diff --git a/electron/agent-hooks.mjs b/electron/agent-hooks.mjs
index 9741bb1..a607dcb 100644
--- a/electron/agent-hooks.mjs
+++ b/electron/agent-hooks.mjs
@@ -30,10 +30,12 @@ export function registerAgentHookIpc() {
 		if (!pending || pending.webContentsId !== event.sender.id) {
 			return { status: "ignored" };
 		}
+		const result = normalizeAgentHookListenerResult(payload?.result);
 		clearTimeout(pending.timeout);
 		pendingDeliveries.delete(deliveryId);
 		pending.resolve({
 			status: payload?.status === "error" ? "error" : "ok",
+			...result,
 		});
 		return { status: "acknowledged" };
 	});
@@ -270,6 +272,9 @@ async function processAgentHookMessage(endpoint, input) {
 	return {
 		ok: delivery.status !== "timeout" && delivery.status !== "disposed",
 		status: delivery.status,
+		...(delivery.additionalContext
+			? { additionalContext: delivery.additionalContext }
+			: {}),
 	};
 }
 
@@ -359,6 +364,27 @@ function parseHookStdin(value) {
 	}
 }
 
+function normalizeAgentHookListenerResult(value) {
+	if (typeof value === "string") {
+		return normalizeAgentHookAdditionalContext(value);
+	}
+	if (!value || typeof value !== "object") {
+		return {};
+	}
+	return normalizeAgentHookAdditionalContext(value.additionalContext);
+}
+
+function normalizeAgentHookAdditionalContext(value) {
+	if (typeof value !== "string") {
+		return {};
+	}
+	const additionalContext = value.trim();
+	if (!additionalContext) {
+		return {};
+	}
+	return { additionalContext };
+}
+
 export function agentHookScriptSource() {
 	return String.raw`import { readFileSync } from "node:fs";
 import { connect } from "node:net";
@@ -383,7 +409,15 @@ const payload = {
 };
 
 try {
-	await sendHookEvent(payload);
+	const response = await sendHookEvent(payload);
+	const additionalContext = readAdditionalContext(response);
+	if (payload.phase === "turn-start" && additionalContext) {
+		process.stdout.write(
+			additionalContext.endsWith("\n")
+				? additionalContext
+				: additionalContext + "\n",
+		);
+	}
 } catch {
 	// Hook delivery must not prevent the agent command from continuing.
 }
@@ -393,7 +427,7 @@ function sendHookEvent(payload) {
 		const socket = connect(socketPath);
 		let response = "";
 		let settled = false;
-		const finish = (error) => {
+		const finish = (error, value) => {
 			if (settled) return;
 			settled = true;
 			socket.destroy();
@@ -401,7 +435,7 @@ function sendHookEvent(payload) {
 				reject(error);
 				return;
 			}
-			resolve();
+			resolve(value);
 		};
 
 		socket.setEncoding("utf8");
@@ -419,13 +453,14 @@ function sendHookEvent(payload) {
 				finish(new Error("Hook acknowledgement was empty"));
 				return;
 			}
+			let parsed;
 			try {
-				JSON.parse(response);
+				parsed = JSON.parse(response);
 			} catch {
 				finish(new Error("Hook acknowledgement was invalid JSON"));
 				return;
 			}
-			finish();
+			finish(null, parsed);
 		});
 		socket.on("error", finish);
 		socket.on("close", () => {
@@ -434,5 +469,12 @@ function sendHookEvent(payload) {
 	});
 }
 
+function readAdditionalContext(response) {
+	const value = response?.additionalContext;
+	return typeof value === "string" && value.trim().length > 0
+		? value.trim()
+		: null;
+}
+
 `;
 }
diff --git a/electron/agent-hooks.test.mjs b/electron/agent-hooks.test.mjs
index 2720f4c..80b8c44 100644
--- a/electron/agent-hooks.test.mjs
+++ b/electron/agent-hooks.test.mjs
@@ -198,6 +198,55 @@ describe("agentHookScriptSource", () => {
 		}
 	});
 
