diff --git a/src/agents/embedded-agent-runner/run/attempt-prompt-dispatch.test.ts b/src/agents/embedded-agent-runner/run/attempt-prompt-dispatch.test.ts
deleted file mode 100644
index 0086a7fec24e..000000000000
--- a/src/agents/embedded-agent-runner/run/attempt-prompt-dispatch.test.ts
+++ /dev/null
@@ -1,167 +0,0 @@
-import { beforeEach, describe, expect, it, vi } from "vitest";
-
-const hoisted = vi.hoisted(() => ({
-  observeEmbeddedAttemptPrompt: vi.fn(),
-  prepareEmbeddedAttemptPromptExecution: vi.fn(),
-  prepareEmbeddedAttemptPromptPreflight: vi.fn(),
-  submitEmbeddedAttemptPrompt: vi.fn(),
-}));
-
-vi.mock("./attempt-prompt-submit.js", () => ({
-  prepareEmbeddedAttemptPromptExecution: hoisted.prepareEmbeddedAttemptPromptExecution,
-  submitEmbeddedAttemptPrompt: hoisted.submitEmbeddedAttemptPrompt,
-}));
-vi.mock("./attempt-prompt-support.js", () => ({
-  observeEmbeddedAttemptPrompt: hoisted.observeEmbeddedAttemptPrompt,
-}));
-vi.mock("./attempt-prompt-preflight.js", () => ({
-  prepareEmbeddedAttemptPromptPreflight: hoisted.prepareEmbeddedAttemptPromptPreflight,
-}));
-import { dispatchEmbeddedAttemptPrompt } from "./attempt-prompt-dispatch.js";
-
-type DispatchInput = Parameters<typeof dispatchEmbeddedAttemptPrompt>[0];
-type PreflightMockInput = { state: DispatchInput["state"] };
-
-function createInput(overrides: Partial<DispatchInput> = {}): DispatchInput {
-  return {
-    attempt: { runId: "run-1", sessionId: "session-1" },
-    activeSession: { messages: [] },
-    promptContext: {
-      contextTokenBudget: 8_000,
-      effectivePrompt: "effective prompt",
-      hookMessagesForCurrentPrompt: [],
-      llmBoundaryPromptForPrecheck: "boundary prompt",
-      promptForModel: "model prompt",
-      promptForSession: "session prompt",
-      promptSubmission: { prompt: "submission prompt", runtimeOnly: false },
-      promptToolResultAggregateMaxChars: 8_000,
-      promptToolResultMaxChars: 4_000,
-      runtimeContextMessageForCurrentTurn: { role: "custom", content: "runtime" },
-      systemPromptForHook: "system prompt",
-    },
-    getCompactionReserveTokens: () => 1_000,
-    publishState: vi.fn(),
-    releaseLeasedSteering: vi.fn(),
-    state: {
-      contextBudgetStatus: undefined,
-      preflightRecovery: undefined,
-      promptError: null,
-      promptErrorSource: null,
-      skipPromptSubmission: false,
-    },
-    execution: {},
-    observation: {},
-    preflight: {},
-    submission: {},
-    ...overrides,
-  } as unknown as DispatchInput;
-}
-
-describe("dispatchEmbeddedAttemptPrompt", () => {
-  beforeEach(() => {
-    vi.clearAllMocks();
-    hoisted.prepareEmbeddedAttemptPromptExecution.mockResolvedValue({
-      images: [{ type: "image", data: "aW1hZ2U=", mimeType: "image/png" }],
-      imageFactIndexes: [null],
-      detectedRefs: [],
-      failedMediaCount: 0,
-      loadedCount: 1,
-      skippedCount: 0,
-    });
-    hoisted.observeEmbeddedAttemptPrompt.mockReturnValue({ skipPromptSubmission: false });
-    hoisted.prepareEmbeddedAttemptPromptPreflight.mockImplementation(
-      async (input: PreflightMockInput) => input.state,
-    );
-    hoisted.submitEmbeddedAttemptPrompt.mockResolvedValue(undefined);
-  });
-
-  it("runs image preparation, observability, preflight, and submission in order", async () => {
-    const order: string[] = [];
-    hoisted.prepareEmbeddedAttemptPromptExecution.mockImplementationOnce(async () => {
-      order.push("images");
-      return {
-        images: [{ type: "image", data: "aW1hZ2U=", mimeType: "image/png" }],
-        imageFactIndexes: [null],
-        detectedRefs: [],
-        failedMediaCount: 0,
-        loadedCount: 1,
