fix(coding-agent): obfuscate guided-goal transcript before provider calls

runGuidedGoalTurn sent the rendered interview transcript to the plan/slow
provider as raw text, so a secret typed into the rough goal or an answer
bypassed the session's redaction contract. Route the transcript through the
session obfuscator before the request and deobfuscate the echoed question /
objective before it is displayed or the goal starts (no-op when no secrets
are configured).

packages/coding-agent/src/goals/guided-setup.ts

@@ -79,11 +79,16 @@ export async function runGuidedGoalTurn(
 	const userPrompt = prompt.render(guidedGoalInterviewPrompt, {
 		messages: options.messages.map(message => ({ label: message.role.toUpperCase(), content: message.content })),
 	});
+	// Secret obfuscation: route the user-authored transcript through the session obfuscator the
+	// same way normal turns do, so an API key / secret typed into the rough goal or an answer is
+	// never sent verbatim to the plan/slow provider. Deobfuscated again below before display/use.
+	const obfuscator = session.obfuscator;
+	const promptText = obfuscator?.hasSecrets() ? obfuscator.obfuscate(userPrompt) : userPrompt;
 	const response = await instrumentedCompleteSimple(
 		resolved.model,
 		{
 			systemPrompt: [prompt.render(guidedGoalSystemPrompt)],
-			messages: [{ role: "user", content: [{ type: "text", text: userPrompt }], timestamp: Date.now() }],
+			messages: [{ role: "user", content: [{ type: "text", text: promptText }], timestamp: Date.now() }],
 			tools: [RESPOND_TOOL],
 		},
 		{
@@ -103,13 +108,26 @@ export async function runGuidedGoalTurn(
 	}
 
 	const call = extractToolCall(response, RESPOND_TOOL_NAME);
+	let result: GuidedGoalTurnResult;
 	if (call) {
-		return parseGuidedGoalPayload(parseToolArguments(call.arguments));
+		result = parseGuidedGoalPayload(parseToolArguments(call.arguments));
+	} else {
+		const text = extractTextContent(response);
+		if (!text) {
+			throw new Error("guided goal returned an invalid response");
+		}
+		result = parseGuidedGoalPayload(parseJsonPayload(text));
 	}
 
-	const text = extractTextContent(response);
-	if (!text) {
-		throw new Error("guided goal returned an invalid response");
+	// Reverse the obfuscation: restore any secret placeholders the model echoed back before the
+	// question/objective is shown or the goal is started.
+	if (!obfuscator?.hasSecrets()) return result;
+	if (result.kind === "question") {
+		return {
+			kind: "question",
+			question: obfuscator.deobfuscate(result.question),
+			objective: result.objective !== undefined ? obfuscator.deobfuscate(result.objective) : undefined,
+		};
 	}
-	return parseGuidedGoalPayload(parseJsonPayload(text));
+	return { kind: "ready", objective: obfuscator.deobfuscate(result.objective) };
 }

packages/coding-agent/test/goals/guided-goal.test.ts

@@ -171,6 +171,32 @@ describe("guided goal setup", () => {
 		expect(result).toEqual({ kind: "question", question: "What is done?", objective: "Ship the feature." });
 	});
 
+	it("obfuscates secrets in the transcript before the request and deobfuscates the echoed objective", async () => {
+		const obfuscator = {
+			hasSecrets: () => true,
+			obfuscate: (text: string) => text.replaceAll("SECRET123", "#S0#"),
+			deobfuscate: (text: string) => text.replaceAll("#S0#", "SECRET123"),
+		};
+		const session = { ...createSession(), obfuscator } as unknown as AgentSession;
+		const complete = spyOn(core, "instrumentedCompleteSimple").mockResolvedValue(
+			// The model echoes the obfuscated placeholder back inside its objective.
+			mockResponse({ kind: "ready", objective: "Rotate the key #S0# and redeploy." }) as never,
+		);
+
+		const result = await runGuidedGoalTurn(session, {
+			messages: [{ role: "user", content: "my api key is SECRET123, automate rotation" }],
+		});
+
+		// The provider never sees the raw secret — only the placeholder.
+		const sentContext = complete.mock.calls[0]?.[1] as { messages: Array<{ content: Array<{ text: string }> }> };
+		const sentText = sentContext.messages[0]!.content[0]!.text;
+		expect(sentText).not.toContain("SECRET123");
+		expect(sentText).toContain("#S0#");
+
+		// The objective is restored to the real secret before the goal starts.
+		expect(result).toEqual({ kind: "ready", objective: "Rotate the key SECRET123 and redeploy." });
+	});
+
 	it("salvages the latest guided objective when the turn cap ends on a question without one", async () => {
 		const harness = await createInteractiveGoalHarness();
 		try {