diff --git a/.project-docs/30-worklog/tasks/20260827-x01-preview-injection-9c4e2a71.md b/.project-docs/30-worklog/tasks/20260827-x01-preview-injection-9c4e2a71.md
new file mode 100644
index 0000000..6f54e07
--- /dev/null
+++ b/.project-docs/30-worklog/tasks/20260827-x01-preview-injection-9c4e2a71.md
@@ -0,0 +1,95 @@
+# Task: Remediate X-01 preview data injection target
+
+## Identity
+
+- Task ID: 20260827-x01-preview-injection-9c4e2a71
+- Mode: Feature
+- Branch: codex/20260827-x01-preview-injection-9c4e2a71-x01-preview-injection-9c4e2a71
+- Worktree: D:\Datas\OthersProjects\makelore-x01-preview-injection-9c4e2a71
+- Base commit: 2f346687b173137135dbd5259511d23505ff08dd
+- Owner: codex
+- Status: Ready for Integration
+
+## Scope
+
+- X-01 live-acceptance remediation on exact client coordinator HEAD
+  `2f346687b173137135dbd5259511d23505ff08dd`.
+- Fix the confirmed root `injectProjectData` preview failure in
+  `electron/agent-browser/module.ts` by passing the intended preview target
+  Origin explicitly into root preview-data installation.
+- Add the narrow Agent Browser regression test and this task-scoped record only.
+
+## Intent And Constraints
+
+- Follow Data Service P0 spec §10.4 and §14 groups 2 and 13, plus the X-01
+  remediation finding. Preserve explicit opt-in, exact-Origin capability
+  binding, child/sessionRef behavior, lifecycle cleanup, and ordinary browser
+  navigation without data injection.
+- The confirmed cause is that `open()` initializes `record.url` to the target,
+  prime navigation to `about:blank` mutates it, and root installation later
+  derives Origin from the mutated URL. The fix must carry the target URL
+  directly; it must not weaken Origin checks or add a second browser/preload.
+- Only this task worktree may be modified. The occupied coordinator worktree,
+  its untracked X-01 probe scripts, all other source files, and the prior ML-09
+  source worktree are read-only context.
+- Do not alter child/sessionRef installation semantics, route behavior, server
+  code, unrelated E2E selectors, or canonical project memory.
+
+## Planning Gate
+
+- Result: Passed on 2026-08-27.
+- Concurrent gate ran `check_project_docs.py`, then
+  `task_context.py start` against the occupied coordinator worktree with
+  `--base-ref 2f346687b173137135dbd5259511d23505ff08dd`; status JSON verified
+  this task ID, feature mode, absolute worktree/branch, and exact base.
+- Read the required MakeLore project-memory startup set, the coordinator task
+  record, Agent Browser architecture/data-flow seams, and the X-01 scope. The
+  coordinator owns the parent worktree and its live probes; this task owns only
+  the isolated module/test/record paths, with no unresolved semantic conflict.
+
+## Outcome
+
+- Passed the intended `targetUrl` explicitly to the root preview-data
+  installation call. Root session Origin now derives from that stable target
+  URL even when the prime `about:blank` navigation updates `record.url`;
+  child/sessionRef installation remains on its existing call path.
+- Added a narrow Agent Browser regression whose fake prime navigation emits
+  `did-navigate` for `about:blank`. Before the fix it observed `origin: "null"`;
+  after the fix it observes `http://127.0.0.1:4173`.
+
+## Plan
+
+1. Inspect the current root/child preview installation seam and add a failing
+   regression proving a prime `about:blank` navigation cannot change the Origin
+   used for root injection.
+2. Pass the intended target URL through root installation with the smallest
+   signature/call-site change; keep child/sessionRef handling unchanged.
+3. Run focused Agent Browser/preview tests, typecheck, scoped lint and diff/doc
+   gates, then commit once with a clean isolated worktree.
