+export type KnownToolDetails =
+  | ChangedFileDetailsV1
+  | TaskStateDetailsV1
+  | WriteLeaseDetailsV1
+  | AgentBrowserDetailsV1
+  | GameAssetsDetailsV1
+  | RuntimeContextDetailsV1
+  | SubagentDetailsV1;
+
+export interface ConversationToolNode {
+  kind: 'tool';
+  id: string;
+  toolCallId: string;
+  toolName: string;
+  title: string;
+  inputText: string;
+  status: 'declared' | 'waiting' | 'running' | 'complete' | 'error' | 'aborted';
+  output: ConversationContentBlock[];
+  details?: KnownToolDetails;
+}
+
+export interface ConversationCompactionNode {
+  kind: 'compaction';
+  id: string;
+  runId: string;
+  source: 'manual' | 'automatic';
+  status: 'running' | 'complete' | 'error';
+  willRetry: boolean;
+  summary?: string;
+}
+
+export interface ConversationBoundaryNode {
+  kind: 'boundary';
+  id: string;
+  runId: string;
+  boundary: 'turn-start' | 'turn-end' | 'retry';
+  attempt?: number;
+  delayMs?: number;
+}
+
+export interface ConversationSubagentNode {
+  kind: 'subagent';
+  id: string;
+  runId: string;
+  details: SubagentDetailsV1;
+}
+
+export interface ConversationNoticeNode {
+  kind: 'notice';
+  id: string;
+  code: string;
+  level: 'info' | 'warning' | 'error';
+  message: string;
+}
+
+export type ConversationNode =
+  | ConversationMessageNode
+  | ConversationToolNode
+  | ConversationCompactionNode
+  | ConversationBoundaryNode
+  | ConversationSubagentNode
+  | ConversationNoticeNode;
+
+export interface ConversationSnapshot {
+  schemaVersion: 1;
+  conversation: {
+    id: string;
+    projectId: string;
+    agentId: string;
+    title: string;
+    model: ConversationModelState;
+  };
+  nodes: ConversationNode[];
+  run: ConversationRunState;
+  queue: ConversationQueueState;
+  context: ConversationContextState;
+  pendingInteractions: ConversationInteraction[];
+  worker: PublicWorkerState;
+  cursor: {
+    workerGeneration: number;
+    seq: number;
+    leafEntryId?: string;
+  };
+}
+
+export type ConversationPatch =
+  | { op: 'worker.state'; state: PublicWorkerState }
+  | { op: 'run.state'; run: ConversationRunState }
+  | { op: 'message.upsert'; node: ConversationMessageNode }
+  | { op: 'message.block-delta'; messageId: string; blockId: string; delta: string }
+  | { op: 'tool.upsert'; node: ConversationToolNode }
+  | { op: 'compaction.upsert'; node: ConversationCompactionNode }
+  | { op: 'boundary.upsert'; node: ConversationBoundaryNode }
+  | { op: 'subagent.upsert'; node: ConversationSubagentNode }
+  | { op: 'queue.replace'; queue: ConversationQueueState }
+  | { op: 'interaction.upsert'; interaction: ConversationInteraction }
+  | { op: 'interaction.remove'; interactionId: string }
+  | { op: 'context.replace'; context: ConversationContextState }
+  | { op: 'snapshot.invalidated'; reason: string };
+
+export interface ConversationPatchEnvelope {
+  conversationId: string;
+  workerGeneration: number;
+  runId?: string;
+  seq: number;
+  at: number;
+  patch: ConversationPatch;
+}
+
+export interface PrepareConversationInput {
+  conversationId: string;
+  projectId: string;
+  agentId: string;
+  title: string;
+  model: ConversationModelState;
+}
+
+export interface ConversationRuntimeState {
+  conversationId: string;
+  status: PublicWorkerState['status'];
+  workerGeneration: number;
+  error?: CodingRuntimePublicError;
+}
+
+export interface PromptConversationInput {
+  clientRequestId: string;
+  conversationId: string;
+  mode: PromptMode;
+  text: string;
+  attachments: Array<{ attachmentId: string }>;
+}
+
+export interface QueueMessageInput {
+  clientRequestId: string;
+  conversationId: string;
+  text: string;
+  attachments: Array<{ attachmentId: string }>;
+}
+
+export interface PromptAcceptance {
+  accepted: true;
+  conversationId: string;
+  clientRequestId: string;
+  runId: string;
+  mode: PromptMode;
+  queuePosition?: number;
+}
+
+export interface QueueAcceptance {
+  accepted: true;
+  conversationId: string;
+  clientRequestId: string;
+  mode: 'steer' | 'follow-up';
+  queuePosition: number;
+}
+
+export interface SetConversationModelInput {
+  conversationId: string;
+  accountId: string;
+  modelId: string;
+}
+
+export interface SetThinkingLevelInput {
+  conversationId: string;
+  thinkingLevel: ConversationThinkingLevel;
+}
+
+export interface ForkConversationInput {
+  sourceConversationId: string;
+  sourceEntryId?: string;
+  conversation: PrepareConversationInput;
+}
+
+export interface ForkResult {
+  conversationId: string;
+  snapshot: ConversationSnapshot;
+}
+
+export interface CodingRuntimeCommand {
+  name: string;
+  description?: string;
+}
+
+export type ConversationInteractionResponse =
+  | { interactionId: string; cancelled: true }
+  | { interactionId: string; optionId: string }
+  | { interactionId: string; confirmed: boolean }
+  | { interactionId: string; value: string };
+
+export interface CodingRuntimeDiagnostics {
+  revision: {
+    provider: number;
+    resources: number;
+  };
+  workers: Array<{
+    conversationId: string;
+    generation: number;
+    state: 'spawning' | 'ready' | 'queued' | 'running' | 'idle' | 'crashed';
+    stage: 'starting' | 'idle' | 'queued' | 'running' | 'failed';
+  }>;
+}
+
+export interface CodingConversationRuntime {
+  prepare(input: PrepareConversationInput): Promise<ConversationRuntimeState>;
+  getSnapshot(conversationId: string): Promise<ConversationSnapshot>;
+  prompt(input: PromptConversationInput): Promise<PromptAcceptance>;
+  steer(input: QueueMessageInput): Promise<QueueAcceptance>;
+  followUp(input: QueueMessageInput): Promise<QueueAcceptance>;
+  abort(conversationId: string): Promise<void>;
+  validateModel(model: ProductModelRef): Promise<ProductModelRef>;
+  setModel(input: SetConversationModelInput): Promise<ConversationModelState>;
+  setThinking(input: SetThinkingLevelInput): Promise<ConversationModelState>;
+  compact(conversationId: string): Promise<void>;
+  fork(input: ForkConversationInput): Promise<ForkResult>;
+  recover(conversationId: string): Promise<ConversationRuntimeState>;
+  dispose(conversationId: string): Promise<void>;
+  listCommands(conversationId: string): Promise<CodingRuntimeCommand[]>;
+  listInteractions(conversationId?: string): Promise<ConversationInteraction[]>;
+  respondInteraction(
+    conversationId: string,
+    response: ConversationInteractionResponse,
+  ): Promise<void>;
+  getDiagnostics(): CodingRuntimeDiagnostics;
+  markProviderStale(): void;
+  markResourcesStale(): void;
+  subscribe(listener: (patch: ConversationPatchEnvelope) => void): () => void;
+}
diff --git a/shared/coding-conversation-product-tool-protocol.ts b/shared/coding-conversation-product-tool-protocol.ts
new file mode 100644
index 0000000..396f5ab
--- /dev/null
+++ b/shared/coding-conversation-product-tool-protocol.ts
@@ -0,0 +1,156 @@
+import type {
+  AgentBrowserDetailsV1,
+  ChangedFileDetailsV1,
+  GameAssetsDetailsV1,
+  KnownToolDetails,
+  RuntimeContextDetailsV1,
+  TaskStateDetailsV1,
+} from './coding-conversation-contracts';
+
+const PRODUCT_TOOL_NAMES = new Set([
+  'agent_browser',
+  'game_asset_browser',
+  'game_asset_review',
+  'task_state',
+  'changed_file',
+  'runtime_context',
+]);
+
+function record(value: unknown): Record<string, unknown> | null {
+  return value !== null && typeof value === 'object' && !Array.isArray(value)
+    ? value as Record<string, unknown>
+    : null;
+}
+
+function text(value: unknown, max = 4096): string | null {
+  return typeof value === 'string' && value.trim() && value.length <= max ? value : null;
+}
+
+function strings(value: unknown, maxItems = 200): string[] | null {
+  if (!Array.isArray(value) || value.length > maxItems) return null;
+  const result: string[] = [];
+  for (const item of value) {
+    const normalized = text(item);
+    if (!normalized) return null;
+    result.push(normalized);
+  }
+  return result;
+}
+
+function relativePaths(value: unknown): string[] | null {
+  const paths = strings(value);
+  if (!paths) return null;
+  const result: string[] = [];
+  for (const candidate of paths) {
+    const normalized = candidate.replaceAll('\\', '/').replace(/^\.\//, '');
+    if (!normalized || normalized.startsWith('/') || /^[A-Za-z]:\//.test(normalized)
+      || normalized.split('/').some((segment) => segment === '..')) return null;
+    result.push(normalized);
+  }
+  return result;
+}
+
+function browserDetails(value: Record<string, unknown>): AgentBrowserDetailsV1 | null {
+  const actions = new Set([
+    'open', 'status', 'close', 'reset_profile', 'navigate', 'send_cdp', 'read_events', 'read_payload',
+  ]);
+  if (!actions.has(String(value.action))) return null;
+  const attachmentId = value.attachmentId === undefined ? undefined : text(value.attachmentId, 128);
+  const mime = value.mime === undefined ? undefined : text(value.mime, 128);
+  if ((value.attachmentId !== undefined && !attachmentId) || (value.mime !== undefined && !mime)) return null;
+  if (Boolean(attachmentId) !== Boolean(mime) || (attachmentId && value.action !== 'send_cdp')) return null;
+  return {
+    schema: 'agent-browser.v1',
+    action: value.action as AgentBrowserDetailsV1['action'],
+    ...(attachmentId ? { attachmentId } : {}),
+    ...(mime ? { mime } : {}),
+  };
+}
+
+function gameAssetDetails(value: Record<string, unknown>): GameAssetsDetailsV1 | null {
+  const invocationId = text(value.invocationId, 200);
+  const candidateIds = strings(value.candidateIds);
+  const pendingAssetIds = strings(value.pendingAssetIds);
+  const approvedAssetIds = strings(value.approvedAssetIds);
+  const discardedAssetIds = strings(value.discardedAssetIds);
+  if (!invocationId || !candidateIds || !pendingAssetIds || !approvedAssetIds || !discardedAssetIds) return null;
+  if (value.status !== 'pending' && value.status !== 'resolved') return null;
+  return {
+    schema: 'game-assets.v1',
+    invocationId,
+    candidateIds,
+    status: value.status,
+    pendingAssetIds,
+    approvedAssetIds,
+    discardedAssetIds,
+  };
+}
+
+function taskDetails(value: Record<string, unknown>): TaskStateDetailsV1 | null {
+  if (!Array.isArray(value.tasks) || value.tasks.length === 0 || value.tasks.length > 100) return null;
+  const tasks: TaskStateDetailsV1['tasks'] = [];
+  for (const candidate of value.tasks) {
+    const item = record(candidate);
+    const id = text(item?.id, 128);
+    const title = text(item?.title, 500);
+    if (!item || !id || !title || !['pending', 'running', 'complete', 'error'].includes(String(item.status))) {
+      return null;
+    }
+    tasks.push({ id, title, status: item.status as TaskStateDetailsV1['tasks'][number]['status'] });
+  }
+  return { schema: 'task-state.v1', tasks };
+}
+
