fix: preserve Hermes runtime chat session state

packages/dashboard/src/routes/register-chat-routes.ts

@@ -115,7 +115,9 @@ export function registerChatRoutes(ctx: ApiRoutesContext, deps: ChatRouteDeps):
     }
     const projectStore = await getOrCreateProjectStore(projectId);
     const chatStore = getOrCreateScopedChatStore(projectStore);
-    return getOrCreateScopedChatManager(projectStore, chatStore, options?.pluginRunner);
+    const engine = options?.engineManager?.getEngine(projectId);
+    const pluginRunner = engine?.getPluginRunner?.() ?? options?.pluginRunner;
+    return getOrCreateScopedChatManager(projectStore, chatStore, pluginRunner);
   }
   function validateModelPair(modelProvider: unknown, modelId: unknown): { modelProvider?: string; modelId?: string } {
     let normalizedProvider: string | undefined;

packages/engine/src/project-engine.ts

@@ -1042,6 +1042,11 @@ export class ProjectEngine {
     return this.runtime.getChatStore();
   }
 
+  /** Get the project-scoped PluginRunner (if initialized). */
+  getPluginRunner() {
+    return this.runtime.getPluginRunner();
+  }
+
   attachChatStore(chatStore: NotificationChatStore): void {
     this.notificationService?.attachChatStore(chatStore);
   }

packages/engine/src/runtimes/in-process-runtime.ts

@@ -1368,6 +1368,15 @@ export class InProcessRuntime
     return this.chatStore;
   }
 
+  /**
+   * Get the project-scoped PluginRunner (if initialized).
+   * Dashboard chat needs this runner, not the top-level PluginLoader, so
+   * runtime hints such as `hermes` can resolve plugin runtimes correctly.
+   */
+  getPluginRunner(): PluginRunner | undefined {
+    return this.pluginRunner;
+  }
+
   /**
    * Get the project's Scheduler instance.
    * @throws Error if runtime has not been started

plugins/fusion-plugin-hermes-runtime/src/__tests__/cli-spawn.test.ts

@@ -224,6 +224,12 @@ describe("parseHermesOutput", () => {
     expect(result.body).toBe("line1\nline2");
   });
 
+  it("accepts session_id emitted on stderr while keeping stderr out of the body", () => {
+    const result = parseHermesOutput("OK\n", "session_id: 20260427_120000_abcd12\n");
+    expect(result.sessionId).toBe("20260427_120000_abcd12");
+    expect(result.body).toBe("OK");
+  });
+
   it("throws when session_id line is missing", () => {
     expect(() => parseHermesOutput("some output without id", "stderr text")).toThrow(
       /missing session_id/,

plugins/fusion-plugin-hermes-runtime/src/cli-spawn.ts

@@ -309,18 +309,19 @@ function stripChrome(text: string): string {
  * Returns `{ body, sessionId }` on success or throws with a descriptive error.
  */
 export function parseHermesOutput(rawStdout: string, rawStderr: string): HermesCliResult {
-  const cleaned = cleanText(rawStdout);
-  const match = SESSION_ID_RE.exec(cleaned);
+  const cleanedStdout = cleanText(rawStdout);
+  const cleanedCombined = cleanText([rawStdout, rawStderr].filter(Boolean).join("\n"));
+  const match = SESSION_ID_RE.exec(cleanedStdout) ?? SESSION_ID_RE.exec(cleanedCombined);
 
   if (!match) {
-    const combined = [rawStdout, rawStderr].filter(Boolean).join("\n");
-    throw new Error(`hermes: missing session_id in output.\n${combined}`);
+    throw new Error(`hermes: missing session_id in output.\n${cleanedCombined}`);
   }
 
   const sessionId = match[1]!;
-  // Body is everything before the session_id line.
-  const sessionIdLineStart = cleaned.lastIndexOf("\nsession_id:");
-  const bodyRaw = sessionIdLineStart >= 0 ? cleaned.slice(0, sessionIdLineStart) : cleaned;
+  // Body is stdout before the session_id line. Recent Hermes builds can emit
+  // the session_id marker on stderr, so do not treat stderr as assistant text.
+  const sessionIdLineStart = cleanedStdout.lastIndexOf("\nsession_id:");
+  const bodyRaw = sessionIdLineStart >= 0 ? cleanedStdout.slice(0, sessionIdLineStart) : cleanedStdout;
   const body = stripChrome(bodyRaw);
 
   return { body, sessionId };

plugins/fusion-plugin-hermes-runtime/src/runtime-adapter.ts

@@ -51,10 +51,12 @@ export class HermesRuntimeAdapter implements AgentRuntime {
   }
 
   async createSession(options: AgentRuntimeOptions): Promise<AgentSessionResult> {
+    const messages: unknown[] = [];
     const session: HermesStreamSession = {
       model: undefined,
       systemPrompt: options.systemPrompt,
-      messages: [],
+      messages,
+      state: { messages },
       apiKey: undefined,
       thinkingLevel: undefined,
       sessionId: "",
@@ -82,12 +84,14 @@ export class HermesRuntimeAdapter implements AgentRuntime {
     const promptWithContext = resumeId
       ? prompt
       : `${session.fusedSystemPrompt}\n\nUser request:\n${prompt}`;
+    session.messages.push({ role: "user", content: prompt });
     const result = await invokeHermesCli(promptWithContext, this.settings, resumeId);
 
     session.sessionId = result.sessionId;
     session.lastModelDescription = this.describeFromSettings();
 
     if (result.body) {
+      session.messages.push({ role: "assistant", content: result.body });
       session.callbacks.onText?.(result.body);
     }
   }

plugins/fusion-plugin-hermes-runtime/src/types.ts

@@ -23,6 +23,10 @@ export interface HermesStreamSession {
   model: unknown;
   systemPrompt: string;
   messages: unknown[];
+  state: {
+    messages: unknown[];
+    errorMessage?: string;
+  };
   apiKey: string | undefined;
   thinkingLevel: string | undefined;
   sessionId: string;