+	test("prints additional context from turn-start acknowledgements", async () => {
+		const rootDir = await mkdtemp(path.join(tmpdir(), "flashtype-agent-hook-"));
+		const socketPath = testSocketPath(rootDir);
+		const received = deferred();
+		const server = net.createServer({ allowHalfOpen: true }, (socket) => {
+			let input = "";
+			socket.setEncoding("utf8");
+			socket.on("data", (chunk) => {
+				input += chunk;
+			});
+			socket.on("end", () => {
+				received.resolve(JSON.parse(input));
+				socket.end(
+					`${JSON.stringify({
+						ok: true,
+						additionalContext: "The active file right now is ./current.md",
+					})}\n`,
+				);
+			});
+		});
+		try {
+			const scriptPath = path.join(rootDir, "hook.mjs");
+			await writeFile(scriptPath, agentHookScriptSource(), { mode: 0o700 });
+			await listen(server, socketPath);
+
+			const result = await runHookScript({
+				scriptPath,
+				args: ["codex", "turn-start"],
+				env: {
+					FLASHTYPE_AGENT_HOOK_SOCKET: socketPath,
+					FLASHTYPE_AGENT_HOOK_TOKEN: "secret",
+					FLASHTYPE_AGENT_HOOK_INSTANCE_ID: "terminal:1",
+				},
+				stdin: JSON.stringify({
+					hook_event_name: "UserPromptSubmit",
+				}),
+			});
+
+			expect(await received.promise).toMatchObject({
+				agent: "codex",
+				phase: "turn-start",
+			});
+			expect(result.stdout).toBe("The active file right now is ./current.md\n");
+		} finally {
+			server.close();
+			await rm(rootDir, { recursive: true, force: true });
+		}
+	});
+
 	test("exits successfully when socket delivery fails", async () => {
 		const rootDir = await mkdtemp(path.join(tmpdir(), "flashtype-agent-hook-"));
 		try {
@@ -280,7 +329,7 @@ function runHookScript({ scriptPath, args, env, stdin }) {
 		child.on("error", reject);
 		child.on("close", (code, signal) => {
 			if (code === 0) {
-				resolve();
+				resolve({ stdout, stderr });
 				return;
 			}
 			reject(
diff --git a/electron/preload.mjs b/electron/preload.mjs
index 8aa2e23..819dbc1 100644
--- a/electron/preload.mjs
+++ b/electron/preload.mjs
@@ -119,9 +119,10 @@ const agentHooks = {
 				return;
 			}
 			void Promise.resolve(listener(payload.event))
-				.then(() =>
+				.then((result) =>
 					ipcRenderer.invoke("agentHooks:completeTurnEvent", {
 						deliveryId: payload.deliveryId,
+						result: normalizeAgentHookListenerResult(result),
 						status: "ok",
 					}),
 				)
@@ -140,6 +141,20 @@ const agentHooks = {
 	},
 };
 
+function normalizeAgentHookListenerResult(value) {
+	if (typeof value === "string") {
+		return { additionalContext: value };
+	}
+	if (!value || typeof value !== "object") {
+		return undefined;
+	}
+	const additionalContext = value.additionalContext;
+	if (typeof additionalContext !== "string") {
+		return undefined;
+	}
+	return { additionalContext };
+}
+
 contextBridge.exposeInMainWorld("flashtypeDesktop", {
 	agentHooks,
 	app,
diff --git a/electron/types.d.ts b/electron/types.d.ts
index 0fe66af..c178b83 100644
--- a/electron/types.d.ts
+++ b/electron/types.d.ts
@@ -147,9 +147,18 @@ export type DesktopAgentTurnEvent = {
 	createdAt: number;
 };
 
+export type DesktopAgentTurnEventResult =
+	| void
+	| string
+	| {
+			additionalContext?: string | null;
+	  };
+
 export type DesktopAgentHooksApi = {
 	onTurnEvent(
-		listener: (event: DesktopAgentTurnEvent) => void | Promise<void>,
+		listener: (
+			event: DesktopAgentTurnEvent,
+		) => DesktopAgentTurnEventResult | Promise<DesktopAgentTurnEventResult>,
 	): () => void;
 };
 