-        skippedCount: 0,
-      };
-    });
-    hoisted.observeEmbeddedAttemptPrompt.mockImplementationOnce(() => {
-      order.push("observe");
-      return { skipPromptSubmission: false };
-    });
-    hoisted.prepareEmbeddedAttemptPromptPreflight.mockImplementationOnce(
-      async (input: PreflightMockInput) => {
-        order.push("preflight");
-        return input.state;
-      },
-    );
-    hoisted.submitEmbeddedAttemptPrompt.mockImplementationOnce(async () => {
-      order.push("submit");
-    });
-    const publishState = vi.fn(() => {
-      order.push("publish");
-    });
-    const input = createInput({ publishState });
-
-    await expect(dispatchEmbeddedAttemptPrompt(input)).resolves.toEqual(input.state);
-
-    expect(order).toEqual(["images", "observe", "publish", "preflight", "publish", "submit"]);
-    expect(hoisted.prepareEmbeddedAttemptPromptExecution).toHaveBeenCalledWith(
-      expect.objectContaining({ prompt: "submission prompt", skipPromptSubmission: false }),
-    );
-    expect(hoisted.observeEmbeddedAttemptPrompt).toHaveBeenCalledWith(
-      expect.objectContaining({ imageCount: 1, reserveTokens: 1_000 }),
-    );
-    expect(hoisted.submitEmbeddedAttemptPrompt).toHaveBeenCalledWith(
-      expect.objectContaining({
-        images: [expect.objectContaining({ type: "image" })],
-        modelPrompt: "model prompt",
-        runtimeContextMessage: expect.objectContaining({ content: "runtime" }),
-        transcriptPrompt: "session prompt",
-      }),
-    );
-  });
-
-  it("releases steering when preflight skips provider submission", async () => {
-    const promptError = new Error("preflight rejected");
-    const releaseLeasedSteering = vi.fn();
-    hoisted.observeEmbeddedAttemptPrompt.mockReturnValueOnce({ skipPromptSubmission: true });
-    hoisted.prepareEmbeddedAttemptPromptPreflight.mockImplementationOnce(
-      async (input: PreflightMockInput) => ({
-        ...input.state,
-        promptError,
-        promptErrorSource: "precheck",
-      }),
-    );
-
-    const result = await dispatchEmbeddedAttemptPrompt(createInput({ releaseLeasedSteering }));
-
-    expect(result.promptError).toBe(promptError);
-    expect(releaseLeasedSteering).toHaveBeenCalledWith(promptError);
-    expect(hoisted.submitEmbeddedAttemptPrompt).not.toHaveBeenCalled();
-  });
-
-  it("publishes preflight state before a submission failure", async () => {
-    const promptError = new Error("admission warning");
-    const submitError = new Error("provider failed");
-    const admittedState = {
-      contextBudgetStatus: undefined,
-      preflightRecovery: undefined,
-      promptError,
-      promptErrorSource: "precheck" as const,
-      skipPromptSubmission: false,
-    };
-    const publishState = vi.fn();
-    hoisted.prepareEmbeddedAttemptPromptPreflight.mockResolvedValueOnce(admittedState);
-    hoisted.submitEmbeddedAttemptPrompt.mockRejectedValueOnce(submitError);
-
-    await expect(dispatchEmbeddedAttemptPrompt(createInput({ publishState }))).rejects.toBe(
-      submitError,
-    );
-
-    expect(publishState).toHaveBeenLastCalledWith(admittedState);
-  });
-});
diff --git a/src/agents/embedded-agent-runner/run/attempt-prompt-dispatch.ts b/src/agents/embedded-agent-runner/run/attempt-prompt-dispatch.ts
deleted file mode 100644
index b67c68db6729..000000000000
--- a/src/agents/embedded-agent-runner/run/attempt-prompt-dispatch.ts
+++ /dev/null
@@ -1,138 +0,0 @@
-/** Runs prompt-local image preparation, observability, preflight, and provider dispatch. */
-import type { prepareEmbeddedAttemptPromptContext } from "./attempt-prompt-build.js";
-import { prepareEmbeddedAttemptPromptPreflight } from "./attempt-prompt-preflight.js";
