diff --git a/docs/automation/cron-jobs.md b/docs/automation/cron-jobs.md
index e73a919c03b3..34c66af7c1c0 100644
--- a/docs/automation/cron-jobs.md
+++ b/docs/automation/cron-jobs.md
@@ -634,12 +634,12 @@ Query-string tokens are rejected.
     - Supplying both a concrete `channel` and `to` enables direct announce delivery.
     - Set `accountId` with `channel` and `to` to select a configured, enabled account on multi-account channels. Unknown, disabled, or invalid account IDs return `400` and schedule no run.
 
-    The HTTP response waits only for runner admission, not for the agent turn to finish. A `200` may take up to 15 seconds and means the run entered its agent runner. Pre-run failures return `{ ok: false, error, runId }` with:
+    The HTTP response waits only for canonical session/global placement admission, not for the agent turn to finish. A `200` may take up to 15 seconds and means the execution path acquired that admission; the run may still be preparing its model runtime. Pre-admission failures return `{ ok: false, error, runId }` with:
 
     - `400` when delivery coordinates or account selection are invalid; correct the request before retrying.
     - `409` when the target session changed or otherwise rejects new work; retry after resolving the session conflict.
-    - `502` when Gateway or cron preparation fails before runner entry.
-    - `503` when runner admission does not complete within 15 seconds. Timed-out queued work is canceled and does not start later.
+    - `502` when Gateway or cron preparation fails before placement admission.
+    - `503` when placement admission does not occur within 15 seconds. Timed-out queued work is canceled and does not start later.
 
   </Accordion>
   <Accordion title="Mapped hooks (POST /hooks/<name>)">
diff --git a/docs/gateway/configuration-reference.md b/docs/gateway/configuration-reference.md
index d38e0cac79ad..fe703be40975 100644
--- a/docs/gateway/configuration-reference.md
+++ b/docs/gateway/configuration-reference.md
@@ -1114,8 +1114,8 @@ Validation and safety notes:
   - Direct announce delivery requires both a concrete `channel` and `to`; supplying only one fails before the run is scheduled.
   - `accountId` selects a configured, enabled account for direct announce delivery and requires both `channel` and `to`; invalid selections return `400` before a run starts.
   - Omit both delivery fields for completion-only hooks, or set `deliver: false` to ignore supplied destination data.
-  - The request waits up to 15 seconds for runner admission, not run completion. `200` means the agent runner was entered.
-  - Pre-run failures return `{ ok: false, error, runId }`: `400` for invalid delivery coordinates or account selection, `409` for session admission conflicts, `502` for other preparation failures, and `503` when the 15-second admission deadline expires. Timed-out queued work is canceled and will not start later.
+  - The request waits up to 15 seconds for canonical session/global placement admission, not run completion. `200` means the execution path acquired that admission; the run may still be preparing its model runtime.
+  - Pre-admission failures return `{ ok: false, error, runId }`: `400` for invalid delivery coordinates or account selection, `409` for session admission conflicts, `502` for other preparation failures, and `503` when placement admission does not occur within 15 seconds. Timed-out queued work is canceled and will not start later.
 - `POST /hooks/<name>` → resolved via `hooks.mappings`
   - Template-rendered mapping `sessionKey` values are treated as externally supplied and also require `hooks.allowRequestSessionKey=true`.
   - Mapped `agent` actions use the same admission wait and `200`/`400`/`409`/`502`/`503` outcomes.
diff --git a/src/agents/embedded-agent-runner/run/lane-controller.queue-liveness.test.ts b/src/agents/embedded-agent-runner/run/lane-controller.queue-liveness.test.ts
index d27114b2d4d8..21653cdfdb8c 100644
--- a/src/agents/embedded-agent-runner/run/lane-controller.queue-liveness.test.ts
+++ b/src/agents/embedded-agent-runner/run/lane-controller.queue-liveness.test.ts
@@ -207,7 +207,8 @@ describe("queued embedded run context liveness", () => {
     const registeredAt = 1_000;
     const admissionAt = registeredAt + CONTEXT_TTL_MS + 1;
     const clock = vi.spyOn(Date, "now").mockReturnValue(registeredAt);
-    const { controller, params } = createRunController();
+    const onLaneWait = vi.fn();
+    const { controller, params } = createRunController({ onLaneWait });
     registerAgentRunContext(params.runId, {
       lifecycleGeneration: params.lifecycleGeneration,
       registeredAt,
@@ -235,6 +236,7 @@ describe("queued embedded run context liveness", () => {
 
