fix: parse session_id from stderr (hermes --quiet writes it there)

hermes --quiet outputs session_id to stderr and AI response to stdout.
The agent was only parsing stdout, so session_id was never found and
detail always fell back to raw output.

Now checks stderr first, then stdout as fallback.

packages/uwf-agent-hermes/__tests__/session-detail.test.ts

@@ -16,7 +16,12 @@ describe("parseSessionIdFromStdout", () => {
     expect(parseSessionIdFromStdout(stdout)).toBe("20260518_223724_45ab80");
   });
 
-  test("returns null when trailing line is not session_id", () => {
+  test("reads session_id from the first line (quiet mode)", () => {
+    const stdout = "session_id: 20260518_165315_3467a1\nHello world\n";
+    expect(parseSessionIdFromStdout(stdout)).toBe("20260518_165315_3467a1");
+  });
+
+  test("returns null when no session_id line present", () => {
     expect(parseSessionIdFromStdout("only assistant text\n")).toBeNull();
   });
 });

packages/uwf-agent-hermes/src/hermes.ts

@@ -43,7 +43,7 @@ export function buildHermesPrompt(ctx: AgentContext): string {
   return parts.join("\n");
 }
 
-function spawnHermesChat(prompt: string): Promise<string> {
+function spawnHermesChat(prompt: string): Promise<{ stdout: string; stderr: string }> {
   return new Promise((resolve, reject) => {
     const args = [
       "chat",
@@ -76,7 +76,7 @@ function spawnHermesChat(prompt: string): Promise<string> {
 
     child.on("close", (code) => {
       if (code === 0) {
-        resolve(stdout);
+        resolve({ stdout, stderr });
         return;
       }
       const detail = stderr.trim() !== "" ? ` stderr=${stderr.trim()}` : "";
@@ -87,10 +87,11 @@ function spawnHermesChat(prompt: string): Promise<string> {
 
 async function runHermes(ctx: AgentContext): Promise<AgentRunResult> {
   const fullPrompt = buildHermesPrompt(ctx);
-  const rawOutput = await spawnHermesChat(fullPrompt);
+  const { stdout, stderr } = await spawnHermesChat(fullPrompt);
   const { store } = ctx;
 
-  const sessionId = parseSessionIdFromStdout(rawOutput);
+  // --quiet mode: session_id may be on stdout or stderr
+  const sessionId = parseSessionIdFromStdout(stderr) ?? parseSessionIdFromStdout(stdout);
   if (sessionId !== null) {
     const session = await loadHermesSession(sessionId);
     if (session !== null) {
@@ -99,8 +100,8 @@ async function runHermes(ctx: AgentContext): Promise<AgentRunResult> {
     }
   }
 
-  const detailHash = await storeHermesRawOutput(store, rawOutput);
-  return { output: rawOutput, detailHash };
+  const detailHash = await storeHermesRawOutput(store, stdout);
+  return { output: stdout, detailHash };
 }
 
 /** Agent CLI factory: parses argv, runs Hermes, extracts output, writes StepNode. */

packages/uwf-agent-hermes/src/session-detail.ts

@@ -24,19 +24,14 @@ export function getHermesSessionPath(sessionId: string): string {
   return join(getHermesSessionsDir(), `session_${sessionId}.json`);
 }
 
-/** Parse `session_id: …` from the last non-empty line of Hermes stdout. */
+/** Parse `session_id: …` from any line of Hermes stdout. */
 export function parseSessionIdFromStdout(stdout: string): string | null {
-  const lines = stdout.split(/\r?\n/).map((line) => line.trim());
-  for (let i = lines.length - 1; i >= 0; i--) {
-    const line = lines[i];
-    if (line === undefined || line === "") {
-      continue;
-    }
-    const match = SESSION_ID_LINE.exec(line);
+  const lines = stdout.split(/\r?\n/);
+  for (const line of lines) {
+    const match = SESSION_ID_LINE.exec(line.trim());
     if (match?.[1] !== undefined) {
       return match[1];
     }
-    break;
   }
   return null;
 }