-import {
-  prepareEmbeddedAttemptPromptExecution,
-  submitEmbeddedAttemptPrompt,
-} from "./attempt-prompt-submit.js";
-import { observeEmbeddedAttemptPrompt } from "./attempt-prompt-support.js";
-import type { EmbeddedRunAttemptParams } from "./types.js";
-
-type PromptContext = ReturnType<typeof prepareEmbeddedAttemptPromptContext>;
-type PromptExecutionInput = Parameters<typeof prepareEmbeddedAttemptPromptExecution>[0];
-type PromptObservationInput = Parameters<typeof observeEmbeddedAttemptPrompt>[0];
-type PromptPreflightInput = Parameters<typeof prepareEmbeddedAttemptPromptPreflight>[0];
-type PromptSubmissionInput = Parameters<typeof submitEmbeddedAttemptPrompt>[0];
-type PromptDispatchState = PromptPreflightInput["state"];
-
-export async function dispatchEmbeddedAttemptPrompt(input: {
-  attempt: EmbeddedRunAttemptParams;
-  activeContextEngine?: PromptPreflightInput["activeContextEngine"];
-  activeSession: PromptSubmissionInput["activeSession"];
-  promptContext: PromptContext;
-  getCompactionReserveTokens: () => number;
-  publishState: (state: PromptDispatchState) => void;
-  releaseLeasedSteering: (error?: unknown) => void;
-  state: PromptDispatchState;
-  execution: Omit<PromptExecutionInput, "attempt" | "prompt" | "session" | "skipPromptSubmission">;
-  observation: Omit<
-    PromptObservationInput,
-    | "attempt"
-    | "contextTokenBudget"
-    | "effectivePrompt"
-    | "hookMessagesForCurrentPrompt"
-    | "imageCount"
-    | "llmBoundaryPromptForPrecheck"
-    | "promptForModel"
-    | "promptSubmissionRuntimeOnly"
-    | "reserveTokens"
-    | "sessionMessages"
-    | "skipPromptSubmission"
-    | "systemPromptForHook"
-  >;
-  preflight: Omit<
-    PromptPreflightInput,
-    | "attempt"
-    | "activeContextEngine"
-    | "contextTokenBudget"
-    | "hookMessagesForCurrentPrompt"
-    | "promptForPrecheck"
-    | "reserveTokens"
-    | "sessionMessageCount"
-    | "state"
-    | "systemPrompt"
-    | "toolResultMaxChars"
-  >;
-  submission: Omit<
-    PromptSubmissionInput,
-    | "attempt"
-    | "activeSession"
-    | "contextTokenBudget"
-    | "images"
-    | "modelPrompt"
-    | "runtimeContextMessage"
-    | "runtimeOnly"
-    | "systemPrompt"
-    | "toolResultAggregateMaxChars"
-    | "toolResultMaxChars"
-    | "transcriptPrompt"
-  >;
-}): Promise<PromptDispatchState> {
-  const { activeSession, attempt, promptContext } = input;
-  const imageResult = await prepareEmbeddedAttemptPromptExecution({
-    ...input.execution,
-    attempt,
-    prompt: promptContext.promptSubmission.prompt,
-    skipPromptSubmission: input.state.skipPromptSubmission,
-  });
-
-  const reserveTokens = input.getCompactionReserveTokens();
-  let state: PromptDispatchState = {
-    ...input.state,
-    skipPromptSubmission: observeEmbeddedAttemptPrompt({
-      ...input.observation,
-      attempt,
-      contextTokenBudget: promptContext.contextTokenBudget,
-      effectivePrompt: promptContext.effectivePrompt,
-      hookMessagesForCurrentPrompt: promptContext.hookMessagesForCurrentPrompt,
-      imageCount: imageResult.images.length,
-      llmBoundaryPromptForPrecheck: promptContext.llmBoundaryPromptForPrecheck,
-      promptForModel: promptContext.promptForModel,
-      promptSubmissionRuntimeOnly: promptContext.promptSubmission.runtimeOnly,
-      reserveTokens,
-      sessionMessages: activeSession.messages,
-      skipPromptSubmission: input.state.skipPromptSubmission,
-      systemPromptForHook: promptContext.systemPromptForHook,
-    }).skipPromptSubmission,
-  };
-  // Publish each admission transition before the next fallible phase so outer cleanup sees it.