     try {
       await placementEntered.promise;
+      expect(onLaneWait).not.toHaveBeenCalledWith(expect.objectContaining({ waiting: false }));
       expect(readAgentRunIndexVersion()).toBe(versionBeforeQueue);
       clock.mockReturnValue(admissionAt);
       expect(sweepStaleRunContexts()).toBe(0);
@@ -242,6 +244,11 @@ describe("queued embedded run context liveness", () => {
 
       placementAdmitted.resolve();
       await remoteStarted.promise;
+      expect(onLaneWait).toHaveBeenCalledExactlyOnceWith({
+        waitMs: 0,
+        queuedAhead: 0,
+        waiting: false,
+      });
       expect(getAgentRunContext(params.runId)?.lastActiveAt).toBe(admissionAt);
       expect(readAgentRunIndexVersion()).toBe(versionBeforeQueue + 1);
       expect(localTurn).not.toHaveBeenCalled();
diff --git a/src/agents/embedded-agent-runner/run/lane-controller.ts b/src/agents/embedded-agent-runner/run/lane-controller.ts
index 6ef6a403d1f2..406ade681cfc 100644
--- a/src/agents/embedded-agent-runner/run/lane-controller.ts
+++ b/src/agents/embedded-agent-runner/run/lane-controller.ts
@@ -126,7 +126,6 @@ export function createEmbeddedRunLaneController<TParams extends LaneParams>(opti
     };
     const taskWithCurrentLifecycle = async () => {
       let params = options.getParams();
-      params.onLaneWait?.({ waitMs: 0, queuedAhead: 0, waiting: false });
       params.replyOperation?.markGlobalLaneWaitEnded();
       throwIfAborted();
       let lifecycleGeneration = options.getLifecycleGeneration();
@@ -187,6 +186,8 @@ export function createEmbeddedRunLaneController<TParams extends LaneParams>(opti
               lifecycleGeneration,
               lastActiveAt: Date.now(),
             });
+            // Queue dequeue can still block on writer or placement admission.
+            params.onLaneWait?.({ waitMs: 0, queuedAhead: 0, waiting: false });
           },
         ),
       );
@@ -204,10 +205,6 @@ export function createEmbeddedRunLaneController<TParams extends LaneParams>(opti
   };
   const enqueueSession = <T>(task: () => Promise<T>, opts?: CommandQueueEnqueueOptions) => {
     const sessionOpts: CommandQueueEnqueueOptions = { ...opts, priority: sessionQueuePriority };
-    const taskWithLaneAdmission = () => {
-      options.getParams().onLaneWait?.({ waitMs: 0, queuedAhead: 0, waiting: false });
-      return task();
-    };
     const params = options.getParams();
     // Session admission, deferred maintenance, and global admission share one queue owner.
     releaseQueuedRunContext = retainQueuedAgentRunContext(
@@ -225,14 +222,10 @@ export function createEmbeddedRunLaneController<TParams extends LaneParams>(opti
     let queuedRun: Promise<T>;
     try {
       if (params.enqueue) {
-        queuedRun = params.enqueue(taskWithLaneAdmission, withRunLaneWait(sessionOpts));
+        queuedRun = params.enqueue(task, withRunLaneWait(sessionOpts));
       } else {
         noteLaneWaitIfBusy(options.sessionLane);
-        queuedRun = enqueueCommandInLane(
-          options.sessionLane,
-          taskWithLaneAdmission,
-          withRunLaneWait(sessionOpts),
-        );
+        queuedRun = enqueueCommandInLane(options.sessionLane, task, withRunLaneWait(sessionOpts));
       }
     } catch (error) {
       releaseQueuedContext("abandoned");
diff --git a/src/gateway/server.hooks-admission.test.ts b/src/gateway/server.hooks-admission.test.ts
index ef2076d43350..f178c082fe57 100644
--- a/src/gateway/server.hooks-admission.test.ts
+++ b/src/gateway/server.hooks-admission.test.ts
@@ -233,6 +233,47 @@ describe("gateway hook admission", () => {
     });
   });
 