+function runtimeContextDetails(value: Record<string, unknown>): RuntimeContextDetailsV1 | null {
+  if (!Array.isArray(value.skills) || value.skills.length > 100
+    || !Array.isArray(value.commands) || value.commands.length > 200) return null;
+  const skills: RuntimeContextDetailsV1['skills'] = [];
+  const commands: RuntimeContextDetailsV1['commands'] = [];
+  for (const candidate of value.skills) {
+    const item = record(candidate);
+    const id = text(item?.id, 128);
+    const name = text(item?.name, 200);
+    if (!item || !id || !name || typeof item.description !== 'string' || item.description.length > 2000
+      || typeof item.selected !== 'boolean') return null;
+    skills.push({ id, name, description: item.description, selected: item.selected });
+  }
+  for (const candidate of value.commands) {
+    const item = record(candidate);
+    const name = text(item?.name, 128);
+    const title = text(item?.title, 200);
+    if (!item || !name || !title || typeof item.description !== 'string' || item.description.length > 2000
+      || !['makelore', 'pi', 'skill'].includes(String(item.source))) return null;
+    const skillId = item.skillId === undefined ? undefined : text(item.skillId, 128);
+    if (item.skillId !== undefined && !skillId) return null;
+    commands.push({
+      name,
+      title,
+      description: item.description,
+      source: item.source as RuntimeContextDetailsV1['commands'][number]['source'],
+      ...(skillId ? { skillId } : {}),
+    });
+  }
+  return { schema: 'runtime-context.v1', skills, commands };
+}
+
+export function productToolDetails(value: unknown): Exclude<KnownToolDetails, { schema: 'subagent.v1' | 'write-lease.v1' }> | null {
+  const details = record(value);
+  if (!details) return null;
+  if (details.schema === 'changed-file.v1') {
+    const paths = relativePaths(details.paths);
+    return paths ? { schema: 'changed-file.v1', paths } satisfies ChangedFileDetailsV1 : null;
+  }
+  if (details.schema === 'task-state.v1') return taskDetails(details);
+  if (details.schema === 'agent-browser.v1') return browserDetails(details);
+  if (details.schema === 'game-assets.v1') return gameAssetDetails(details);
+  if (details.schema === 'runtime-context.v1') return runtimeContextDetails(details);
+  return null;
+}
+
+export function productToolDetailsOfResult(value: unknown) {
+  return productToolDetails(record(value)?.details);
+}
+
+export function isProductToolName(value: string): boolean {
+  return PRODUCT_TOOL_NAMES.has(value);
+}
diff --git a/shared/coding-conversation-reducer.ts b/shared/coding-conversation-reducer.ts
new file mode 100644
index 0000000..c56c345
--- /dev/null
+++ b/shared/coding-conversation-reducer.ts
@@ -0,0 +1,554 @@
+import type {
+  CodingRuntimePublicError,
+  ConversationContentBlock,
+  ConversationInteraction,
+  ConversationMessageNode,
+  ConversationNode,
+  ConversationPatch,
+  ConversationPatchEnvelope,
+  ConversationQueueState,
+  ConversationRunState,
+  ConversationSnapshot,
+  ConversationSubagentNode,
+  ConversationToolNode,
+  KnownToolDetails,
+  PublicWorkerState,
+} from './coding-conversation-contracts';
+import { productToolDetails } from './coding-conversation-product-tool-protocol';
+import { projectSubagentDetailsV1 } from './coding-conversation-subagent-protocol';
+
+export type ConversationInvalidationCode =
+  | 'snapshot-required'
+  | 'unsupported-schema'
+  | 'malformed-snapshot'
+  | 'malformed-envelope'
+  | 'unknown-patch'
+  | 'generation-gap'
+  | 'sequence-gap'
+  | 'patch-target-missing'
+  | 'explicit-invalidation';
+
+export interface ConversationInvalidation {
+  code: ConversationInvalidationCode;
+  reason: string;
+  expectedGeneration?: number;
+  actualGeneration?: number;
+  expectedSeq?: number;
+  actualSeq?: number;
+}
+
+export interface ConversationReducerState {
+  snapshot: ConversationSnapshot | null;
+  invalidation: ConversationInvalidation | null;
+}
+
+const RUN_STATUSES = new Set([
+  'idle',
+  'preparing',
+  'queued',
+  'running',
+  'retrying',
+  'compacting',
+  'aborting',
+  'error',
+]);
+
+const WORKER_STATUSES = new Set(['stopped', 'starting', 'ready', 'recovering', 'error']);
+const ERROR_CODES = new Set([
+  'CODING_RUNTIME_START_FAILED',
+  'CODING_RUNTIME_READY_TIMEOUT',
+  'CODING_RUNTIME_PROTOCOL_ERROR',
+  'CODING_PROVIDER_AUTH_REQUIRED',
+  'CODING_MODEL_UNAVAILABLE',
+  'CODING_SESSION_UNREADABLE',
+  'CODING_STORAGE_WRITE_FAILED',
+  'CODING_REQUEST_UNCERTAIN',
+  'CODING_MIGRATION_MODEL_REQUIRED',
+  'CODING_CONVERSATION_NOT_FOUND',
+]);
+const PATCH_OPS = new Set([
+  'worker.state',
+  'run.state',
+  'message.upsert',
+  'message.block-delta',
+  'tool.upsert',
+  'compaction.upsert',
+  'boundary.upsert',
+  'subagent.upsert',
+  'queue.replace',
+  'interaction.upsert',
+  'interaction.remove',
+  'context.replace',
+  'snapshot.invalidated',
+]);
+
+function clone<T>(value: T): T {
+  return structuredClone(value);
+}
+
+function asRecord(value: unknown): Record<string, unknown> | null {
+  return value !== null && typeof value === 'object' && !Array.isArray(value)
+    ? value as Record<string, unknown>
+    : null;
+}
+
+function isNonEmptyString(value: unknown): value is string {
+  return typeof value === 'string' && value.length > 0;
+}
+
+function isNonNegativeInteger(value: unknown): value is number {
+  return Number.isInteger(value) && Number(value) >= 0;
+}
+
+function isOptionalNumber(value: unknown): boolean {
+  return value === undefined || typeof value === 'number';
+}
+
+function isPublicError(value: unknown): value is CodingRuntimePublicError {
+  const record = asRecord(value);
+  return record !== null
+    && ERROR_CODES.has(String(record.code))
+    && isNonEmptyString(record.message)
+    && typeof record.recoverable === 'boolean';
+}
+
+function isModelState(value: unknown): boolean {
+  const record = asRecord(value);
+  if (!record || !['resolved', 'required'].includes(String(record.modelResolution))) return false;
+  if (record.model === null) return record.modelResolution === 'required';
+  const model = asRecord(record.model);
+  return model !== null
+    && isNonEmptyString(model.accountId)
+    && isNonEmptyString(model.modelId)
+    && ['off', 'minimal', 'low', 'medium', 'high'].includes(String(model.thinkingLevel))
+    && record.modelResolution === 'resolved';
+}
+
+function isUsage(value: unknown): boolean {
+  const record = asRecord(value);
+  return record !== null
+    && typeof record.inputTokens === 'number'
+    && typeof record.outputTokens === 'number'
+    && isOptionalNumber(record.cacheReadTokens)
+    && isOptionalNumber(record.cacheWriteTokens);
+}
+
+function isContentBlock(value: unknown): value is ConversationContentBlock {
+  const record = asRecord(value);
+  if (!record || !isNonEmptyString(record.id) || !isNonEmptyString(record.kind)) return false;
+  if (record.kind === 'image') {
+    return isNonEmptyString(record.attachmentId) && isNonEmptyString(record.mime);
+  }
+  return (record.kind === 'text' || record.kind === 'thinking')
+    && typeof record.text === 'string'
+    && (record.status === 'streaming' || record.status === 'complete');
+}
+
+function isKnownToolDetails(value: unknown): value is KnownToolDetails {
+  const record = asRecord(value);
+  if (!record || !isNonEmptyString(record.schema)) return false;
+  if (productToolDetails(record)) return true;
+  if (record.schema === 'write-lease.v1') {
+    return record.status === 'waiting' || record.status === 'held' || record.status === 'released';
+  }
+  if (record.schema === 'subagent.v1') {
+    return projectSubagentDetailsV1(record) !== undefined;
+  }
+  return false;
+}
+
+function isMessageNode(value: unknown): value is ConversationMessageNode {
+  const record = asRecord(value);
+  return record !== null
+    && record.kind === 'message'
+    && isNonEmptyString(record.id)
+    && (record.role === 'user' || record.role === 'assistant')
+    && ['optimistic', 'streaming', 'complete', 'error', 'aborted'].includes(String(record.status))
+    && Array.isArray(record.blocks)
+    && record.blocks.every(isContentBlock)
+    && (record.usage === undefined || isUsage(record.usage));
+}
+
+function isToolNode(value: unknown): value is ConversationToolNode {
+  const record = asRecord(value);
+  return record !== null
+    && record.kind === 'tool'
+    && isNonEmptyString(record.id)
+    && isNonEmptyString(record.toolCallId)
+    && isNonEmptyString(record.toolName)
+    && typeof record.title === 'string'
+    && typeof record.inputText === 'string'
+    && ['declared', 'waiting', 'running', 'complete', 'error', 'aborted']
+      .includes(String(record.status))
+    && Array.isArray(record.output)
+    && record.output.every(isContentBlock)
+    && (record.details === undefined || isKnownToolDetails(record.details));
+}
+
+function isSubagentNode(value: unknown): value is ConversationSubagentNode {
+  const record = asRecord(value);
+  return record !== null
+    && record.kind === 'subagent'
+    && isNonEmptyString(record.id)
+    && isNonEmptyString(record.runId)
+    && isKnownToolDetails(record.details)
+    && record.details.schema === 'subagent.v1';
+}
+
+function isConversationNode(value: unknown): value is ConversationNode {
+  const record = asRecord(value);
+  if (!record || !isNonEmptyString(record.kind) || !isNonEmptyString(record.id)) return false;
+  if (record.kind === 'message') return isMessageNode(record);
+  if (record.kind === 'tool') return isToolNode(record);
+  if (record.kind === 'subagent') return isSubagentNode(record);
+  if (record.kind === 'compaction') {
+    return isNonEmptyString(record.runId)
+      && ['manual', 'automatic'].includes(String(record.source))
+      && ['running', 'complete', 'error'].includes(String(record.status))
+      && typeof record.willRetry === 'boolean';
+  }
+  if (record.kind === 'boundary') {
+    return isNonEmptyString(record.runId)
+      && ['turn-start', 'turn-end', 'retry'].includes(String(record.boundary));
+  }
+  if (record.kind === 'notice') {
+    return isNonEmptyString(record.code)
+      && ['info', 'warning', 'error'].includes(String(record.level))
+      && typeof record.message === 'string';
+  }
+  return false;
+}
+
+function isInteraction(value: unknown): value is ConversationInteraction {
+  const record = asRecord(value);
+  return record !== null
+    && isNonEmptyString(record.id)
+    && isNonEmptyString(record.conversationId)
+    && isNonEmptyString(record.runId)
+    && ['select', 'confirm', 'input', 'editor'].includes(String(record.kind))
+    && typeof record.title === 'string'
+    && ['pending', 'answered', 'rejected', 'cancelled'].includes(String(record.status));
+}
+
