fix(daemon): read Pi model list from stdout (#5637)

apps/daemon/src/runtimes/defs/pi.ts

@@ -12,16 +12,15 @@ export const piAgentDef = {
     // every spawn). The default 3s version-probe timeout is too tight; raise it
     // so detection doesn't silently abort before reaching fetchModels.
     versionProbeTimeoutMs: 15_000,
-    // `pi --list-models` prints a TSV table to stderr (not stdout),
-    // so we use a custom fetchModels that reads stderr.
+    // `pi --list-models` prints its TSV table to stdout.
     fetchModels: async (resolvedBin, env) => {
       try {
-        const { stderr } = await execAgentFile(resolvedBin, ['--list-models'], {
+        const { stdout } = await execAgentFile(resolvedBin, ['--list-models'], {
           env,
           timeout: 60_000, // Windows: 20s exceeded under parallel detection load
           maxBuffer: 8 * 1024 * 1024,
         });
-        const parsed = parsePiModels(stderr);
+        const parsed = parsePiModels(stdout);
         if (!parsed || parsed.length === 0) return null;
         return parsed;
       } catch {

apps/daemon/tests/runtimes/agent-args.test.ts

@@ -269,6 +269,38 @@ test('pi args use rpc mode without --no-session and append model/thinking option
   ]);
 });
 
+test('pi fetchModels reads the model table from stdout', async () => {
+  const dir = mkdtempSync(join(tmpdir(), 'od-pi-models-'));
+  try {
+    const bin = join(dir, process.platform === 'win32' ? 'pi.cmd' : 'pi');
+    if (process.platform === 'win32') {
+      writeFileSync(
+        bin,
+        '@echo off\r\nif "%~1"=="--list-models" (\r\n  echo provider model context max-out thinking images\r\n  echo anthropic claude-sonnet-4-5 200K 64K yes yes\r\n  exit /b 0\r\n)\r\nexit /b 1\r\n',
+      );
+    } else {
+      writeFileSync(
+        bin,
+        '#!/bin/sh\nif [ "$1" = "--list-models" ]; then\n  printf \'%s\\n\' \\\n    \'provider model context max-out thinking images\' \\\n    \'anthropic claude-sonnet-4-5 200K 64K yes yes\'\n  exit 0\nfi\nexit 1\n',
+      );
+      chmodSync(bin, 0o755);
+    }
+
+    assert.ok(pi.fetchModels, 'pi must define fetchModels');
+    const models = await pi.fetchModels(bin, {});
+
+    assert.deepEqual(models, [
+      { id: 'default', label: 'Default (CLI config)' },
+      {
+        id: 'anthropic/claude-sonnet-4-5',
+        label: 'anthropic/claude-sonnet-4-5',
+      },
+    ]);
+  } finally {
+    rmSync(dir, { recursive: true, force: true });
+  }
+});
+
 test('pi args forward extraAllowedDirs as --append-system-prompt flags', () => {
   const args = pi.buildArgs(
     '',