diff --git a/src/shell/agent-launch.test.ts b/src/shell/agent-launch.test.ts
index c7d5001..67b71de 100644
--- a/src/shell/agent-launch.test.ts
+++ b/src/shell/agent-launch.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, test } from "vitest";
 import {
+	FLASHTYPE_INITIAL_PROMPT,
 	TERMINAL_INITIAL_COMMAND_LAUNCH_ARG,
 	buildAgentLaunchArgsWithActiveFile,
 	buildFlashtypeActiveFilePrompt,
@@ -11,9 +12,9 @@ import {
 } from "@/extension-runtime/agent-terminal-command";
 
 describe("buildFlashtypeActiveFilePrompt", () => {
-	test("uses the Flashtype.com launch-context sentence", () => {
+	test("uses the active-file context sentence", () => {
 		expect(buildFlashtypeActiveFilePrompt("/docs/intro.md")).toBe(
-			"The user is using Flashtype.com. The active file right now, which may change later, is: ./docs/intro.md",
+			"The current document is: ./docs/intro.md",
 		);
 	});
 
@@ -29,7 +30,7 @@ describe("buildFlashtypeActiveFilePrompt", () => {
 });
 
 describe("buildAgentLaunchArgsWithActiveFile", () => {
-	test("adds a Claude append-system-prompt launch command", () => {
+	test("adds Claude hook launch args with Flashtype system prompt only", () => {
 		const launchArgs = buildAgentLaunchArgsWithActiveFile({
 			state: {
 				command: "claude --dangerously-skip-permissions",
@@ -56,11 +57,12 @@ describe("buildAgentLaunchArgsWithActiveFile", () => {
 			'ELECTRON_RUN_AS_NODE=1 \\"$FLASHTYPE_AGENT_HOOK_NODE\\" \\"$FLASHTYPE_AGENT_HOOK_SCRIPT\\" claude turn-start',
 		);
 		expect(pathWrapper.command).toContain(
-			"--append-system-prompt 'The user is using Flashtype.com. The active file right now, which may change later, is: ./docs/intro.md'",
+			`--append-system-prompt '${FLASHTYPE_INITIAL_PROMPT}'`,
 		);
+		expect(pathWrapper.command).not.toContain("./docs/intro.md");
 	});
 
-	test("adds a Codex developer-instructions launch command", () => {
+	test("adds Codex hook launch args with Flashtype developer instructions only", () => {
 		const launchArgs = buildAgentLaunchArgsWithActiveFile({
 			state: {
 				command: "codex --dangerously-bypass-approvals-and-sandbox",
@@ -86,8 +88,9 @@ describe("buildAgentLaunchArgsWithActiveFile", () => {
 			'ELECTRON_RUN_AS_NODE=1 \\"$FLASHTYPE_AGENT_HOOK_NODE\\" \\"$FLASHTYPE_AGENT_HOOK_SCRIPT\\" codex turn-start',
 		);
 		expect(pathWrapper.command).toContain(
-			"-c 'developer_instructions=\"The user is using Flashtype.com. The active file right now, which may change later, is: ./docs/intro.md\"'",
+			`-c 'developer_instructions="${FLASHTYPE_INITIAL_PROMPT}"'`,
 		);
+		expect(pathWrapper.command).not.toContain("./docs/intro.md");
 	});
 
 	test("injects hooks for agent launches without an active file", () => {
@@ -105,7 +108,9 @@ describe("buildAgentLaunchArgsWithActiveFile", () => {
 		};
 		expect(command).toBe("codex-flashtype");
 		expect(pathWrapper.command).toContain("hooks.UserPromptSubmit=");
-		expect(pathWrapper.command).not.toContain("developer_instructions=");
+		expect(pathWrapper.command).toContain(
+			`developer_instructions="${FLASHTYPE_INITIAL_PROMPT}"`,
+		);
 	});
 
 	test("injects hooks into restored agent terminal commands", () => {
diff --git a/src/shell/agent-launch.ts b/src/shell/agent-launch.ts
index 1348ada..6460ae3 100644
--- a/src/shell/agent-launch.ts
+++ b/src/shell/agent-launch.ts
@@ -9,12 +9,17 @@ import {
 
 export { TERMINAL_INITIAL_COMMAND_LAUNCH_ARG };
 