+function isRunState(value: unknown): value is ConversationRunState {
+  const record = asRecord(value);
+  return record !== null
+    && RUN_STATUSES.has(String(record.status))
+    && (record.error === undefined || isPublicError(record.error));
+}
+
+function isQueueState(value: unknown): value is ConversationQueueState {
+  const record = asRecord(value);
+  return record !== null && Array.isArray(record.items) && record.items.every((item) => {
+    const queueItem = asRecord(item);
+    return queueItem !== null
+      && isNonEmptyString(queueItem.id)
+      && isNonEmptyString(queueItem.clientRequestId)
+      && ['steer', 'follow-up'].includes(String(queueItem.mode))
+      && typeof queueItem.text === 'string'
+      && Array.isArray(queueItem.attachmentIds)
+      && queueItem.attachmentIds.every(isNonEmptyString);
+  });
+}
+
+function isWorkerState(value: unknown): value is PublicWorkerState {
+  const record = asRecord(value);
+  return record !== null
+    && WORKER_STATUSES.has(String(record.status))
+    && isNonNegativeInteger(record.generation)
+    && (record.error === undefined || isPublicError(record.error));
+}
+
+export function isConversationSnapshot(value: unknown): value is ConversationSnapshot {
+  const record = asRecord(value);
+  const conversation = asRecord(record?.conversation);
+  const cursor = asRecord(record?.cursor);
+  const context = asRecord(record?.context);
+  const worker = record?.worker;
+  return record !== null
+    && record.schemaVersion === 1
+    && conversation !== null
+    && isNonEmptyString(conversation.id)
+    && isNonEmptyString(conversation.projectId)
+    && isNonEmptyString(conversation.agentId)
+    && typeof conversation.title === 'string'
+    && isModelState(conversation.model)
+    && Array.isArray(record.nodes)
+    && record.nodes.every(isConversationNode)
+    && isRunState(record.run)
+    && isQueueState(record.queue)
+    && context !== null
+    && typeof context.usedTokens === 'number'
+    && typeof context.contextWindow === 'number'
+    && ['idle', 'running'].includes(String(context.compaction))
+    && (context.recalculating === undefined || typeof context.recalculating === 'boolean')
+    && Array.isArray(record.pendingInteractions)
+    && record.pendingInteractions.every(isInteraction)
+    && isWorkerState(worker)
+    && cursor !== null
+    && isNonNegativeInteger(cursor.workerGeneration)
+    && isNonNegativeInteger(cursor.seq)
+    && asRecord(worker)?.generation === cursor.workerGeneration;
+}
+
+function isPatch(value: unknown): value is ConversationPatch {
+  const record = asRecord(value);
+  if (!record || !PATCH_OPS.has(String(record.op))) return false;
+  switch (record.op) {
+    case 'worker.state':
+      return isWorkerState(record.state);
+    case 'run.state':
+      return isRunState(record.run);
+    case 'message.upsert':
+      return isMessageNode(record.node);
+    case 'message.block-delta':
+      return isNonEmptyString(record.messageId)
+        && isNonEmptyString(record.blockId)
+        && typeof record.delta === 'string';
+    case 'tool.upsert':
+      return isToolNode(record.node);
+    case 'compaction.upsert':
+      return isConversationNode(record.node) && record.node.kind === 'compaction';
+    case 'boundary.upsert':
+      return isConversationNode(record.node) && record.node.kind === 'boundary';
+    case 'subagent.upsert':
+      return isSubagentNode(record.node);
+    case 'queue.replace':
+      return isQueueState(record.queue);
+    case 'interaction.upsert':
+      return isInteraction(record.interaction);
+    case 'interaction.remove':
+      return isNonEmptyString(record.interactionId);
+    case 'context.replace': {
+      const context = asRecord(record.context);
+      return context !== null
+        && typeof context.usedTokens === 'number'
+        && typeof context.contextWindow === 'number'
+        && ['idle', 'running'].includes(String(context.compaction))
+        && (context.recalculating === undefined || typeof context.recalculating === 'boolean');
+    }
+    case 'snapshot.invalidated':
+      return isNonEmptyString(record.reason);
+    default:
+      return false;
+  }
+}
+
+function parseEnvelopeShell(value: unknown): Omit<ConversationPatchEnvelope, 'patch'> & { patch: unknown } | null {
+  const record = asRecord(value);
+  if (!record
+    || !isNonEmptyString(record.conversationId)
+    || !isNonNegativeInteger(record.workerGeneration)
+    || !isNonNegativeInteger(record.seq)
+    || typeof record.at !== 'number') {
+    return null;
+  }
+  return record as unknown as Omit<ConversationPatchEnvelope, 'patch'> & { patch: unknown };
+}
+
+function invalidate(
+  state: ConversationReducerState,
+  invalidation: ConversationInvalidation,
+): ConversationReducerState {
+  return { snapshot: state.snapshot, invalidation };
+}
+
+export function createConversationReducerState(snapshot?: unknown): ConversationReducerState {
+  if (snapshot === undefined) return { snapshot: null, invalidation: null };
+  return replaceConversationSnapshot({ snapshot: null, invalidation: null }, snapshot);
+}
+
+export function replaceConversationSnapshot(
+  state: ConversationReducerState,
+  snapshot: unknown,
+): ConversationReducerState {
+  const record = asRecord(snapshot);
+  if (record?.schemaVersion !== 1) {
+    return invalidate(state, {
+      code: 'unsupported-schema',
+      reason: 'Conversation snapshot schemaVersion must equal 1',
+    });
+  }
+  if (!isConversationSnapshot(snapshot)) {
+    return invalidate(state, {
+      code: 'malformed-snapshot',
+      reason: 'Conversation snapshot does not match the product contract',
+    });
+  }
+  return { snapshot: clone(snapshot), invalidation: null };
+}
+
+function upsertMessage(nodes: ConversationNode[], incoming: ConversationMessageNode): ConversationNode[] {
+  const index = nodes.findIndex((node) => node.kind === 'message' && (
+    node.id === incoming.id
+    || (incoming.sourceEntryId !== undefined && node.sourceEntryId === incoming.sourceEntryId)
+    || (incoming.clientRequestId !== undefined && node.clientRequestId === incoming.clientRequestId)
+  ));
+  if (index < 0) return [...nodes, clone(incoming)];
+  const existing = nodes[index] as ConversationMessageNode;
+  const next = [...nodes];
+  next[index] = { ...clone(incoming), id: existing.id };
+  return next;
+}
+
+function upsertTool(nodes: ConversationNode[], incoming: ConversationToolNode): ConversationNode[] {
+  const index = nodes.findIndex((node) => node.kind === 'tool' && (
+    node.id === incoming.id || node.toolCallId === incoming.toolCallId
+  ));
+  if (index < 0) return [...nodes, clone(incoming)];
+  const existing = nodes[index] as ConversationToolNode;
+  const next = [...nodes];
+  next[index] = { ...clone(incoming), id: existing.id };
+  return next;
+}
+
+function upsertById(nodes: ConversationNode[], incoming: ConversationNode): ConversationNode[] {
+  const index = nodes.findIndex((node) => node.kind === incoming.kind && node.id === incoming.id);
+  if (index < 0) return [...nodes, clone(incoming)];
+  const next = [...nodes];
+  next[index] = clone(incoming);
+  return next;
+}
+
+function applyPatch(
+  snapshot: ConversationSnapshot,
+  patch: ConversationPatch,
+): { snapshot: ConversationSnapshot } | { missingTarget: string } {
+  switch (patch.op) {
+    case 'worker.state':
+      return { snapshot: { ...snapshot, worker: clone(patch.state) } };
+    case 'run.state':
+      return { snapshot: { ...snapshot, run: clone(patch.run) } };
+    case 'message.upsert':
+      return { snapshot: { ...snapshot, nodes: upsertMessage(snapshot.nodes, patch.node) } };
+    case 'message.block-delta': {
+      const messageIndex = snapshot.nodes.findIndex(
+        (node) => node.kind === 'message' && node.id === patch.messageId,
+      );
+      if (messageIndex < 0) return { missingTarget: `message:${patch.messageId}` };
+      const message = snapshot.nodes[messageIndex] as ConversationMessageNode;
+      const blockIndex = message.blocks.findIndex((block) => block.id === patch.blockId);
+      if (blockIndex < 0) return { missingTarget: `block:${patch.blockId}` };
+      const block = message.blocks[blockIndex];
+      if (block.kind === 'image') return { missingTarget: `text-block:${patch.blockId}` };
+      const blocks = [...message.blocks];
+      blocks[blockIndex] = { ...block, text: `${block.text}${patch.delta}` };
+      const nodes = [...snapshot.nodes];
+      nodes[messageIndex] = { ...message, blocks };
+      return { snapshot: { ...snapshot, nodes } };
+    }
+    case 'tool.upsert':
+      return { snapshot: { ...snapshot, nodes: upsertTool(snapshot.nodes, patch.node) } };
+    case 'compaction.upsert':
+    case 'boundary.upsert':
+    case 'subagent.upsert':
+      return { snapshot: { ...snapshot, nodes: upsertById(snapshot.nodes, patch.node) } };
+    case 'queue.replace':
+      return { snapshot: { ...snapshot, queue: clone(patch.queue) } };
+    case 'interaction.upsert': {
+      const index = snapshot.pendingInteractions.findIndex((item) => item.id === patch.interaction.id);
+      const pendingInteractions = [...snapshot.pendingInteractions];
+      if (index < 0) pendingInteractions.push(clone(patch.interaction));
+      else pendingInteractions[index] = clone(patch.interaction);
+      return { snapshot: { ...snapshot, pendingInteractions } };
+    }
+    case 'interaction.remove':
+      return {
+        snapshot: {
+          ...snapshot,
+          pendingInteractions: snapshot.pendingInteractions.filter(
+            (item) => item.id !== patch.interactionId,
+          ),
+        },
+      };
+    case 'context.replace':
+      return { snapshot: { ...snapshot, context: clone(patch.context) } };
+    case 'snapshot.invalidated':
+      return { missingTarget: patch.reason };
+    default:
+      return { missingTarget: 'unknown patch' };
+  }
+}
+
+export function reduceConversationPatch(
+  state: ConversationReducerState,
+  value: unknown,
+): ConversationReducerState {
+  if (state.invalidation) return state;
+  if (!state.snapshot) {
+    return invalidate(state, {
+      code: 'snapshot-required',
+      reason: 'A Conversation snapshot is required before live patches',
+    });
+  }
+
+  const envelope = parseEnvelopeShell(value);
+  if (!envelope) {
+    return invalidate(state, {
+      code: 'malformed-envelope',
+      reason: 'Conversation patch envelope is malformed',
+    });
+  }
+  if (envelope.conversationId !== state.snapshot.conversation.id) return state;
+
+  const currentGeneration = state.snapshot.cursor.workerGeneration;
+  if (envelope.workerGeneration < currentGeneration) return state;
+  if (envelope.workerGeneration > currentGeneration) {
+    return invalidate(state, {
