feat(agent): skill invocation — load and execute skills from catalog (#128) (#143)

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

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

@@ -14,6 +14,7 @@ import { EmbeddingService } from '../memory/embedding.service.js';
 import { CoordService } from '../coord/coord.service.js';
 import { ProviderService } from './provider.service.js';
 import { McpClientService } from '../mcp-client/mcp-client.service.js';
+import { SkillLoaderService } from './skill-loader.service.js';
 import { createBrainTools } from './tools/brain-tools.js';
 import { createCoordTools } from './tools/coord-tools.js';
 import { createMemoryTools } from './tools/memory-tools.js';
@@ -38,6 +39,8 @@ export interface AgentSession {
   createdAt: number;
   promptCount: number;
   channels: Set<string>;
+  /** System prompt additions injected from enabled prompt-type skills. */
+  skillPromptAdditions: string[];
 }
 
 @Injectable()
@@ -55,6 +58,7 @@ export class AgentService implements OnModuleDestroy {
     @Inject(EmbeddingService) private readonly embeddingService: EmbeddingService,
     @Inject(CoordService) private readonly coordService: CoordService,
     @Inject(McpClientService) private readonly mcpClientService: McpClientService,
+    @Inject(SkillLoaderService) private readonly skillLoaderService: SkillLoaderService,
   ) {
     const fileBaseDir = process.env['AGENT_FILE_SANDBOX_DIR'] ?? process.cwd();
     const gitDefaultCwd = process.env['AGENT_GIT_CWD'] ?? process.cwd();
@@ -98,9 +102,21 @@ export class AgentService implements OnModuleDestroy {
       `Creating agent session: ${sessionId} (provider=${providerName}, model=${modelId})`,
     );
 
+    // Load skill tools from the catalog
+    const { metaTools: skillMetaTools, promptAdditions } =
+      await this.skillLoaderService.loadForSession();
+    if (skillMetaTools.length > 0) {
+      this.logger.log(`Attaching ${skillMetaTools.length} skill tool(s) to session ${sessionId}`);
+    }
+    if (promptAdditions.length > 0) {
+      this.logger.log(
+        `Injecting ${promptAdditions.length} skill prompt addition(s) into session ${sessionId}`,
+      );
+    }
+
     // Combine static tools with dynamically discovered MCP client tools
     const mcpTools = this.mcpClientService.getToolDefinitions();
-    const allCustomTools = [...this.customTools, ...mcpTools];
+    const allCustomTools = [...this.customTools, ...skillMetaTools, ...mcpTools];
     if (mcpTools.length > 0) {
       this.logger.log(`Attaching ${mcpTools.length} MCP client tool(s) to session ${sessionId}`);
     }
@@ -145,6 +161,7 @@ export class AgentService implements OnModuleDestroy {
       createdAt: Date.now(),
       promptCount: 0,
       channels: new Set(),
+      skillPromptAdditions: promptAdditions,
     };
 
     this.sessions.set(sessionId, session);