fix: handle prompt-too-long by resetting session and continuing inline directives

src/auto-reply/command-reply.test.ts

@@ -251,6 +251,35 @@ describe("runCommandReply (pi)", () => {
     expect(meta.killed).toBe(true);
   });
 
+  it("surfaces prompt-too-long and flags meta for session reset", async () => {
+    mockPiRpc({
+      stdout:
+        '{"type":"agent_end","message":{"role":"assistant","content":[],"errorMessage":"400 {\\"type\\":\\"error\\",\\"error\\":{\\"type\\":\\"invalid_request_error\\",\\"message\\":\\"prompt is too long: 200333 tokens > 200000 maximum\\"}}"}}',
+      stderr: "",
+      code: 0,
+    });
+
+    const { payloads, meta } = await runCommandReply({
+      reply: {
+        mode: "command",
+        command: ["pi", "{{Body}}"],
+        agent: { kind: "pi" },
+      },
+      templatingCtx: noopTemplateCtx,
+      sendSystemOnce: false,
+      isNewSession: false,
+      isFirstTurnInSession: false,
+      systemSent: false,
+      timeoutMs: 1000,
+      timeoutSeconds: 1,
+      commandRunner: vi.fn(),
+      enqueue: enqueueImmediate,
+    });
+
+    expect(payloads?.[0]?.text).toMatch(/history is too long/i);
+    expect(meta.agentMeta?.extra?.promptTooLong).toBe(true);
+  });
+
   it("collapses rpc deltas instead of emitting raw JSON spam", async () => {
     mockPiRpc({
       stdout: [

src/auto-reply/command-reply.ts

@@ -677,18 +677,19 @@ export async function runCommandReply(
         }
       },
     });
-    const rawStdout = stdout.trim();
-    const rpcAssistantText = extractRpcAssistantText(stdout);
-    let mediaFromCommand: string[] | undefined;
-    const trimmed = stripRpcNoise(rawStdout);
-    if (stderr?.trim()) {
-      logVerbose(`Command auto-reply stderr: ${stderr.trim()}`);
-    }
+  const rawStdout = stdout.trim();
+  const rpcAssistantText = extractRpcAssistantText(stdout);
+  let mediaFromCommand: string[] | undefined;
+  const trimmed = stripRpcNoise(rawStdout);
+  if (stderr?.trim()) {
+    logVerbose(`Command auto-reply stderr: ${stderr.trim()}`);
+  }
+  const promptTooLong = rawStdout.includes("prompt is too long");
 
-    const logFailure = () => {
-      const truncate = (s?: string) =>
-        s ? (s.length > 4000 ? `${s.slice(0, 4000)}…` : s) : undefined;
-      logger.warn(
+  const logFailure = () => {
+    const truncate = (s?: string) =>
+      s ? (s.length > 4000 ? `${s.slice(0, 4000)}…` : s) : undefined;
+    logger.warn(
         {
           code,
           signal,
@@ -702,6 +703,21 @@ export async function runCommandReply(
       );
     };
 
+    if (promptTooLong) {
+      const text =
+        "⚠️ Session history is too long. Starting a fresh session — please resend your last message.";
+      const meta: CommandReplyMeta = {
+        durationMs: Date.now() - started,
+        queuedMs,
+        queuedAhead,
+        exitCode: code,
+        signal,
+        killed,
+        agentMeta: { extra: { promptTooLong: true } },
+      };
+      return { payloads: [{ text }], meta };
+    }
+
     const parsed = trimmed ? agent.parseOutput(trimmed) : undefined;
 
     // Collect assistant texts and tool results from parseOutput (tau RPC can emit many).

src/auto-reply/reply.ts

@@ -701,6 +701,26 @@ export async function getReplyFromConfig(
       });
       const payloadArray = runResult.payloads ?? [];
       const meta = runResult.meta;
+      const promptTooLong =
+        meta.agentMeta &&
+        typeof meta.agentMeta.extra === "object" &&
+        (meta.agentMeta.extra as { promptTooLong?: boolean }).promptTooLong;
+
+      if (promptTooLong && sessionCfg && sessionStore && sessionKey) {
+        // Rotate to a new session to avoid hitting context limits again.
+        const newId = crypto.randomUUID();
+        sessionEntry = {
+          sessionId: newId,
+          updatedAt: Date.now(),
+          systemSent,
+          abortedLastRun: false,
+        };
+        sessionStore[sessionKey] = sessionEntry;
+        await saveSessionStore(storePath, sessionStore);
+        sessionId = newId;
+        isNewSession = true;
+      }
+
       let finalPayloads = payloadArray;
       if (!finalPayloads || finalPayloads.length === 0) {
         return undefined;