+      code: 'generation-gap',
+      reason: 'A newer worker generation requires a fresh snapshot',
+      expectedGeneration: currentGeneration,
+      actualGeneration: envelope.workerGeneration,
+    });
+  }
+
+  const currentSeq = state.snapshot.cursor.seq;
+  if (envelope.seq <= currentSeq) return state;
+  if (envelope.seq !== currentSeq + 1) {
+    return invalidate(state, {
+      code: 'sequence-gap',
+      reason: 'Conversation patch sequence has a gap',
+      expectedSeq: currentSeq + 1,
+      actualSeq: envelope.seq,
+    });
+  }
+
+  const patchRecord = asRecord(envelope.patch);
+  if (!patchRecord || !PATCH_OPS.has(String(patchRecord.op))) {
+    return invalidate(state, {
+      code: 'unknown-patch',
+      reason: 'Conversation patch operation is not supported',
+    });
+  }
+  if (!isPatch(envelope.patch)) {
+    return invalidate(state, {
+      code: 'unknown-patch',
+      reason: 'Conversation patch payload does not match its operation',
+    });
+  }
+  if (envelope.patch.op === 'snapshot.invalidated') {
+    return invalidate(state, {
+      code: 'explicit-invalidation',
+      reason: envelope.patch.reason,
+    });
+  }
+
+  const applied = applyPatch(state.snapshot, envelope.patch);
+  if ('missingTarget' in applied) {
+    return invalidate(state, {
+      code: 'patch-target-missing',
+      reason: `Conversation patch target is missing: ${applied.missingTarget}`,
+    });
+  }
+  return {
+    snapshot: {
+      ...applied.snapshot,
+      cursor: {
+        ...applied.snapshot.cursor,
+        workerGeneration: envelope.workerGeneration,
+        seq: envelope.seq,
+      },
+    },
+    invalidation: null,
+  };
+}
diff --git a/shared/coding-conversation-subagent-protocol.ts b/shared/coding-conversation-subagent-protocol.ts
new file mode 100644
index 0000000..22e41e0
--- /dev/null
+++ b/shared/coding-conversation-subagent-protocol.ts
@@ -0,0 +1,82 @@
+import type { PublicUsage, SubagentDetailsV1 } from './coding-conversation-contracts';
+
+const STATUSES = new Set(['queued', 'running', 'complete', 'error', 'aborted', 'skipped']);
+
+function recordValue(value: unknown): Record<string, unknown> | null {
+  return value !== null && typeof value === 'object' && !Array.isArray(value)
+    ? value as Record<string, unknown>
+    : null;
+}
+
+function publicUsage(value: unknown): PublicUsage | undefined {
+  const usage = recordValue(value);
+  if (!usage
+    || typeof usage.inputTokens !== 'number'
+    || typeof usage.outputTokens !== 'number'
+    || !Number.isFinite(usage.inputTokens)
+    || !Number.isFinite(usage.outputTokens)
+    || usage.inputTokens < 0
+    || usage.outputTokens < 0
+    || (usage.cacheReadTokens !== undefined
+      && (typeof usage.cacheReadTokens !== 'number'
+        || !Number.isFinite(usage.cacheReadTokens)
+        || usage.cacheReadTokens < 0))
+    || (usage.cacheWriteTokens !== undefined
+      && (typeof usage.cacheWriteTokens !== 'number'
+        || !Number.isFinite(usage.cacheWriteTokens)
+        || usage.cacheWriteTokens < 0))) {
+    return undefined;
+  }
+  return {
+    inputTokens: usage.inputTokens,
+    outputTokens: usage.outputTokens,
+    ...(typeof usage.cacheReadTokens === 'number' ? { cacheReadTokens: usage.cacheReadTokens } : {}),
+    ...(typeof usage.cacheWriteTokens === 'number' ? { cacheWriteTokens: usage.cacheWriteTokens } : {}),
+  };
+}
+
+export function projectSubagentDetailsV1(value: unknown): SubagentDetailsV1 | undefined {
+  const record = recordValue(value);
+  if (!record
+    || record.schema !== 'subagent.v1'
+    || typeof record.dispatchId !== 'string'
+    || !record.dispatchId.trim()
+    || !['single', 'parallel', 'chain'].includes(String(record.mode))
+    || !Array.isArray(record.tasks)
+    || record.tasks.length === 0
+    || record.tasks.length > 8) return undefined;
+  const tasks: SubagentDetailsV1['tasks'] = [];
+  for (const value of record.tasks) {
+    const task = recordValue(value);
+    if (!task
+      || typeof task.taskId !== 'string'
+      || !task.taskId.trim()
+      || typeof task.agentId !== 'string'
+      || !task.agentId.trim()
+      || (task.toolProfile !== 'read-only' && task.toolProfile !== 'coding')
+      || !STATUSES.has(String(task.status))
+      || (task.summary !== undefined && typeof task.summary !== 'string')
+      || (task.errorCode !== undefined && typeof task.errorCode !== 'string')) return undefined;
+    const usage = task.usage === undefined ? undefined : publicUsage(task.usage);
+    if (task.usage !== undefined && !usage) return undefined;
+    tasks.push({
+      taskId: task.taskId,
+      agentId: task.agentId,
+      toolProfile: task.toolProfile,
+      status: task.status as SubagentDetailsV1['tasks'][number]['status'],
+      ...(typeof task.summary === 'string' ? { summary: task.summary.slice(0, 4_000) } : {}),
+      ...(typeof task.errorCode === 'string' ? { errorCode: task.errorCode.slice(0, 64) } : {}),
+      ...(usage ? { usage } : {}),
+    });
+  }
+  return {
+    schema: 'subagent.v1',
+    dispatchId: record.dispatchId,
+    mode: record.mode as SubagentDetailsV1['mode'],
+    tasks,
+  };
+}
+
+export function subagentDetailsOfResult(value: unknown): SubagentDetailsV1 | undefined {
+  return projectSubagentDetailsV1(recordValue(value)?.details);
+}
diff --git a/src/lib/coding-conversations.ts b/src/lib/coding-conversations.ts
new file mode 100644
index 0000000..6230eb3
--- /dev/null
+++ b/src/lib/coding-conversations.ts
@@ -0,0 +1,55 @@
+import type {
+  ConversationSnapshot,
+  PromptAcceptance,
+  PromptMode,
+} from '@/types/coding-conversation';
+import {
+  createHostEventSource,
+  ensureHostApiToken,
+  hostApiFetch,
+} from './host-api';
+
+export interface SubmitCodingConversationPromptInput {
+  conversationId: string;
+  clientRequestId: string;
+  mode: PromptMode;
+  text: string;
+  attachments: Array<{ attachmentId: string }>;
+}
+
+export async function getCodingConversationSnapshot(
+  conversationId: string,
+): Promise<ConversationSnapshot> {
+  const response = await hostApiFetch<{ snapshot: ConversationSnapshot }>(
+    `/api/coding/conversations/${encodeURIComponent(conversationId)}/snapshot`,
+  );
+  return response.snapshot;
+}
+
+export async function submitCodingConversationPrompt(
+  input: SubmitCodingConversationPromptInput,
+): Promise<PromptAcceptance> {
+  const response = await hostApiFetch<{ acceptance: PromptAcceptance }>(
+    `/api/coding/conversations/${encodeURIComponent(input.conversationId)}/prompt`,
+    {
+      method: 'POST',
+      body: JSON.stringify({
+        clientRequestId: input.clientRequestId,
+        mode: input.mode,
+        text: input.text,
+        attachments: input.attachments,
+      }),
+    },
+  );
+  return response.acceptance;
+}
+
+export async function openCodingConversationEvents(
+  conversationId?: string,
+): Promise<EventSource> {
+  await ensureHostApiToken();
+  const params = new URLSearchParams();
+  if (conversationId) params.set('conversationId', conversationId);
+  const query = params.toString();
+  return createHostEventSource(`/api/coding/events${query ? `?${query}` : ''}`);
+}
diff --git a/src/stores/coding-conversations.ts b/src/stores/coding-conversations.ts
new file mode 100644
index 0000000..e35386d
--- /dev/null
+++ b/src/stores/coding-conversations.ts
@@ -0,0 +1,657 @@
+import { useStore } from 'zustand';
+import { createStore, type StoreApi } from 'zustand/vanilla';
+import {
+  createConversationReducerState,
+  reduceConversationPatch,
+  replaceConversationSnapshot,
+  type ConversationReducerState,
+} from '../../shared/coding-conversation-reducer';
+import { AppError } from '@/lib/error-model';
+import {
+  getCodingConversationSnapshot,
+  openCodingConversationEvents,
+  submitCodingConversationPrompt,
+  type SubmitCodingConversationPromptInput,
+} from '@/lib/coding-conversations';
+import type {
+  CodingConversationDraft,
+  CodingConversationPatchEvent,
+  CodingConversationSnapshotEvent,
+  CodingConversationSummary,
+  CodingDraftAttachment,
+  CodingPromptRequestState,
+  ConversationMessageNode,
+  ConversationPatchEnvelope,
+  ConversationSnapshot,
+  PromptAcceptance,
+  PromptMode,
+} from '@/types/coding-conversation';
+
+export type CodingConversationLoadState =
+  | 'empty'
+  | 'loading'
+  | 'live'
+  | 'recovering'
+  | 'error';
+
+export interface CodingConversationEntry {
+  reducer: ConversationReducerState;
+  loadState: CodingConversationLoadState;
+  error: string | null;
+  unread: boolean;
+}
+
+export interface SubmitCodingPromptInput {
+  conversationId: string;
+  mode: PromptMode;
+  text?: string;
+  attachments?: CodingDraftAttachment[];
+}
+
+interface CodingConversationStoreDependencies {
+  getSnapshot(conversationId: string): Promise<ConversationSnapshot>;
+  openEvents(conversationId?: string): Promise<EventSource>;
+  submitPrompt(input: SubmitCodingConversationPromptInput): Promise<PromptAcceptance>;
+  createId(kind: 'request' | 'node'): string;
+}
+
+export interface CodingConversationStoreState {
+  selectedConversationId: string | null;
+  entriesByConversationId: Record<string, CodingConversationEntry>;
+  summariesByConversationId: Record<string, CodingConversationSummary>;
+  draftsByConversationId: Record<string, CodingConversationDraft>;
+  requestsByConversationId: Record<string, Record<string, CodingPromptRequestState>>;
+  connectionState: 'disconnected' | 'connecting' | 'live' | 'reconnecting' | 'error';
+  globalError: string | null;
+  selectConversation(conversationId: string): Promise<void>;
+  loadSnapshot(conversationId: string, recovering?: boolean): Promise<ConversationSnapshot>;
+  connectEvents(): Promise<void>;
+  disconnectEvents(): void;
+  setDraft(conversationId: string, text: string, attachments?: CodingDraftAttachment[]): void;
+  markUnread(conversationId: string, unread: boolean): void;
+  submitPrompt(input: SubmitCodingPromptInput): Promise<PromptAcceptance>;
+  applySnapshotEvent(event: CodingConversationSnapshotEvent): void;
+  applyPatchEvent(event: CodingConversationPatchEvent): void;
+}
+
+const DEFAULT_DRAFT: CodingConversationDraft = {
+  text: '',
+  attachments: [],
+  revision: 0,
+};
+const EMPTY_REQUESTS: Record<string, CodingPromptRequestState> = {};
+
+function cloneDraft(draft: CodingConversationDraft): CodingConversationDraft {
+  return {
+    text: draft.text,
+    attachments: draft.attachments.map((attachment) => ({ ...attachment })),
+    revision: draft.revision,
+  };
+}
+
+function emptyEntry(): CodingConversationEntry {
+  return {
+    reducer: createConversationReducerState(),
+    loadState: 'empty',
+    error: null,
+    unread: false,
+  };
+}
+