+export const FLASHTYPE_INITIAL_PROMPT =
+	"You are running inside Flashtype, a local Markdown editor with inline diff review. Use workspace files as the source of truth. Make requested changes; the user reviews diffs before they land.";
+
 export function buildAgentLaunchArgsWithActiveFile(args: {
 	readonly state?: ExtensionState;
 	readonly activeFilePath?: string | null;
 }): ExtensionLaunchArgs | undefined {
-	const prompt = buildFlashtypeActiveFilePrompt(args.activeFilePath);
-	return buildAgentTerminalLaunchArgs({ state: args.state, prompt });
+	return buildAgentTerminalLaunchArgs({
+		state: args.state,
+		prompt: FLASHTYPE_INITIAL_PROMPT,
+	});
 }
 
 export function buildFlashtypeActiveFilePrompt(
@@ -24,7 +29,7 @@ export function buildFlashtypeActiveFilePrompt(
 	if (!promptPath) {
 		return null;
 	}
-	return `The user is using Flashtype.com. The active file right now, which may change later, is: ${promptPath}`;
+	return `The current document is: ${promptPath}`;
 }
 
 function normalizePromptFilePath(
diff --git a/src/shell/layout-shell.test.tsx b/src/shell/layout-shell.test.tsx
index 900f3fe..2454457 100644
--- a/src/shell/layout-shell.test.tsx
+++ b/src/shell/layout-shell.test.tsx
@@ -21,7 +21,7 @@ type DesktopMock = {
 };
 
 type AgentHooksDesktopMock = {
-	readonly emitTurnEvent: (event: AgentHookTurnEventInput) => Promise<void>;
+	readonly emitTurnEvent: (event: AgentHookTurnEventInput) => Promise<unknown>;
 	readonly onTurnEvent: ReturnType<typeof vi.fn>;
 	readonly setActiveFilePath: ReturnType<typeof vi.fn>;
 };
@@ -399,6 +399,32 @@ describe("V2LayoutShell active file sidebar highlight", () => {
 });
 
 describe("V2LayoutShell agent review auto-open", () => {
+	test("returns current active file context from turn-start hooks", async () => {
+		const desktop = installAgentHooksDesktopMock();
+		const lix = await openLix({
+			keyValues: [
+				uiStateKeyValue(openFileState("file_current", "/current.md")),
+			],
+		});
+		vi.spyOn(lix, "syncDiskToLix").mockResolvedValue();
+		await writeReviewFile(lix, "file_current", "/current.md", "# Current");
+
+		const utils = await renderShell(lix);
+		await waitFor(() => expect(desktop.onTurnEvent).toHaveBeenCalled());
+
+		let result: unknown;
+		await act(async () => {
+			result = await desktop.emitTurnEvent(agentTurnEvent("turn-start"));
+		});
+
+		expect(result).toEqual({
+			additionalContext: "The current document is: ./current.md",
+		});
+
+		await unmountShell(utils);
+		await lix.close();
+	});
+
 	test("leaves the current file open when it already has a pending review", async () => {
 		const desktop = installAgentHooksDesktopMock();
 		const lix = await openLix({
@@ -550,9 +576,9 @@ function installDesktopMock(): DesktopMock {
 }
 
 function installAgentHooksDesktopMock(): AgentHooksDesktopMock {
-	let listener: ((event: unknown) => void | Promise<void>) | null = null;
+	let listener: ((event: unknown) => unknown | Promise<unknown>) | null = null;
 	const onTurnEvent = vi.fn(
-		(nextListener: (event: unknown) => void | Promise<void>) => {
+		(nextListener: (event: unknown) => unknown | Promise<unknown>) => {
 			listener = nextListener;
 			return () => {
 				if (listener === nextListener) {
@@ -576,7 +602,7 @@ function installAgentHooksDesktopMock(): AgentHooksDesktopMock {
 			if (!listener) {
 				throw new Error("agent hook listener was not registered");
 			}
-			await listener(event);
+			return await listener(event);
 		},
 		onTurnEvent,
 		setActiveFilePath,
diff --git a/src/shell/layout-shell.tsx b/src/shell/layout-shell.tsx
index f4a4320..83bea3f 100644
--- a/src/shell/layout-shell.tsx
+++ b/src/shell/layout-shell.tsx
@@ -88,7 +88,10 @@ import {
 	cloneExtensionInstance,
 	reorderPanelExtensionsByIndex,
 } from "./panel-utils";
-import { buildAgentLaunchArgsWithActiveFile } from "./agent-launch";
+import {
+	buildAgentLaunchArgsWithActiveFile,
+	buildFlashtypeActiveFilePrompt,
+} from "./agent-launch";
 import {
 	clearAgentTurnCommitRangeFile,
 	appendAgentTurnCommitRange,
@@ -125,6 +128,10 @@ type ActiveAgentTurn = {
 	readonly beforeCommitIdPromise: Promise<string | null>;
 };
 