-  input.publishState(state);
-
-  state = await prepareEmbeddedAttemptPromptPreflight({
-    ...input.preflight,
-    attempt,
-    ...(input.activeContextEngine ? { activeContextEngine: input.activeContextEngine } : {}),
-    contextTokenBudget: promptContext.contextTokenBudget,
-    hookMessagesForCurrentPrompt: promptContext.hookMessagesForCurrentPrompt,
-    promptForPrecheck: promptContext.llmBoundaryPromptForPrecheck,
-    reserveTokens,
-    sessionMessageCount: activeSession.messages.length,
-    state,
-    systemPrompt: promptContext.systemPromptForHook,
-    toolResultMaxChars: promptContext.promptToolResultMaxChars,
-  });
-  input.publishState(state);
-
-  if (!state.skipPromptSubmission) {
-    await submitEmbeddedAttemptPrompt({
-      ...input.submission,
-      attempt,
-      activeSession,
-      contextTokenBudget: promptContext.contextTokenBudget,
-      images: imageResult.images,
-      modelPrompt: promptContext.promptForModel,
-      ...(promptContext.runtimeContextMessageForCurrentTurn
-        ? { runtimeContextMessage: promptContext.runtimeContextMessageForCurrentTurn }
-        : {}),
-      runtimeOnly: promptContext.promptSubmission.runtimeOnly === true,
-      systemPrompt: promptContext.systemPromptForHook,
-      toolResultAggregateMaxChars: promptContext.promptToolResultAggregateMaxChars,
-      toolResultMaxChars: promptContext.promptToolResultMaxChars,
-      transcriptPrompt: promptContext.promptForSession,
-    });
-  } else {
-    input.releaseLeasedSteering(state.promptError ?? "prompt submission skipped");
-  }
-
-  return state;
-}
diff --git a/src/agents/embedded-agent-runner/run/attempt-prompt-phase.test.ts b/src/agents/embedded-agent-runner/run/attempt-prompt-phase.test.ts
index 20b98f175a5c..5a13b3314a8b 100644
--- a/src/agents/embedded-agent-runner/run/attempt-prompt-phase.test.ts
+++ b/src/agents/embedded-agent-runner/run/attempt-prompt-phase.test.ts
@@ -1,16 +1,20 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
 const mocks = vi.hoisted(() => ({
+  applyPromptToolsAllow: vi.fn(),
   beforeAgentRun: vi.fn(),
-  dispatchPrompt: vi.fn(),
   handlePromptError: vi.fn(),
   handleMidTurnPrecheck: vi.fn(),
+  observePrompt: vi.fn(),
   prepareGooglePromptCache: vi.fn(),
   preparePromptAssembly: vi.fn(),
   preparePromptContext: vi.fn(),
+  preparePromptExecution: vi.fn(),
+  preparePromptPreflight: vi.fn(),
   releasePendingSteering: vi.fn(),
   removeTrailingPrecheckError: vi.fn(),
   resolveApiKey: vi.fn(),
+  submitPrompt: vi.fn(),
   debug: vi.fn(),
   warn: vi.fn(),
 }));
@@ -36,35 +40,34 @@ vi.mock("./attempt-prompt-build.js", () => ({
   prepareEmbeddedAttemptPromptAssembly: mocks.preparePromptAssembly,
   prepareEmbeddedAttemptPromptContext: mocks.preparePromptContext,
 }));
-vi.mock("./attempt-prompt-dispatch.js", () => ({
-  dispatchEmbeddedAttemptPrompt: mocks.dispatchPrompt,
-}));
 vi.mock("./attempt-prompt-submit.js", () => ({
   handleEmbeddedAttemptPromptError: mocks.handlePromptError,
+  prepareEmbeddedAttemptPromptExecution: mocks.preparePromptExecution,
+  submitEmbeddedAttemptPrompt: mocks.submitPrompt,
 }));
 vi.mock("./attempt-prompt-preflight.js", () => ({
   handleEmbeddedAttemptMidTurnPrecheck: mocks.handleMidTurnPrecheck,
+  prepareEmbeddedAttemptPromptPreflight: mocks.preparePromptPreflight,
+}));
+vi.mock("./attempt-prompt-support.js", () => ({
+  applyPromptBuildToolsAllow: mocks.applyPromptToolsAllow,
+  observeEmbeddedAttemptPrompt: mocks.observePrompt,
 }));
 vi.mock("./attempt-transcript-helpers.js", () => ({
   removeTrailingMidTurnPrecheckAssistantError: mocks.removeTrailingPrecheckError,
 }));
 
 import { runEmbeddedAttemptPromptPhase } from "./attempt-prompt-phase.js";
+import type { prepareEmbeddedAttemptPromptPreflight } from "./attempt-prompt-preflight.js";
+import type { submitEmbeddedAttemptPrompt } from "./attempt-prompt-submit.js";
 
 type PromptPhaseInput = Parameters<typeof runEmbeddedAttemptPromptPhase>[0];
 type PromptPhaseState = ReturnType<PromptPhaseInput["lifecycle"]["readState"]>;
 type AssemblyCall = {
   setLeasedSteering: (lease: { leaseId: string; runIds: string[] }) => void;
 };
-type DispatchCall = {
-  getCompactionReserveTokens: () => number;
-  publishState: (state: PromptPhaseState & { skipPromptSubmission: boolean }) => void;
-  state: PromptPhaseState & { skipPromptSubmission: boolean };
-  submission: {
-    onFinalPromptText: (prompt: string) => void;