+function errorDetails(error: unknown): { code?: string; message: string } {
+  if (error instanceof AppError) {
+    return {
+      ...(typeof error.details?.backendCode === 'string'
+        ? { code: error.details.backendCode }
+        : {}),
+      message: error.message,
+    };
+  }
+  return { message: error instanceof Error ? error.message : String(error) };
+}
+
+function summaryOf(entry: CodingConversationEntry): CodingConversationSummary | null {
+  const snapshot = entry.reducer.snapshot;
+  if (!snapshot) return null;
+  return {
+    conversationId: snapshot.conversation.id,
+    title: snapshot.conversation.title,
+    runStatus: snapshot.run.status,
+    runError: snapshot.run.error ?? null,
+    workerStatus: snapshot.worker.status,
+    model: snapshot.conversation.model,
+    unread: entry.unread,
+  };
+}
+
+function summariesWithEntry(
+  summaries: Record<string, CodingConversationSummary>,
+  entry: CodingConversationEntry,
+): Record<string, CodingConversationSummary> {
+  const next = summaryOf(entry);
+  if (!next) return summaries;
+  const current = summaries[next.conversationId];
+  if (current
+    && current.title === next.title
+    && current.runStatus === next.runStatus
+    && current.runError === next.runError
+    && current.workerStatus === next.workerStatus
+    && current.model === next.model
+    && current.unread === next.unread) {
+    return summaries;
+  }
+  return { ...summaries, [next.conversationId]: next };
+}
+
+function requestIdsInSnapshot(snapshot: ConversationSnapshot): Set<string> {
+  return new Set(snapshot.nodes.flatMap((node) => (
+    node.kind === 'message' && node.clientRequestId ? [node.clientRequestId] : []
+  )));
+}
+
+function withoutReconciledRequests(
+  requests: Record<string, CodingPromptRequestState> | undefined,
+  snapshot: ConversationSnapshot,
+): Record<string, CodingPromptRequestState> {
+  const reconciled = requestIdsInSnapshot(snapshot);
+  if (!requests || reconciled.size === 0) return requests ?? {};
+  return Object.fromEntries(
+    Object.entries(requests).filter(([clientRequestId]) => !reconciled.has(clientRequestId)),
+  );
+}
+
+function optimisticNode(
+  nodeId: string,
+  clientRequestId: string,
+  draft: CodingConversationDraft,
+): ConversationMessageNode {
+  return {
+    kind: 'message',
+    id: nodeId,
+    clientRequestId,
+    role: 'user',
+    status: 'optimistic',
+    blocks: [
+      ...(draft.text ? [{
+        kind: 'text' as const,
+        id: `${nodeId}:text`,
+        text: draft.text,
+        status: 'complete' as const,
+      }] : []),
+      ...draft.attachments.map((attachment, index) => ({
+        kind: 'image' as const,
+        id: `${nodeId}:attachment:${index}`,
+        attachmentId: attachment.attachmentId,
+        mime: attachment.mime,
+      })),
+    ],
+  };
+}
+
+function withOptimisticNode(
+  reducer: ConversationReducerState,
+  node: ConversationMessageNode,
+): ConversationReducerState {
+  const snapshot = reducer.snapshot;
+  if (!snapshot) return reducer;
+  return replaceConversationSnapshot(reducer, {
+    ...snapshot,
+    nodes: [...snapshot.nodes, node],
+  });
+}
+
+function withRejectedNode(
+  reducer: ConversationReducerState,
+  nodeId: string | undefined,
+): ConversationReducerState {
+  const snapshot = reducer.snapshot;
+  if (!snapshot || !nodeId) return reducer;
+  return replaceConversationSnapshot(reducer, {
+    ...snapshot,
+    nodes: snapshot.nodes.map((node) => (
+      node.kind === 'message' && node.id === nodeId
+        ? { ...node, status: 'error' as const }
+        : node
+    )),
+  });
+}
+
+function snapshotIsOlder(
+  current: ConversationSnapshot | null,
+  incoming: ConversationSnapshot,
+): boolean {
+  if (!current) return false;
+  if (incoming.cursor.workerGeneration !== current.cursor.workerGeneration) {
+    return incoming.cursor.workerGeneration < current.cursor.workerGeneration;
+  }
+  return incoming.cursor.seq < current.cursor.seq;
+}
+
+function defaultDependencies(): CodingConversationStoreDependencies {
+  return {
+    getSnapshot: getCodingConversationSnapshot,
+    openEvents: openCodingConversationEvents,
+    submitPrompt: submitCodingConversationPrompt,
+    createId: () => crypto.randomUUID(),
+  };
+}
+
+export function createCodingConversationStore(
+  dependencies: Partial<CodingConversationStoreDependencies> = {},
+): StoreApi<CodingConversationStoreState> {
+  const deps = { ...defaultDependencies(), ...dependencies };
+  const snapshotLoads = new Map<string, Promise<ConversationSnapshot>>();
+  let eventSource: EventSource | null = null;
+  let connectFlight: Promise<void> | null = null;
+  let connectionGeneration = 0;
+
+  return createStore<CodingConversationStoreState>((set, get) => ({
+    selectedConversationId: null,
+    entriesByConversationId: {},
+    summariesByConversationId: {},
+    draftsByConversationId: {},
+    requestsByConversationId: {},
+    connectionState: 'disconnected',
+    globalError: null,
+
+    async selectConversation(conversationId) {
+      set((state) => {
+        const current = state.entriesByConversationId[conversationId] ?? emptyEntry();
+        const entry = current.unread ? { ...current, unread: false } : current;
+        return {
+          selectedConversationId: conversationId,
+          entriesByConversationId: {
+            ...state.entriesByConversationId,
+            [conversationId]: entry,
+          },
+          summariesByConversationId: summariesWithEntry(state.summariesByConversationId, entry),
+        };
+      });
+      const entry = get().entriesByConversationId[conversationId];
+      if (!entry?.reducer.snapshot || entry.reducer.invalidation) {
+        await get().loadSnapshot(conversationId, Boolean(entry?.reducer.invalidation));
+      }
+      await get().connectEvents();
+    },
+
+    loadSnapshot(conversationId, recovering = false) {
+      const prior = snapshotLoads.get(conversationId);
+      if (prior) return prior;
+      set((state) => {
+        const entry = state.entriesByConversationId[conversationId] ?? emptyEntry();
+        return {
+          entriesByConversationId: {
+            ...state.entriesByConversationId,
+            [conversationId]: {
+              ...entry,
+              loadState: recovering ? 'recovering' : 'loading',
+              error: null,
+            },
+          },
+        };
+      });
+      const flight = deps.getSnapshot(conversationId)
+        .then((snapshot) => {
+          get().applySnapshotEvent({
+            type: 'snapshot',
+            conversationId,
+            workerGeneration: snapshot.cursor.workerGeneration,
+            seq: snapshot.cursor.seq,
+            snapshot,
+          });
+          return snapshot;
+        })
+        .catch((error) => {
+          const failure = errorDetails(error);
+          set((state) => {
+            const entry = state.entriesByConversationId[conversationId] ?? emptyEntry();
+            return {
+              entriesByConversationId: {
+                ...state.entriesByConversationId,
+                [conversationId]: { ...entry, loadState: 'error', error: failure.message },
+              },
+            };
+          });
+          throw error;
+        })
+        .finally(() => {
+          if (snapshotLoads.get(conversationId) === flight) snapshotLoads.delete(conversationId);
+        });
+      snapshotLoads.set(conversationId, flight);
+      return flight;
+    },
+
+    async connectEvents() {
+      if (eventSource) return;
+      if (connectFlight) return await connectFlight;
+      const generation = ++connectionGeneration;
+      set({ connectionState: 'connecting', globalError: null });
+      let flight: Promise<void>;
+      flight = deps.openEvents()
+        .then((source) => {
+          if (generation !== connectionGeneration) {
+            source.close();
+            return;
+          }
+          eventSource = source;
+          const parse = <T,>(event: Event): T => JSON.parse((event as MessageEvent<string>).data) as T;
+          source.addEventListener('snapshot', (event) => {
+            try {
+              get().applySnapshotEvent(parse<CodingConversationSnapshotEvent>(event));
+            } catch {
+              set({ connectionState: 'error', globalError: 'Conversation 事件快照无法读取。' });
+            }
+          });
+          source.addEventListener('patch', (event) => {
+            try {
+              get().applyPatchEvent(parse<CodingConversationPatchEvent>(event));
+            } catch {
+              set({ connectionState: 'error', globalError: 'Conversation 事件更新无法读取。' });
+            }
+          });
+          source.onopen = () => {
+            if (eventSource === source) set({ connectionState: 'live', globalError: null });
+          };
+          source.onerror = () => {
+            if (eventSource === source) {
+              set({
+                connectionState: 'reconnecting',
+                globalError: 'Conversation 事件连接中断，正在重连。',
+              });
+            }
+          };
+        })
+        .catch((error) => {
+          if (generation !== connectionGeneration) return;
+          set({ connectionState: 'error', globalError: errorDetails(error).message });
+          throw error;
+        })
+        .finally(() => {
+          if (connectFlight === flight) connectFlight = null;
+        });
+      connectFlight = flight;
+      await flight;
+    },
+
+    disconnectEvents() {
+      connectionGeneration += 1;
+      eventSource?.close();
+      eventSource = null;
+      connectFlight = null;
+      set({ connectionState: 'disconnected', globalError: null });
+    },
+
+    setDraft(conversationId, text, attachments = []) {
+      set((state) => {
+        const current = state.draftsByConversationId[conversationId] ?? DEFAULT_DRAFT;
+        return {
+          draftsByConversationId: {
+            ...state.draftsByConversationId,
+            [conversationId]: {
+              text,
+              attachments: attachments.map((attachment) => ({ ...attachment })),
+              revision: current.revision + 1,
+            },
+          },
+        };
+      });
+    },
+
+    markUnread(conversationId, unread) {
+      set((state) => {
+        const current = state.entriesByConversationId[conversationId] ?? emptyEntry();
+        if (current.unread === unread) return state;
+        const entry = { ...current, unread };
+        return {
+          entriesByConversationId: {
+            ...state.entriesByConversationId,
+            [conversationId]: entry,
+          },
+          summariesByConversationId: summariesWithEntry(state.summariesByConversationId, entry),
+        };
+      });
+    },
+
+    async submitPrompt(input) {
