fix: add CLI empty response diagnostics

shakkernerd · shakkernerd · commit 81c9bd3997b2 · 2026-06-17T03:31:14.000+01:00
diff --git a/src/agents/cli-output.ts b/src/agents/cli-output.ts
@@ -21,12 +21,28 @@ type CliUsage = {
   total?: number;
 };
 
+export type CliProcessDiagnostics = {
+  backendId: string;
+  processReason: string;
+  exitCode: number | null;
+  exitSignal: NodeJS.Signals | number | null;
+  durationMs: number;
+  stdoutBytes: number;
+  stdoutHash: string;
+  stderrBytes: number;
+  stderrHash: string;
+  useResume: boolean;
+};
+
 /** Normalized result from a CLI-backed model provider turn. */
 export type CliOutput = {
   text: string;
   rawText?: string;
   sessionId?: string;
   usage?: CliUsage;
+  diagnostics?: {
+    process?: CliProcessDiagnostics;
+  };
   finalPromptText?: string;
   didSendViaMessagingTool?: boolean;
   didDeliverSourceReplyViaMessageTool?: boolean;
diff --git a/src/agents/cli-runner.spawn.test.ts b/src/agents/cli-runner.spawn.test.ts
@@ -870,6 +870,42 @@ describe("runCliAgent spawn path", () => {
     }
   });
 
+  it("returns process diagnostics with byte counts and bounded output hashes", async () => {
+    supervisorSpawnMock.mockResolvedValueOnce(
+      createManagedRun({
+        reason: "exit",
+        exitCode: 0,
+        exitSignal: null,
+        durationMs: 75,
+        stdout: "ok",
+        stderr: "warn\n",
+        timedOut: false,
+        noOutputTimedOut: false,
+      }),
+    );
+
+    const result = await executePreparedCliRun(
+      buildPreparedCliRunContext({
+        provider: "codex-cli",
+        model: "gpt-5.4",
+        runId: "run-process-diagnostics",
+      }),
+    );
+
+    expect(result.diagnostics?.process).toEqual({
+      backendId: "codex-cli",
+      processReason: "exit",
+      exitCode: 0,
+      exitSignal: null,
+      durationMs: 75,
+      stdoutBytes: 2,
+      stdoutHash: "2689367b205c",
+      stderrBytes: 5,
+      stderrHash: "7597e6b3a377",
+      useResume: false,
+    });
+  });
+
   it("passes Codex system prompts through model_instructions_file", async () => {
     let promptFileText = "";
     supervisorSpawnMock.mockImplementationOnce(async (...args: unknown[]) => {
diff --git a/src/agents/cli-runner.ts b/src/agents/cli-runner.ts
@@ -101,6 +101,25 @@ function shouldRetryFreshCliSessionAfterFailover(params: {
   }
 }
 
+function formatCliEmptyOutputDiagnostics(output: CliOutput): string | undefined {
+  const process = output.diagnostics?.process;
+  if (!process) {
+    return undefined;
+  }
+  return [
+    `backend=${process.backendId}`,
+    `reason=${process.processReason}`,
+    `exitCode=${process.exitCode ?? "null"}`,
+    `exitSignal=${process.exitSignal ?? "null"}`,
+    `durationMs=${process.durationMs}`,
+    `stdoutBytes=${process.stdoutBytes}`,
+    `stdoutHash=${process.stdoutHash}`,
+    `stderrBytes=${process.stderrBytes}`,
+    `stderrHash=${process.stderrHash}`,
+    `useResume=${process.useResume ? "true" : "false"}`,
+  ].join(" ");
+}
+
 /** Checks whether a Claude CLI session binding has reached its transcript file. */
 export async function isCliBindingFlushed(
   sessionId: string | undefined,
@@ -780,6 +799,10 @@ export async function runPreparedCliAgent(
       !output.didSendViaMessagingTool &&
       params.allowEmptyAssistantReplyAsSilent !== true
     ) {
+      const emptyOutputDiagnostics = formatCliEmptyOutputDiagnostics(output);
+      if (emptyOutputDiagnostics) {
+        cliBackendLog.warn(`cli empty response diagnostics: ${emptyOutputDiagnostics}`);
+      }
       throw attachCliMessagingDeliveryEvidence(
         new FailoverError("CLI backend returned an empty response.", {
           reason: "empty_response",
diff --git a/src/agents/cli-runner/execute.ts b/src/agents/cli-runner/execute.ts
@@ -1110,9 +1110,13 @@ export async function executePreparedCliRun(
           });
           let stdoutTail: Buffer = Buffer.alloc(0);
           let stdoutParseBuffer: Buffer = Buffer.alloc(0);
+          let stdoutBytes = 0;
+          const stdoutHash = crypto.createHash("sha256");
           let stdoutParseExceeded = false;
           let stderrTail: Buffer = Buffer.alloc(0);
           let stderrParseBuffer: Buffer = Buffer.alloc(0);
+          let stderrBytes = 0;
+          const stderrHash = crypto.createHash("sha256");
           let stderrParseExceeded = false;
 
           params.onExecutionPhase?.({
@@ -1135,6 +1139,8 @@ export async function executePreparedCliRun(
             input: stdinPayload,
             captureOutput: false,
             onStdout: (chunk: string) => {
+              stdoutBytes += Buffer.byteLength(chunk);
+              stdoutHash.update(chunk);
               stdoutTail = appendCliOutputTail(stdoutTail, chunk);
               if (!stdoutParseExceeded) {
                 const nextStdoutParse = appendCliOutputParseBuffer(stdoutParseBuffer, chunk);
@@ -1144,6 +1150,8 @@ export async function executePreparedCliRun(
               streamingParser?.push(chunk);
             },
             onStderr: (chunk: string) => {
+              stderrBytes += Buffer.byteLength(chunk);
+              stderrHash.update(chunk);
               stderrTail = appendCliOutputTail(stderrTail, chunk);
               if (!stderrParseExceeded) {
                 const nextStderrParse = appendCliOutputParseBuffer(stderrParseBuffer, chunk);
@@ -1191,6 +1199,18 @@ export async function executePreparedCliRun(
           const stdoutDiagnostic = stdoutTail.toString("utf8").trim();
           const stderr = stderrParseBuffer.toString("utf8").trim();
           const stderrDiagnostic = stderrTail.toString("utf8").trim();
+          const processDiagnostics = {
+            backendId: context.backendResolved.id,
+            processReason: result.reason,
+            exitCode: result.exitCode,
+            exitSignal: result.exitSignal,
+            durationMs: result.durationMs,
+            stdoutBytes,
+            stdoutHash: stdoutHash.digest("hex").slice(0, 12),
+            stderrBytes,
+            stderrHash: stderrHash.digest("hex").slice(0, 12),
+            useResume,
+          };
           if (logOutputText) {
             if (stdoutDiagnostic) {
               cliBackendLog.info(`cli stdout:\n${stdoutDiagnostic}`);
@@ -1347,6 +1367,10 @@ export async function executePreparedCliRun(
           );
           runOutput = {
             ...parsed,
+            diagnostics: {
+              ...(parsed.diagnostics ?? {}),
+              process: processDiagnostics,
+            },
             rawText,
             finalPromptText: prompt,
             text: applyPluginTextReplacements(