+type AgentHookTurnEventResult = void | {
+	readonly additionalContext?: string | null;
+};
+
 const stripLaunchArgs = (view: ExtensionInstance): ExtensionInstance => {
 	const { launchArgs: _omitLaunch, ...rest } = view as any;
 	const state = sanitizeExtensionStateForPersistence(rest.state);
@@ -190,6 +197,18 @@ const isPlainObject = (value: unknown): value is Record<string, unknown> => {
 	return prototype === Object.prototype || prototype === null;
 };
 
+const activeEntryFromPanel = (panel: PanelState): ExtensionInstance | null => {
+	const activeInstance =
+		panel.activeInstance ?? panel.views[0]?.instance ?? null;
+	if (!activeInstance) return null;
+	return panel.views.find((entry) => entry.instance === activeInstance) ?? null;
+};
+
+const activeFilePathFromPanel = (panel: PanelState): string | null => {
+	const rawPath = activeEntryFromPanel(panel)?.state?.filePath;
+	return typeof rawPath === "string" && rawPath.length > 0 ? rawPath : null;
+};
+
 const newFileDraftHandlerKey = (
 	registration: NewFileDraftHandlerRegistration,
 ): string => `${registration.panelSide}:${registration.viewInstance}`;
@@ -848,9 +867,12 @@ function LayoutShellLoadedContent({
 	resolveDiffReviewTelemetryRef.current = resolveDiffReviewTelemetry;
 
 	const handleAgentHookTurnEvent = useCallback(
-		async (event: AgentHookTurnEvent) => {
+		async (event: AgentHookTurnEvent): Promise<AgentHookTurnEventResult> => {
 			const key = agentTurnKey(event);
 			if (event.phase === "turn-start") {
+				const additionalContext = buildFlashtypeActiveFilePrompt(
+					activeFilePathFromPanel(panelStatesRef.current.central),
+				);
 				const beforeCommitIdPromise = readSyncedActiveCommitId(lix).catch(
 					(error: unknown) => {
 						console.warn(
@@ -866,7 +888,7 @@ function LayoutShellLoadedContent({
 					beforeCommitIdPromise,
 				});
 				await beforeCommitIdPromise;
-				return;
+				return additionalContext ? { additionalContext } : undefined;
 			}
 
 			try {
@@ -1835,13 +1857,7 @@ function LayoutShellLoadedContent({
 	);
 
 	const activeCentralEntry = useMemo(() => {
-		const activeInstance =
-			centralPanel.activeInstance ?? centralPanel.views[0]?.instance ?? null;
-		if (!activeInstance) return null;
-		return (
-			centralPanel.views.find((entry) => entry.instance === activeInstance) ??
-			null
-		);
+		return activeEntryFromPanel(centralPanel);
 	}, [centralPanel]);
 
 	const handleAddView = useCallback(
@@ -2148,10 +2164,8 @@ function LayoutShellLoadedContent({
 	}, [activeCentralEntry, extensionMap]);
 
 	const activeFilePath = useMemo(() => {
-		if (!activeCentralEntry) return null;
-		const rawPath = activeCentralEntry.state?.filePath;
-		return typeof rawPath === "string" && rawPath.length > 0 ? rawPath : null;
-	}, [activeCentralEntry]);
+		return activeFilePathFromPanel(centralPanel);
+	}, [centralPanel]);
 
 	useEffect(() => {
 		void window.flashtypeDesktop?.workspace.setActiveFilePath({