-    onSteeringAcknowledged: () => void;
-  };
-};
+type PromptPreflightCall = Parameters<typeof prepareEmbeddedAttemptPromptPreflight>[0];
+type PromptSubmissionCall = Parameters<typeof submitEmbeddedAttemptPrompt>[0];
 type PromptErrorCall = {
   error: unknown;
   markYieldAborted: () => void;
@@ -128,7 +131,7 @@ function createFixture() {
       promptSubmission: { prompt: "hello", runtimeOnly: false },
       promptToolResultAggregateMaxChars: 2_000,
       promptToolResultMaxChars: 1_000,
-      runtimeContextMessageForCurrentTurn: undefined,
+      runtimeContextMessageForCurrentTurn: { role: "custom", content: "runtime" },
       systemPromptForHook: "system",
     };
   });
@@ -141,15 +144,31 @@ function createFixture() {
     order.push("google-cache");
     return undefined;
   });
-  mocks.dispatchPrompt.mockImplementation(async (input: DispatchCall) => {
-    order.push("dispatch");
-    expect(input.getCompactionReserveTokens()).toBe(77);
-    input.submission.onFinalPromptText("hello");
-    input.submission.onSteeringAcknowledged();
-    const nextState = { ...input.state, skipPromptSubmission: false };
-    input.publishState(nextState);
-    return nextState;
+  mocks.preparePromptExecution.mockImplementation(async () => {
+    order.push("images");
+    return {
+      images: [{ type: "image", data: "aW1hZ2U=", mimeType: "image/png" }],
+      imageFactIndexes: [null],
+      detectedRefs: [],
+      failedMediaCount: 0,
+      loadedCount: 1,
+      skippedCount: 0,
+    };
   });
+  mocks.observePrompt.mockImplementation(() => {
+    order.push("observe");
+    return { skipPromptSubmission: false };
+  });
+  mocks.preparePromptPreflight.mockImplementation(async (preflightInput: PromptPreflightCall) => {
+    order.push("preflight");
+    return preflightInput.state;
+  });
+  mocks.submitPrompt.mockImplementation(async (submissionInput: PromptSubmissionCall) => {
+    order.push("submit");
+    submissionInput.onFinalPromptText("hello");
+    submissionInput.onSteeringAcknowledged();
+  });
+  mocks.handlePromptError.mockResolvedValue({});
 
   const activeSession = {
     messages: [],
@@ -231,7 +250,10 @@ function createFixture() {
     },
     lifecycle: {
       readState: () => state,
-      writeState: (nextState: PromptPhaseState) => Object.assign(state, nextState),
+      writeState: (nextState: PromptPhaseState) => {
+        order.push("publish");
+        Object.assign(state, nextState);
+      },
       getPrePromptMessageCount: () => prePromptMessageCount,
       setPrePromptMessageCount,
       setCurrentUserTimestampOverride: vi.fn(),
@@ -274,19 +296,39 @@ describe("runEmbeddedAttemptPromptPhase", () => {
       "context",
       "before-agent-run",
       "google-cache",
-      "dispatch",
+      "images",
+      "observe",
+      "publish",
+      "preflight",
+      "publish",
+      "submit",
+      "publish",
       "stop-steering",
     ]);
     expect(fixture.setPrePromptMessageCount).toHaveBeenCalledWith(2);
     expect(fixture.setPromptCacheChangesForTurn).toHaveBeenCalledWith([]);
     expect(fixture.setFinalPromptText).toHaveBeenCalledWith("hello");
-    expect(mocks.dispatchPrompt).toHaveBeenCalledWith(
+    expect(mocks.preparePromptExecution).toHaveBeenCalledWith(
       expect.objectContaining({
-        observation: expect.objectContaining({ transcriptLeafId: "leaf-1" }),
-        submission: expect.objectContaining({
-          leasedSteering: { leaseId: "lease-1", runIds: ["run-1"] },
-          transcriptLeafId: "leaf-1",
-        }),
+        prompt: "hello",
+        skipPromptSubmission: false,
+      }),
+    );
+    expect(mocks.observePrompt).toHaveBeenCalledWith(
+      expect.objectContaining({
+        imageCount: 1,
+        reserveTokens: 77,
+        transcriptLeafId: "leaf-1",
+      }),
+    );
+    expect(mocks.submitPrompt).toHaveBeenCalledWith(
+      expect.objectContaining({
+        images: [expect.objectContaining({ type: "image" })],
+        leasedSteering: { leaseId: "lease-1", runIds: ["run-1"] },
+        modelPrompt: "hello",
+        runtimeContextMessage: expect.objectContaining({ content: "runtime" }),
+        transcriptLeafId: "leaf-1",
+        transcriptPrompt: "hello",
       }),
     );
     expect(mocks.releasePendingSteering).not.toHaveBeenCalled();
@@ -303,7 +345,13 @@ describe("runEmbeddedAttemptPromptPhase", () => {
       "assembly",
       "context",
