feat: tool registration — brain tools for agent sessions (P2-004) (#76)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

apps/gateway/src/agent/agent.service.ts

@@ -1,11 +1,15 @@
-import { Injectable, Logger, type OnModuleDestroy } from '@nestjs/common';
+import { Inject, Injectable, Logger, type OnModuleDestroy } from '@nestjs/common';
 import {
   createAgentSession,
   SessionManager,
   type AgentSession as PiAgentSession,
   type AgentSessionEvent,
+  type ToolDefinition,
 } from '@mariozechner/pi-coding-agent';
+import type { Brain } from '@mosaic/brain';
+import { BRAIN } from '../brain/brain.tokens.js';
 import { ProviderService } from './provider.service.js';
+import { createBrainTools } from './tools/brain-tools.js';
 
 export interface AgentSessionOptions {
   provider?: string;
@@ -27,7 +31,15 @@ export class AgentService implements OnModuleDestroy {
   private readonly sessions = new Map<string, AgentSession>();
   private readonly creating = new Map<string, Promise<AgentSession>>();
 
-  constructor(private readonly providerService: ProviderService) {}
+  private readonly customTools: ToolDefinition[];
+
+  constructor(
+    private readonly providerService: ProviderService,
+    @Inject(BRAIN) private readonly brain: Brain,
+  ) {
+    this.customTools = createBrainTools(brain);
+    this.logger.log(`Registered ${this.customTools.length} custom tools`);
+  }
 
   async createSession(sessionId: string, options?: AgentSessionOptions): Promise<AgentSession> {
     const existing = this.sessions.get(sessionId);
@@ -62,6 +74,7 @@ export class AgentService implements OnModuleDestroy {
         modelRegistry: this.providerService.getRegistry(),
         model: model ?? undefined,
         tools: [],
+        customTools: this.customTools,
       });
       piSession = result.session;
     } catch (err) {