+      let entry = get().entriesByConversationId[input.conversationId];
+      if (!entry?.reducer.snapshot || entry.reducer.invalidation) {
+        await get().loadSnapshot(input.conversationId, Boolean(entry?.reducer.invalidation));
+        entry = get().entriesByConversationId[input.conversationId];
+      }
+      if (!entry?.reducer.snapshot) throw new Error('Conversation snapshot is unavailable');
+
+      const existingDraft = get().draftsByConversationId[input.conversationId] ?? DEFAULT_DRAFT;
+      const submittedDraft: CodingConversationDraft = {
+        text: input.text ?? existingDraft.text,
+        attachments: (input.attachments ?? existingDraft.attachments).map((attachment) => ({ ...attachment })),
+        revision: existingDraft.revision,
+      };
+      const clientRequestId = deps.createId('request');
+      const nodeId = input.mode === 'prompt' ? deps.createId('node') : undefined;
+      const clearedRevision = existingDraft.revision + 1;
+      const request: CodingPromptRequestState = {
+        clientRequestId,
+        mode: input.mode,
+        ...(nodeId ? { nodeId } : {}),
+        status: 'pending',
+        submittedDraft: cloneDraft(submittedDraft),
+      };
+
+      set((state) => {
+        const currentEntry = state.entriesByConversationId[input.conversationId] ?? emptyEntry();
+        const reducer = nodeId
+          ? withOptimisticNode(
+              currentEntry.reducer,
+              optimisticNode(nodeId, clientRequestId, submittedDraft),
+            )
+          : currentEntry.reducer;
+        const nextEntry = { ...currentEntry, reducer, error: null };
+        return {
+          entriesByConversationId: {
+            ...state.entriesByConversationId,
+            [input.conversationId]: nextEntry,
+          },
+          summariesByConversationId: summariesWithEntry(
+            state.summariesByConversationId,
+            nextEntry,
+          ),
+          draftsByConversationId: {
+            ...state.draftsByConversationId,
+            [input.conversationId]: { text: '', attachments: [], revision: clearedRevision },
+          },
+          requestsByConversationId: {
+            ...state.requestsByConversationId,
+            [input.conversationId]: {
+              ...(state.requestsByConversationId[input.conversationId] ?? {}),
+              [clientRequestId]: request,
+            },
+          },
+        };
+      });
+
+      try {
+        const acceptance = await deps.submitPrompt({
+          conversationId: input.conversationId,
+          clientRequestId,
+          mode: input.mode,
+          text: submittedDraft.text,
+          attachments: submittedDraft.attachments.map(({ attachmentId }) => ({ attachmentId })),
+        });
+        set((state) => {
+          const requests = state.requestsByConversationId[input.conversationId] ?? {};
+          const current = requests[clientRequestId];
+          if (!current) return state;
+          return {
+            requestsByConversationId: {
+              ...state.requestsByConversationId,
+              [input.conversationId]: {
+                ...requests,
+                [clientRequestId]: { ...current, status: 'accepted' },
+              },
+            },
+          };
+        });
+        return acceptance;
+      } catch (error) {
+        const failure = errorDetails(error);
+        const uncertain = failure.code === 'CODING_REQUEST_UNCERTAIN';
+        set((state) => {
+          const currentEntry = state.entriesByConversationId[input.conversationId] ?? emptyEntry();
+          const requests = state.requestsByConversationId[input.conversationId] ?? {};
+          const currentRequest = requests[clientRequestId] ?? request;
+          const currentDraft = state.draftsByConversationId[input.conversationId] ?? DEFAULT_DRAFT;
+          const canRestore = currentDraft.revision === clearedRevision
+            && !currentDraft.text
+            && currentDraft.attachments.length === 0;
+          const reducer = uncertain
+            ? currentEntry.reducer
+            : withRejectedNode(currentEntry.reducer, nodeId);
+          const nextEntry = { ...currentEntry, reducer, error: failure.message };
+          return {
+            entriesByConversationId: {
+              ...state.entriesByConversationId,
+              [input.conversationId]: nextEntry,
+            },
+            summariesByConversationId: summariesWithEntry(
+              state.summariesByConversationId,
+              nextEntry,
+            ),
+            draftsByConversationId: canRestore
+              ? {
+                  ...state.draftsByConversationId,
+                  [input.conversationId]: {
+                    ...cloneDraft(submittedDraft),
+                    revision: clearedRevision + 1,
+                  },
+                }
+              : state.draftsByConversationId,
+            requestsByConversationId: {
+              ...state.requestsByConversationId,
+              [input.conversationId]: {
+                ...requests,
+                [clientRequestId]: {
+                  ...currentRequest,
+                  status: uncertain ? 'uncertain' : 'rejected',
+                  ...(failure.code ? { errorCode: failure.code } : {}),
+                  errorMessage: failure.message,
+                },
+              },
+            },
+          };
+        });
+        throw error;
+      }
+    },
+
+    applySnapshotEvent(event) {
+      const snapshot = event.snapshot;
+      if (event.type !== 'snapshot'
+        || event.conversationId !== snapshot.conversation.id
+        || event.workerGeneration !== snapshot.cursor.workerGeneration
+        || event.seq !== snapshot.cursor.seq) {
+        return;
+      }
+      set((state) => {
+        const current = state.entriesByConversationId[event.conversationId] ?? emptyEntry();
+        if (!current.reducer.invalidation && snapshotIsOlder(current.reducer.snapshot, snapshot)) {
+          return state;
+        }
+        const reducer = replaceConversationSnapshot(current.reducer, snapshot);
+        const entry: CodingConversationEntry = {
+          ...current,
+          reducer,
+          loadState: reducer.invalidation ? 'error' : 'live',
+          error: reducer.invalidation?.reason ?? null,
+          unread: state.selectedConversationId === event.conversationId ? false : current.unread,
+        };
+        return {
+          entriesByConversationId: {
+            ...state.entriesByConversationId,
+            [event.conversationId]: entry,
+          },
+          summariesByConversationId: summariesWithEntry(state.summariesByConversationId, entry),
+          requestsByConversationId: {
+            ...state.requestsByConversationId,
+            [event.conversationId]: withoutReconciledRequests(
+              state.requestsByConversationId[event.conversationId],
+              snapshot,
+            ),
+          },
+        };
+      });
+    },
+
+    applyPatchEvent(event) {
+      if (event.type !== 'patch') return;
+      let recover = false;
+      set((state) => {
+        const current = state.entriesByConversationId[event.conversationId] ?? emptyEntry();
+        const reducer = reduceConversationPatch(current.reducer, event as ConversationPatchEnvelope);
+        if (reducer === current.reducer) return state;
+        recover = Boolean(reducer.invalidation);
+        const incomingMessage = event.patch.op === 'message.upsert' ? event.patch.node : null;
+        const unread = state.selectedConversationId !== event.conversationId
+          && incomingMessage?.role === 'assistant'
+            ? true
+            : current.unread;
+        const entry: CodingConversationEntry = {
+          ...current,
+          reducer,
+          loadState: reducer.invalidation ? 'recovering' : 'live',
+          error: reducer.invalidation?.reason ?? null,
+          unread,
+        };
+        const requests = state.requestsByConversationId[event.conversationId] ?? {};
+        const nextRequests = incomingMessage?.clientRequestId
+          ? Object.fromEntries(
+              Object.entries(requests).filter(([id]) => id !== incomingMessage.clientRequestId),
+            )
+          : requests;
+        return {
+          entriesByConversationId: {
+            ...state.entriesByConversationId,
+            [event.conversationId]: entry,
+          },
+          summariesByConversationId: summariesWithEntry(state.summariesByConversationId, entry),
+          requestsByConversationId: nextRequests === requests
+            ? state.requestsByConversationId
+            : {
+                ...state.requestsByConversationId,
+                [event.conversationId]: nextRequests,
+              },
+        };
+      });
+      if (recover) {
+        void get().loadSnapshot(event.conversationId, true).catch(() => undefined);
+      }
+    },
+  }));
+}
+
+export const codingConversationStore = createCodingConversationStore();
+
+export function useCodingConversationStore<T>(
+  selector: (state: CodingConversationStoreState) => T,
+): T {
+  return useStore(codingConversationStore, selector);
+}
+
+export const selectCodingConversationSnapshot = (conversationId: string) => (
+  state: CodingConversationStoreState,
+): ConversationSnapshot | null => (
+  state.entriesByConversationId[conversationId]?.reducer.snapshot ?? null
+);
+
+export const selectCodingConversationSummary = (conversationId: string) => (
+  state: CodingConversationStoreState,
+): CodingConversationSummary | null => state.summariesByConversationId[conversationId] ?? null;
+
+export const selectCodingConversationDraft = (conversationId: string) => (
+  state: CodingConversationStoreState,
+): CodingConversationDraft => state.draftsByConversationId[conversationId] ?? DEFAULT_DRAFT;
+
+export const selectCodingConversationRequests = (conversationId: string) => (
+  state: CodingConversationStoreState,
+): Record<string, CodingPromptRequestState> => (
+  state.requestsByConversationId[conversationId] ?? EMPTY_REQUESTS
+);
diff --git a/src/types/coding-conversation.ts b/src/types/coding-conversation.ts
new file mode 100644
index 0000000..3e50b9a
--- /dev/null
+++ b/src/types/coding-conversation.ts
@@ -0,0 +1,77 @@
+export type {
+  CodingRuntimePublicError,
+  ConversationMessageNode,
+  ConversationModelState,
+  ConversationNode,
+  ConversationPatch,
+  ConversationPatchEnvelope,
+  ConversationQueueState,
+  ConversationRunState,
+  ConversationRunStatus,
+  ConversationSnapshot,
+  ConversationThinkingLevel,
+  ProductModelRef,
+  PromptAcceptance,
+  PromptMode,
+  PublicWorkerState,
+} from '../../shared/coding-conversation-contracts';
+
+import type {
+  ConversationPatchEnvelope,
+  ConversationSnapshot,