       "google-cache",
-      "dispatch",
+      "images",
+      "observe",
+      "publish",
+      "preflight",
+      "publish",
+      "submit",
+      "publish",
       "stop-steering",
     ]);
   });
@@ -318,23 +366,18 @@ describe("runEmbeddedAttemptPromptPhase", () => {
 
     await runEmbeddedAttemptPromptPhase(fixture.input);
 
-    expect(mocks.dispatchPrompt).toHaveBeenCalledWith(
-      expect.objectContaining({
-        state: expect.objectContaining({
-          skipPromptSubmission: false,
-          promptError: null,
-          promptErrorSource: null,
-        }),
-      }),
+    expect(mocks.preparePromptExecution).toHaveBeenCalledWith(
+      expect.objectContaining({ skipPromptSubmission: false }),
     );
+    expect(mocks.submitPrompt).toHaveBeenCalledOnce();
   });
 
   it("reads yield state after submission fails and publishes abort state before recovery", async () => {
     const fixture = createFixture();
     const submissionError = new Error("submission failed");
     const yieldAbortSettled = Promise.resolve();
-    mocks.dispatchPrompt.mockImplementation(async () => {
-      fixture.order.push("dispatch");
+    mocks.submitPrompt.mockImplementation(async () => {
+      fixture.order.push("submit");
       fixture.yieldState.yieldDetected = true;
       fixture.yieldState.yieldAbortSettled = yieldAbortSettled;
       fixture.yieldState.yieldMessage = "yield context";
@@ -355,7 +398,7 @@ describe("runEmbeddedAttemptPromptPhase", () => {
     });
 
     expect(fixture.order.slice(-4)).toEqual([
-      "dispatch",
+      "submit",
       "prompt-error",
       "yield-aborted",
       "stop-steering",
@@ -365,4 +408,71 @@ describe("runEmbeddedAttemptPromptPhase", () => {
       expect.objectContaining({ leaseId: "lease-1", runIds: ["run-1"] }),
     );
   });
+
+  it("releases steering when preflight skips provider submission", async () => {
+    const fixture = createFixture();
+    const promptError = new Error("preflight rejected");
+    mocks.observePrompt.mockImplementationOnce(() => {
+      fixture.order.push("observe");
+      return { skipPromptSubmission: true };
+    });
+    mocks.preparePromptPreflight.mockImplementationOnce(
+      async (preflightInput: PromptPreflightCall) => {
+        fixture.order.push("preflight");
+        return {
+          ...preflightInput.state,
+          promptError,
+          promptErrorSource: "precheck",
+        };
+      },
+    );
+
+    await runEmbeddedAttemptPromptPhase(fixture.input);
+
+    expect(fixture.state.promptError).toBe(promptError);
+    expect(mocks.releasePendingSteering).toHaveBeenCalledWith(
+      expect.objectContaining({
+        error: "preflight rejected",
+        leaseId: "lease-1",
+        runIds: ["run-1"],
+      }),
+    );
+    expect(mocks.submitPrompt).not.toHaveBeenCalled();
+  });
+
+  it("publishes preflight state before a submission failure", async () => {
+    const fixture = createFixture();
+    const promptError = new Error("admission warning");
+    const submitError = new Error("provider failed");
+    mocks.preparePromptPreflight.mockImplementationOnce(
+      async (preflightInput: PromptPreflightCall) => {
+        fixture.order.push("preflight");
+        return {
+          ...preflightInput.state,
+          promptError,
+          promptErrorSource: "precheck",
+        };
+      },
+    );
+    mocks.submitPrompt.mockImplementationOnce(async () => {
+      fixture.order.push("submit");
+      expect(fixture.state.promptError).toBe(promptError);
+      throw submitError;
+    });
+    mocks.handlePromptError.mockImplementationOnce(async (errorInput: PromptErrorCall) => {
+      fixture.order.push("prompt-error");
+      expect(errorInput.error).toBe(submitError);
+      return {};
+    });
+
+    await runEmbeddedAttemptPromptPhase(fixture.input);
+
+    expect(fixture.order.slice(-5)).toEqual([
+      "preflight",
+      "publish",
+      "submit",
+      "prompt-error",
+      "stop-steering",
+    ]);
+  });
 });
diff --git a/src/agents/embedded-agent-runner/run/attempt-prompt-phase.ts b/src/agents/embedded-agent-runner/run/attempt-prompt-phase.ts
index 246fec1ed22f..720b3632d170 100644
--- a/src/agents/embedded-agent-runner/run/attempt-prompt-phase.ts
+++ b/src/agents/embedded-agent-runner/run/attempt-prompt-phase.ts
@@ -13,10 +13,19 @@ import {
   prepareEmbeddedAttemptPromptAssembly,
   prepareEmbeddedAttemptPromptContext,