+  test("admits an HTTP hook after placement while runtime preparation remains blocked", async () => {
+    testState.hooksConfig = { enabled: true, token: HOOK_TOKEN };
+    await withGatewayServer(async ({ port }) => {
+      const placementAdmissionPublished = createDeferred();
+      const runtimePreparation = createDeferred();
+      let runnerEntered = false;
+      let response: Response | undefined;
+      cronIsolatedRun.mockClear();
+      cronIsolatedRun.mockImplementationOnce(async (params: unknown) => {
+        const callbacks = params as {
+          onExecutionStarted?: () => void;
+          onLaneWait?: (info: { waiting: boolean }) => void;
+        };
+        callbacks.onLaneWait?.({ waiting: false });
+        placementAdmissionPublished.resolve();
+        await runtimePreparation.promise;
+        runnerEntered = true;
+        callbacks.onExecutionStarted?.();
+        return { status: "ok", summary: "done" };
+      });
+      const responsePromise = postHook(
+        port,
+        "/hooks/agent",
+        { message: "Dispatch" },
+        "placement-admission-before-runtime",
+      ).then((result) => {
+        response = result;
+        return result;
+      });
+
+      try {
+        await placementAdmissionPublished.promise;
+        await expect.poll(() => response?.status, { timeout: 1_000, interval: 10 }).toBe(200);
+        expect(runnerEntered).toBe(false);
+      } finally {
+        runtimePreparation.resolve();
+        await responsePromise;
+      }
+    });
+  });
+
   test("shares one pending persistent dispatch without losing its session target", async () => {
     testState.hooksConfig = {
       enabled: true,
diff --git a/src/gateway/server/hooks.ts b/src/gateway/server/hooks.ts
index e45906acd732..b22bc521f6c0 100644
--- a/src/gateway/server/hooks.ts
+++ b/src/gateway/server/hooks.ts
@@ -422,6 +422,10 @@ export function createGatewayHooksRequestHandler(params: {
     });
     const admissionTimeoutError = new Error(HOOK_AGENT_START_ADMISSION_TIMEOUT_ERROR);
     const startupAbortController = new AbortController();
+    const settleSuccessfulAdmission = () => {
+      startupAbortController.signal.throwIfAborted();
+      settleAdmission({ ok: true, runId });
+    };
     admissionTimer = setTimeout(() => {
       admissionTimedOut = true;
       startupAbortController.abort(admissionTimeoutError);
@@ -493,12 +497,12 @@ export function createGatewayHooksRequestHandler(params: {
                 },
               },
               abortSignal: startupAbortController.signal,
-              onExecutionStarted: () => {
-                // Existing runner-entry callbacks are the final owner-boundary fence:
-                // a deadline that wins this race prevents the runner call itself.
-                startupAbortController.signal.throwIfAborted();
-                settleAdmission({ ok: true, runId });
+              onLaneWait: (info) => {
+                if (info?.waiting === false) {
+                  settleSuccessfulAdmission();
+                }
               },
+              onExecutionStarted: settleSuccessfulAdmission,
             });
           const result = await runWithScheduledGatewayContext({
             ...(scheduledGatewayContextResolver