+  PromptMode,
+} from '../../shared/coding-conversation-contracts';
+
+export interface CodingConversationSnapshotEvent {
+  type: 'snapshot';
+  conversationId: string;
+  workerGeneration: number;
+  seq: number;
+  snapshot: ConversationSnapshot;
+}
+
+export type CodingConversationPatchEvent = {
+  type: 'patch';
+} & ConversationPatchEnvelope;
+
+export type CodingConversationStreamEvent =
+  | CodingConversationSnapshotEvent
+  | CodingConversationPatchEvent;
+
+export interface CodingDraftAttachment {
+  attachmentId: string;
+  mime: string;
+  previewUrl?: string;
+}
+
+export interface CodingConversationDraft {
+  text: string;
+  attachments: CodingDraftAttachment[];
+  revision: number;
+}
+
+export type CodingPromptRequestStatus =
+  | 'pending'
+  | 'accepted'
+  | 'rejected'
+  | 'uncertain';
+
+export interface CodingPromptRequestState {
+  clientRequestId: string;
+  mode: PromptMode;
+  nodeId?: string;
+  status: CodingPromptRequestStatus;
+  submittedDraft: CodingConversationDraft;
+  errorCode?: string;
+  errorMessage?: string;
+}
+
+export interface CodingConversationSummary {
+  conversationId: string;
+  title: string;
+  runStatus: ConversationSnapshot['run']['status'];
+  runError: ConversationSnapshot['run']['error'] | null;
+  workerStatus: ConversationSnapshot['worker']['status'];
+  model: ConversationSnapshot['conversation']['model'];
+  unread: boolean;
+}
diff --git a/tests/unit/coding-conversations-facade.test.ts b/tests/unit/coding-conversations-facade.test.ts
new file mode 100644
index 0000000..1f87e82
--- /dev/null
+++ b/tests/unit/coding-conversations-facade.test.ts
@@ -0,0 +1,82 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const hostApi = vi.hoisted(() => ({
+  fetch: vi.fn(),
+  ensureToken: vi.fn(),
+  createEvents: vi.fn(),
+}));
+
+vi.mock('@/lib/host-api', () => ({
+  hostApiFetch: hostApi.fetch,
+  ensureHostApiToken: hostApi.ensureToken,
+  createHostEventSource: hostApi.createEvents,
+}));
+
+describe('coding Conversations Host facade', () => {
+  beforeEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('loads the target snapshot through the encoded Host route', async () => {
+    const snapshot = { conversation: { id: 'conversation/a' } };
+    hostApi.fetch.mockResolvedValueOnce({ snapshot });
+    const { getCodingConversationSnapshot } = await import('@/lib/coding-conversations');
+
+    await expect(getCodingConversationSnapshot('conversation/a')).resolves.toBe(snapshot);
+    expect(hostApi.fetch).toHaveBeenCalledWith(
+      '/api/coding/conversations/conversation%2Fa/snapshot',
+    );
+  });
+
+  it('submits only the product prompt DTO and returns its acceptance', async () => {
+    const acceptance = {
+      accepted: true,
+      conversationId: 'conversation/a',
+      clientRequestId: 'request-1',
+      runId: 'run-1',
+      mode: 'prompt',
+    };
+    hostApi.fetch.mockResolvedValueOnce({ acceptance });
+    const { submitCodingConversationPrompt } = await import('@/lib/coding-conversations');
+
+    await expect(submitCodingConversationPrompt({
+      conversationId: 'conversation/a',
+      clientRequestId: 'request-1',
+      mode: 'prompt',
+      text: 'Build it',
+      attachments: [{ attachmentId: 'attachment-1' }],
+    })).resolves.toBe(acceptance);
+    expect(hostApi.fetch).toHaveBeenCalledWith(
+      '/api/coding/conversations/conversation%2Fa/prompt',
+      {
+        method: 'POST',
+        body: JSON.stringify({
+          clientRequestId: 'request-1',
+          mode: 'prompt',
+          text: 'Build it',
+          attachments: [{ attachmentId: 'attachment-1' }],
+        }),
+      },
+    );
+  });
+
+  it('hydrates the Host token before constructing the EventSource URL', async () => {
+    const order: string[] = [];
+    const source = { close: vi.fn() } as unknown as EventSource;
+    hostApi.ensureToken.mockImplementationOnce(async () => {
+      order.push('token');
+      return 'host-token';
+    });
+    hostApi.createEvents.mockImplementationOnce((path: string) => {
+      order.push(`events:${path}`);
+      return source;
+    });
+    const { openCodingConversationEvents } = await import('@/lib/coding-conversations');
+
+    await expect(openCodingConversationEvents('conversation/a')).resolves.toBe(source);
+    expect(order).toEqual([
+      'token',
+      'events:/api/coding/events?conversationId=conversation%2Fa',
+    ]);
+  });
+});
diff --git a/tests/unit/coding-conversations-store.test.tsx b/tests/unit/coding-conversations-store.test.tsx
new file mode 100644
index 0000000..85b4ec6
--- /dev/null
+++ b/tests/unit/coding-conversations-store.test.tsx
@@ -0,0 +1,443 @@
+import { act, renderHook, waitFor } from '@testing-library/react';
+import { readFile } from 'node:fs/promises';
+import { fileURLToPath } from 'node:url';
+import { useStore } from 'zustand';
+import { describe, expect, it, vi } from 'vitest';
+import { AppError } from '@/lib/error-model';
+import {
+  createCodingConversationStore,
+  selectCodingConversationSnapshot,
+} from '@/stores/coding-conversations';
+import type {
+  CodingConversationPatchEvent,
+  CodingConversationSnapshotEvent,
+  ConversationPatch,
+  ConversationSnapshot,
+  PromptAcceptance,
+} from '@/types/coding-conversation';
+import { createProductSnapshot } from '../fixtures/coding-conversation-product-fixtures';
+
+class FakeEventSource {
+  onopen: ((event: Event) => void) | null = null;
+  onerror: ((event: Event) => void) | null = null;
+  readonly close = vi.fn();
+  private readonly listeners = new Map<string, Set<EventListenerOrEventListenerObject>>();
+
+  addEventListener(type: string, listener: EventListenerOrEventListenerObject): void {
+    const listeners = this.listeners.get(type) ?? new Set();
+    listeners.add(listener);
+    this.listeners.set(type, listeners);
+  }
+
+  emit(type: 'snapshot' | 'patch', value: unknown): void {
+    const event = new MessageEvent(type, { data: JSON.stringify(value) });
+    for (const listener of this.listeners.get(type) ?? []) {
+      if (typeof listener === 'function') listener(event);
+      else listener.handleEvent(event);
+    }
+  }
+
+  open(): void {
+    this.onopen?.(new Event('open'));
+  }
+
+  fail(): void {
+    this.onerror?.(new Event('error'));
+  }
+}
+
+function snapshot(
+  conversationId: string,
+  workerGeneration = 1,
+  seq = 0,
+): ConversationSnapshot {
+  const value = createProductSnapshot(conversationId, workerGeneration);
+  return {
+    ...value,
+    conversation: {
+      ...value.conversation,
+      title: `Conversation ${conversationId}`,
+    },
+    cursor: { ...value.cursor, seq },
+  };
+}
+
+function snapshotEvent(value: ConversationSnapshot): CodingConversationSnapshotEvent {
+  return {
+    type: 'snapshot',
+    conversationId: value.conversation.id,
+    workerGeneration: value.cursor.workerGeneration,
+    seq: value.cursor.seq,
+    snapshot: value,
+  };
+}
+
+function patchEvent(
+  conversationId: string,
+  seq: number,
+  patch: ConversationPatch,
+  workerGeneration = 1,
+): CodingConversationPatchEvent {
+  return {
+    type: 'patch',
+    conversationId,
+    workerGeneration,
+    seq,
+    at: 1_000 + seq,
+    patch,
+  };
+}
+
+function acceptance(
+  conversationId: string,
+  clientRequestId: string,
+): PromptAcceptance {
+  return {
+    accepted: true,
+    conversationId,
+    clientRequestId,
+    runId: 'run-1',
+    mode: 'prompt',
+  };
+}
+
+function deferred<T>() {
+  let resolve!: (value: T) => void;
+  let reject!: (reason?: unknown) => void;
+  const promise = new Promise<T>((resolvePromise, rejectPromise) => {
+    resolve = resolvePromise;
+    reject = rejectPromise;
+  });
+  return { promise, resolve, reject };
+}
+
+function ids() {
+  const counters = { request: 0, node: 0 };
+  return (kind: 'request' | 'node') => `${kind}-${++counters[kind]}`;
+}
+
+describe('coding Conversation store', () => {
+  it('isolates interleaved snapshot and patch state for two Conversations', async () => {
+    const source = new FakeEventSource();
+    const getSnapshot = vi.fn(async (conversationId: string) => snapshot(conversationId));
+    const store = createCodingConversationStore({
+      getSnapshot,
+      openEvents: vi.fn(async () => source as unknown as EventSource),
+      submitPrompt: vi.fn(),
+      createId: ids(),
+    });
+
+    await store.getState().selectConversation('conversation-a');
+    source.open();
+    source.emit('snapshot', snapshotEvent(snapshot('conversation-b')));
+    const aBeforeB = selectCodingConversationSnapshot('conversation-a')(store.getState());
+
+    source.emit('patch', patchEvent('conversation-a', 1, {
+      op: 'run.state',
+      run: { status: 'running', runId: 'run-a', mode: 'prompt' },
+    }));
+    const aAfterOwnPatch = selectCodingConversationSnapshot('conversation-a')(store.getState());
+    source.emit('patch', patchEvent('conversation-b', 1, {
+      op: 'message.upsert',
+      node: {
+        kind: 'message',
+        id: 'assistant-b',
+        role: 'assistant',
+        status: 'streaming',
+        blocks: [{ kind: 'text', id: 'text-b', text: 'B', status: 'streaming' }],
+      },
+    }));
+
+    expect(aBeforeB?.run.status).toBe('idle');
+    expect(aAfterOwnPatch?.run.status).toBe('running');
+    expect(selectCodingConversationSnapshot('conversation-a')(store.getState()))
+      .toBe(aAfterOwnPatch);
+    expect(selectCodingConversationSnapshot('conversation-b')(store.getState())?.nodes)
+      .toHaveLength(1);
+    expect(store.getState().summariesByConversationId['conversation-a'].unread).toBe(false);
+    expect(store.getState().summariesByConversationId['conversation-b'].unread).toBe(true);
+    expect(getSnapshot).toHaveBeenCalledTimes(1);
+    expect(store.getState().connectionState).toBe('live');
+  });
+
+  it('refreshes only the gapped target and drops an older worker generation', async () => {
+    const recoveredA = snapshot('conversation-a', 1, 2);
+    const getSnapshot = vi.fn(async (conversationId: string) => {
+      expect(conversationId).toBe('conversation-a');
+      return recoveredA;
+    });
+    const store = createCodingConversationStore({
+      getSnapshot,
+      openEvents: vi.fn(),
+      submitPrompt: vi.fn(),
+      createId: ids(),
+    });
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-a')));
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-b')));
+    const bBefore = selectCodingConversationSnapshot('conversation-b')(store.getState());
+
+    store.getState().applyPatchEvent(patchEvent('conversation-b', 1, {
+      op: 'run.state',
+      run: { status: 'running' },
+    }, 0));
+    store.getState().applyPatchEvent(patchEvent('conversation-a', 2, {
+      op: 'run.state',