 } from "./attempt-prompt-build.js";
-import { dispatchEmbeddedAttemptPrompt } from "./attempt-prompt-dispatch.js";
-import { handleEmbeddedAttemptMidTurnPrecheck } from "./attempt-prompt-preflight.js";
-import { handleEmbeddedAttemptPromptError } from "./attempt-prompt-submit.js";
-import { applyPromptBuildToolsAllow } from "./attempt-prompt-support.js";
+import {
+  handleEmbeddedAttemptMidTurnPrecheck,
+  prepareEmbeddedAttemptPromptPreflight,
+} from "./attempt-prompt-preflight.js";
+import {
+  handleEmbeddedAttemptPromptError,
+  prepareEmbeddedAttemptPromptExecution,
+  submitEmbeddedAttemptPrompt,
+} from "./attempt-prompt-submit.js";
+import {
+  applyPromptBuildToolsAllow,
+  observeEmbeddedAttemptPrompt,
+} from "./attempt-prompt-support.js";
 import { removeTrailingMidTurnPrecheckAssistantError } from "./attempt-transcript-helpers.js";
 import type { MidTurnPrecheckRequest } from "./midturn-precheck.js";
 
@@ -24,12 +33,15 @@ type PromptAssemblyInput = Parameters<typeof prepareEmbeddedAttemptPromptAssembl
 type PromptAssemblyResult = Awaited<ReturnType<typeof prepareEmbeddedAttemptPromptAssembly>>;
 type PromptContextInput = Parameters<typeof prepareEmbeddedAttemptPromptContext>[0];
 type PromptContextResult = ReturnType<typeof prepareEmbeddedAttemptPromptContext>;
-type PromptDispatchInput = Parameters<typeof dispatchEmbeddedAttemptPrompt>[0];
 type PromptErrorInput = Parameters<typeof handleEmbeddedAttemptPromptError>[0];
+type PromptExecutionInput = Parameters<typeof prepareEmbeddedAttemptPromptExecution>[0];
+type PromptObservationInput = Parameters<typeof observeEmbeddedAttemptPrompt>[0];
+type PromptPreflightInput = Parameters<typeof prepareEmbeddedAttemptPromptPreflight>[0];
+type PromptSubmissionInput = Parameters<typeof submitEmbeddedAttemptPrompt>[0];
 type BeforeAgentRunOutcome = NonNullable<
   Awaited<ReturnType<typeof runEmbeddedAttemptBeforeAgentRun>>
 >;
-type PromptPhaseState = Omit<PromptDispatchInput["state"], "skipPromptSubmission">;
+type PromptPhaseState = Omit<PromptPreflightInput["state"], "skipPromptSubmission">;
 
 type PromptAssemblyPhaseInput = Omit<
   PromptAssemblyInput,
@@ -43,14 +55,44 @@ type PromptContextPhaseInput = Omit<
   PromptContextInput,
   "attempt" | "messages" | "prompt" | "replaceSessionMessages"
 >;
-type PromptExecutionPhaseInput = PromptDispatchInput["execution"];
-type PromptObservationPhaseInput = Omit<PromptDispatchInput["observation"], "transcriptLeafId">;
+type PromptExecutionPhaseInput = Omit<
+  PromptExecutionInput,
+  "attempt" | "prompt" | "skipPromptSubmission"
+>;
+type PromptObservationPhaseInput = Omit<
+  PromptObservationInput,
+  | "attempt"
+  | "contextTokenBudget"
+  | "effectivePrompt"
+  | "hookMessagesForCurrentPrompt"
+  | "imageCount"
+  | "llmBoundaryPromptForPrecheck"
+  | "promptForModel"
+  | "promptSubmissionRuntimeOnly"
+  | "reserveTokens"
+  | "sessionMessages"
+  | "skipPromptSubmission"
+  | "systemPromptForHook"
+  | "transcriptLeafId"
+>;
 type PromptToolSurface = ReturnType<typeof applyPromptBuildToolsAllow>;
-type PromptPreflightPhaseInput = PromptDispatchInput["preflight"] & {
-  activeContextEngine?: PromptDispatchInput["activeContextEngine"];
+type PromptPreflightPhaseInput = Omit<
+  PromptPreflightInput,
+  | "attempt"
+  | "activeContextEngine"
+  | "contextTokenBudget"
+  | "hookMessagesForCurrentPrompt"
+  | "promptForPrecheck"
+  | "reserveTokens"
+  | "sessionMessageCount"
+  | "state"
+  | "systemPrompt"
+  | "toolResultMaxChars"
+> & {
+  activeContextEngine?: PromptPreflightInput["activeContextEngine"];
 };
 type PromptSubmissionPhaseInput = Pick<
-  PromptDispatchInput["submission"],
+  PromptSubmissionInput,
   | "promptActiveSession"
   | "sessionPromptState"
   | "toolResultPromptProjectionState"
@@ -113,7 +155,7 @@ export async function runEmbeddedAttemptPromptPhase(input: {
   const patchState = (patch: Partial<PromptPhaseState>) => {
     input.lifecycle.writeState({ ...input.lifecycle.readState(), ...patch });
   };
-  const publishDispatchState = (state: PromptDispatchInput["state"]) => {
+  const publishDispatchState = (state: PromptPreflightInput["state"]) => {
     const { skipPromptSubmission: nextSkipPromptSubmission, ...phaseState } = state;
     skipPromptSubmission = nextSkipPromptSubmission;
     input.lifecycle.writeState(phaseState);
@@ -264,21 +306,17 @@ export async function runEmbeddedAttemptPromptPhase(input: {