+
+## Verification
+
+- Red-first regression:
+  `pnpm exec vitest run tests/unit/agent-browser-core.test.ts -t "uses the
+  target Origin when the prime navigation reports about:blank" --maxWorkers=1`
+  failed as expected before the implementation (`received origin: "null"`).
+- Focused tests:
+  `pnpm exec vitest run tests/unit/agent-browser-core.test.ts
+  tests/unit/preview-data-session.test.ts --maxWorkers=1` — 2 files, 84 tests
+  passed.
+- `pnpm run typecheck` — passed.
+- `pnpm exec eslint electron/agent-browser/module.ts
+  tests/unit/agent-browser-core.test.ts` — passed.
+- `git diff --check` — passed.
+- No Electron E2E or live X-01 acceptance was run in this narrow remediation;
+  the coordinator must rerun live acceptance after integration.
+
+## Follow-ups
+
+- Parent coordinator should integrate the single commit and rerun X-01 with
+  the real PostgreSQL and signed-in MakeLore preview. Do not treat this
+  repository-local focused verification as live acceptance.
+
+## Promotion Candidates
+
+- None recorded.
diff --git a/electron/agent-browser/module.ts b/electron/agent-browser/module.ts
index f444e7e..270fb03 100644
--- a/electron/agent-browser/module.ts
+++ b/electron/agent-browser/module.ts
@@ -391,7 +391,7 @@ export class AgentBrowserModule {
           this.attachDebugger(record, false),
           OPEN_TIMEOUT_MS,
         );
-        if (injectProjectData) await this.installPreviewData(record);
+        if (injectProjectData) await this.installPreviewData(record, undefined, targetUrl);
       } catch (error) {
         await this.closeInternal(record);
         throw toFault(
@@ -796,6 +796,7 @@ export class AgentBrowserModule {
   private async installPreviewData(
     record: BrowserRecord,
     sessionRef?: string,
+    targetUrl?: string,
   ): Promise<void> {
     if (record !== this.record || record.view.webContents.isDestroyed()) {
       throw new AgentBrowserFault(
@@ -814,7 +815,7 @@ export class AgentBrowserModule {
     if (!sessionRef) {
       const openInput: PreviewDataSessionOpenInput = {
         projectPath: record.projectPath,
-        origin: new URL(record.url).origin,
+        origin: new URL(targetUrl ?? record.url).origin,
         browserGeneration: record.generation,
       };
       const session = await previewDataSession.open(openInput);
diff --git a/tests/unit/agent-browser-core.test.ts b/tests/unit/agent-browser-core.test.ts
index 0003119..d010f93 100644
--- a/tests/unit/agent-browser-core.test.ts
+++ b/tests/unit/agent-browser-core.test.ts
@@ -609,6 +609,33 @@ describe('AgentBrowserModule', () => {
     expect(externalGlobal.__MAKELORE_DATA__).toBeUndefined();
   });
 
+  it('uses the target Origin when the prime navigation reports about:blank', async () => {
+    const adapter = new FakeAdapter();
+    const preview = new FakePreviewDataSession();
+    adapter.onCreate = (view) => {
+      view.webContents.loadHandler = async (url) => {
+        view.webContents.emit('did-navigate', {}, url);
+      };
+      view.webContents.debugger.responders.set('Page.addScriptToEvaluateOnNewDocument', async () => ({
+        identifier: 'script-root',
+      }));
+    };
+    const module = new AgentBrowserModule(adapter, { previewDataSession: preview });
+
+    await module.open({
+      projectId: 'clock',
+      projectPath,
+      url: 'http://127.0.0.1:4173/',
+      injectProjectData: true,
+    });
+
+    expect(preview.opens).toEqual([{
+      projectPath,
+      origin: 'http://127.0.0.1:4173',
+      browserGeneration: 1,
+    }]);
+  });
+
   it('fails and tears down before target load when preview session setup fails', async () => {
     const adapter = new FakeAdapter();
     const preview = new FakePreviewDataSession();