+      run: { status: 'running' },
+    }));
+
+    await waitFor(() => {
+      expect(getSnapshot).toHaveBeenCalledTimes(1);
+      expect(store.getState().entriesByConversationId['conversation-a'].loadState).toBe('live');
+    });
+    expect(selectCodingConversationSnapshot('conversation-a')(store.getState())?.cursor.seq).toBe(2);
+    expect(selectCodingConversationSnapshot('conversation-b')(store.getState())).toBe(bBefore);
+    expect(store.getState().entriesByConversationId['conversation-b'].reducer.invalidation).toBeNull();
+  });
+
+  it('uses native EventSource reconnect without reopening or replaying a mutation', async () => {
+    const source = new FakeEventSource();
+    const openEvents = vi.fn(async () => source as unknown as EventSource);
+    const submitPrompt = vi.fn(async (input) => acceptance(input.conversationId, input.clientRequestId));
+    const store = createCodingConversationStore({
+      getSnapshot: vi.fn(async (conversationId: string) => snapshot(conversationId)),
+      openEvents,
+      submitPrompt,
+      createId: ids(),
+    });
+    await store.getState().selectConversation('conversation-a');
+    store.getState().setDraft('conversation-a', 'one request');
+    await store.getState().submitPrompt({ conversationId: 'conversation-a', mode: 'prompt' });
+
+    source.fail();
+    expect(store.getState().connectionState).toBe('reconnecting');
+    source.open();
+
+    expect(store.getState().connectionState).toBe('live');
+    expect(openEvents).toHaveBeenCalledTimes(1);
+    expect(submitPrompt).toHaveBeenCalledTimes(1);
+  });
+
+  it('does not let a cancelled connection clear a newer connection flight', async () => {
+    const first = deferred<EventSource>();
+    const second = deferred<EventSource>();
+    const firstSource = new FakeEventSource();
+    const secondSource = new FakeEventSource();
+    const openEvents = vi.fn()
+      .mockImplementationOnce(() => first.promise)
+      .mockImplementationOnce(() => second.promise);
+    const store = createCodingConversationStore({
+      getSnapshot: vi.fn(),
+      openEvents,
+      submitPrompt: vi.fn(),
+      createId: ids(),
+    });
+
+    const firstConnect = store.getState().connectEvents();
+    store.getState().disconnectEvents();
+    const secondConnect = store.getState().connectEvents();
+    first.resolve(firstSource as unknown as EventSource);
+    await firstConnect;
+    const joinedSecondConnect = store.getState().connectEvents();
+
+    expect(openEvents).toHaveBeenCalledTimes(2);
+    expect(firstSource.close).toHaveBeenCalledOnce();
+    second.resolve(secondSource as unknown as EventSource);
+    await Promise.all([secondConnect, joinedSecondConnect]);
+    expect(openEvents).toHaveBeenCalledTimes(2);
+  });
+
+  it('reconciles an accepted optimistic node by clientRequestId without changing its UI id', async () => {
+    const pending = deferred<PromptAcceptance>();
+    const store = createCodingConversationStore({
+      getSnapshot: vi.fn(),
+      openEvents: vi.fn(),
+      submitPrompt: vi.fn(() => pending.promise),
+      createId: ids(),
+    });
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-a')));
+    store.getState().setDraft('conversation-a', 'Build it', [{
+      attachmentId: 'attachment-1',
+      mime: 'image/png',
+      previewUrl: 'blob:preview',
+    }]);
+
+    const submission = store.getState().submitPrompt({
+      conversationId: 'conversation-a',
+      mode: 'prompt',
+    });
+    const optimistic = selectCodingConversationSnapshot('conversation-a')(store.getState())?.nodes[0];
+    expect(optimistic).toMatchObject({ id: 'node-1', clientRequestId: 'request-1', status: 'optimistic' });
+    expect(store.getState().draftsByConversationId['conversation-a']).toMatchObject({
+      text: '',
+      attachments: [],
+    });
+
+    pending.resolve(acceptance('conversation-a', 'request-1'));
+    await submission;
+    expect(store.getState().requestsByConversationId['conversation-a']['request-1'].status)
+      .toBe('accepted');
+    store.getState().applyPatchEvent(patchEvent('conversation-a', 1, {
+      op: 'message.upsert',
+      node: {
+        kind: 'message',
+        id: 'durable-user-1',
+        sourceEntryId: 'entry-user-1',
+        clientRequestId: 'request-1',
+        role: 'user',
+        status: 'complete',
+        blocks: [{ kind: 'text', id: 'text-1', text: 'Build it', status: 'complete' }],
+      },
+    }));
+
+    expect(selectCodingConversationSnapshot('conversation-a')(store.getState())?.nodes[0])
+      .toMatchObject({ id: 'node-1', sourceEntryId: 'entry-user-1', status: 'complete' });
+    expect(store.getState().requestsByConversationId['conversation-a']).toEqual({});
+  });
+
+  it('restores draft attachments and marks the optimistic node on definite rejection', async () => {
+    const submitPrompt = vi.fn(async () => {
+      throw new AppError('RUNTIME', 'Model unavailable', undefined, {
+        backendCode: 'CODING_MODEL_UNAVAILABLE',
+      });
+    });
+    const store = createCodingConversationStore({
+      getSnapshot: vi.fn(),
+      openEvents: vi.fn(),
+      submitPrompt,
+      createId: ids(),
+    });
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-a')));
+    store.getState().setDraft('conversation-a', 'Try again', [{
+      attachmentId: 'attachment-1',
+      mime: 'image/png',
+      previewUrl: 'blob:preview',
+    }]);
+
+    await expect(store.getState().submitPrompt({
+      conversationId: 'conversation-a',
+      mode: 'prompt',
+    })).rejects.toThrow('Model unavailable');
+
+    expect(store.getState().draftsByConversationId['conversation-a']).toMatchObject({
+      text: 'Try again',
+      attachments: [{ attachmentId: 'attachment-1', mime: 'image/png', previewUrl: 'blob:preview' }],
+    });
+    expect(store.getState().requestsByConversationId['conversation-a']['request-1'])
+      .toMatchObject({ status: 'rejected', errorCode: 'CODING_MODEL_UNAVAILABLE' });
+    expect(selectCodingConversationSnapshot('conversation-a')(store.getState())?.nodes[0])
+      .toMatchObject({ id: 'node-1', status: 'error' });
+  });
+
+  it('keeps an uncertain optimistic request recoverable without replaying it on reconnect', async () => {
+    const source = new FakeEventSource();
+    const submitPrompt = vi.fn(async () => {
+      throw new AppError('NETWORK', 'Delivery is uncertain', undefined, {
+        backendCode: 'CODING_REQUEST_UNCERTAIN',
+      });
+    });
+    const store = createCodingConversationStore({
+      getSnapshot: vi.fn(async (conversationId: string) => snapshot(conversationId)),
+      openEvents: vi.fn(async () => source as unknown as EventSource),
+      submitPrompt,
+      createId: ids(),
+    });
+    await store.getState().selectConversation('conversation-a');
+    store.getState().setDraft('conversation-a', 'Do not replay');
+
+    await expect(store.getState().submitPrompt({
+      conversationId: 'conversation-a',
+      mode: 'prompt',
+    })).rejects.toThrow('Delivery is uncertain');
+    source.fail();
+    source.open();
+
+    expect(store.getState().draftsByConversationId['conversation-a'].text).toBe('Do not replay');
+    expect(store.getState().requestsByConversationId['conversation-a']['request-1'])
+      .toMatchObject({ status: 'uncertain', errorCode: 'CODING_REQUEST_UNCERTAIN' });
+    expect(selectCodingConversationSnapshot('conversation-a')(store.getState())?.nodes[0])
+      .toMatchObject({ id: 'node-1', status: 'optimistic' });
+    expect(submitPrompt).toHaveBeenCalledTimes(1);
+  });
+
+  it('does not rerender a selected timeline when a hidden Conversation streams', () => {
+    const store = createCodingConversationStore({
+      getSnapshot: vi.fn(),
+      openEvents: vi.fn(),
+      submitPrompt: vi.fn(),
+      createId: ids(),
+    });
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-a')));
+    store.getState().applySnapshotEvent(snapshotEvent(snapshot('conversation-b')));
+    const selectANodes = (state: ReturnType<typeof store.getState>) => (
+      selectCodingConversationSnapshot('conversation-a')(state)?.nodes ?? []
+    );
+    let renderCount = 0;
+    const { result } = renderHook(() => {
+      renderCount += 1;
+      return useStore(store, selectANodes);
+    });
+    const initialRenderCount = renderCount;
+    const aNodes = result.current;
+
+    act(() => {
+      store.getState().applyPatchEvent(patchEvent('conversation-b', 1, {
+        op: 'message.upsert',
+        node: {
+          kind: 'message',
+          id: 'assistant-b',
+          role: 'assistant',
+          status: 'streaming',
+          blocks: [{ kind: 'text', id: 'text-b', text: 'token', status: 'streaming' }],
+        },
+      }));
+    });
+    expect(renderCount).toBe(initialRenderCount);
+    expect(result.current).toBe(aNodes);
+    const streamingSummary = store.getState().summariesByConversationId['conversation-b'];
+    act(() => {
+      store.getState().applyPatchEvent(patchEvent('conversation-b', 2, {
+        op: 'message.block-delta',
+        messageId: 'assistant-b',
+        blockId: 'text-b',
+        delta: ' two',
+      }));
+    });
+    expect(store.getState().summariesByConversationId['conversation-b']).toBe(streamingSummary);
+    expect(renderCount).toBe(initialRenderCount);
+
+    act(() => {
+      store.getState().applyPatchEvent(patchEvent('conversation-a', 1, {
+        op: 'message.upsert',
+        node: {
+          kind: 'message',
+          id: 'assistant-a',
+          role: 'assistant',
+          status: 'streaming',
+          blocks: [{ kind: 'text', id: 'text-a', text: 'token', status: 'streaming' }],
+        },
+      }));
+    });
+    expect(renderCount).toBe(initialRenderCount + 1);
+    expect(result.current).not.toBe(aNodes);
+  });
+
+  it('keeps the Renderer surface vendor-neutral and both runtimes on the same reducer', async () => {
+    const files = [
+      '../../src/types/coding-conversation.ts',
+      '../../src/lib/coding-conversations.ts',
+      '../../src/stores/coding-conversations.ts',
+    ];
+    for (const relativePath of files) {
+      const source = await readFile(fileURLToPath(new URL(relativePath, import.meta.url)), 'utf8');
+      expect(source).not.toMatch(/opencode|(?:import|export)[\s\S]*?from\s+['"][^'"]*pi(?:-|\/)/i);
+      expect(source).not.toMatch(/\bPi[A-Z][A-Za-z]*/);
+    }
+
+    const [shared, main] = await Promise.all([
+      import('../../shared/coding-conversation-reducer'),
+      import('../../electron/coding-runtime/conversation-reducer'),
+    ]);
+    expect(main.createConversationReducerState).toBe(shared.createConversationReducerState);
+    expect(main.reduceConversationPatch).toBe(shared.reduceConversationPatch);
+  });
+});