       }
     }
 
-    const { activeContextEngine, ...preflight } = input.preflight;
-    const dispatchState = await dispatchEmbeddedAttemptPrompt({
+    const imageResult = await prepareEmbeddedAttemptPromptExecution({
+      ...input.execution,
       attempt,
-      ...(activeContextEngine ? { activeContextEngine } : {}),
-      activeSession,
-      promptContext,
-      getCompactionReserveTokens: input.getCompactionReserveTokens,
-      publishState: publishDispatchState,
-      releaseLeasedSteering,
-      state: {
-        ...input.lifecycle.readState(),
-        skipPromptSubmission,
-      },
-      execution: input.execution,
-      observation: {
+      prompt: promptContext.promptSubmission.prompt,
+      skipPromptSubmission,
+    });
+
+    const reserveTokens = input.getCompactionReserveTokens();
+    let state: PromptPreflightInput["state"] = {
+      ...input.lifecycle.readState(),
+      skipPromptSubmission: observeEmbeddedAttemptPrompt({
         ...input.observation,
         ...(promptToolSurface
           ? {
@@ -287,22 +325,69 @@ export async function runEmbeddedAttemptPromptPhase(input: {
               uncompactedEffectiveTools: promptToolSurface.uncompactedEffectiveTools,
             }
           : {}),
+        attempt,
+        contextTokenBudget: promptContext.contextTokenBudget,
+        effectivePrompt: promptContext.effectivePrompt,
+        hookMessagesForCurrentPrompt: promptContext.hookMessagesForCurrentPrompt,
+        imageCount: imageResult.images.length,
+        llmBoundaryPromptForPrecheck: promptContext.llmBoundaryPromptForPrecheck,
+        promptForModel: promptContext.promptForModel,
+        promptSubmissionRuntimeOnly: promptContext.promptSubmission.runtimeOnly,
+        reserveTokens,
+        sessionMessages: activeSession.messages,
+        skipPromptSubmission,
+        systemPromptForHook: promptContext.systemPromptForHook,
         transcriptLeafId,
-      },
-      preflight,
-      submission: {
+      }).skipPromptSubmission,
+    };
+    // Publish each admission transition before the next fallible phase so outer cleanup sees it.
+    publishDispatchState(state);
+
+    const { activeContextEngine, ...preflight } = input.preflight;
+    state = await prepareEmbeddedAttemptPromptPreflight({
+      ...preflight,
+      attempt,
+      ...(activeContextEngine ? { activeContextEngine } : {}),
+      contextTokenBudget: promptContext.contextTokenBudget,
+      hookMessagesForCurrentPrompt: promptContext.hookMessagesForCurrentPrompt,
+      promptForPrecheck: promptContext.llmBoundaryPromptForPrecheck,
+      reserveTokens,
+      sessionMessageCount: activeSession.messages.length,
+      state,
+      systemPrompt: promptContext.systemPromptForHook,
+      toolResultMaxChars: promptContext.promptToolResultMaxChars,
+    });
+    publishDispatchState(state);
+
+    if (!state.skipPromptSubmission) {
+      await submitEmbeddedAttemptPrompt({
         ...(promptBuildAppendContext ? { appendContext: promptBuildAppendContext } : {}),
+        attempt,
+        activeSession,
+        contextTokenBudget: promptContext.contextTokenBudget,
+        images: imageResult.images,
         ...(leasedSteering ? { leasedSteering } : {}),
+        modelPrompt: promptContext.promptForModel,
         onFinalPromptText: input.lifecycle.setFinalPromptText,
         onSteeringAcknowledged: () => {
           leasedSteering = undefined;
         },
         ...(promptBuildPrependContext ? { prependContext: promptBuildPrependContext } : {}),
+        ...(promptContext.runtimeContextMessageForCurrentTurn
+          ? { runtimeContextMessage: promptContext.runtimeContextMessageForCurrentTurn }
+          : {}),
+        runtimeOnly: promptContext.promptSubmission.runtimeOnly === true,
+        systemPrompt: promptContext.systemPromptForHook,
+        toolResultAggregateMaxChars: promptContext.promptToolResultAggregateMaxChars,
+        toolResultMaxChars: promptContext.promptToolResultMaxChars,
         transcriptLeafId,
+        transcriptPrompt: promptContext.promptForSession,
         ...input.submission,
-      },
-    });
-    publishDispatchState(dispatchState);
+      });
+    } else {
+      releaseLeasedSteering(state.promptError ?? "prompt submission skipped");
+    }
+    publishDispatchState(state);
   } catch (error) {
     const promptErrorOutcome = await handleEmbeddedAttemptPromptError({
       activeSession,