feat: persistent session UUID in agent.json

- session_id auto-generated on first run, saved to agent.json
- Survives agent renames (slug changes don't break session history)
- Directory mode: agent works inside its folder (agentHome = workspace)

src/config.ts

@@ -1,6 +1,7 @@
 import path from 'path';
 import os from 'os';
 import fs from 'fs';
+import crypto from 'crypto';
 
 export interface Config {
   port: number;
@@ -33,6 +34,8 @@ export interface AgentConfig {
   heartbeatIntervalSec: number;
   /** Restrict file access to these directories. Empty = unrestricted. */
   allowedPaths: string[];
+  /** Persistent session UUID — survives renames. Stored in agent.json. */
+  sessionId: string;
 }
 
 const homeDir = os.homedir();
@@ -159,5 +162,30 @@ export function loadAgentConfig(): AgentConfig {
     apiKey: process.env.PICOGENT_API_KEY || process.env.ANTHROPIC_API_KEY || (file.api_key as string) || '',
     heartbeatIntervalSec: (file.heartbeat_interval_sec as number) || 30,
     allowedPaths: (file.allowed_paths as string[]) || [],
+    sessionId: ensureSessionId(file, configPath),
   };
 }
+
+/**
+ * Ensure agent.json has a persistent session_id.
+ * Generates UUID on first run and writes it back to the config file.
+ */
+function ensureSessionId(file: Record<string, unknown>, configPath: string | null): string {
+  if (file.session_id && typeof file.session_id === 'string') {
+    return file.session_id;
+  }
+
+  const id = crypto.randomUUID();
+
+  // Persist to agent.json if we have a path
+  if (configPath) {
+    try {
+      file.session_id = id;
+      fs.writeFileSync(configPath, JSON.stringify(file, null, 2) + '\n');
+    } catch {
+      // Non-fatal — session works in memory
+    }
+  }
+
+  return id;
+}

src/router.ts

@@ -24,7 +24,7 @@ export class EventRouter {
     private client: TrackerClient,
     private taskTracker: TaskTracker,
   ) {
-    this.sessionId = `agent-${config.slug}`;
+    this.sessionId = config.sessionId;
     this.trackerTools = createTrackerTools({
       trackerClient: client,
       agentSlug: config.slug,