feat(#66): implement tag filtering in search API endpoint

Add support for filtering search results by tags in the main search endpoint.

Changes:
- Add tags parameter to SearchQueryDto (comma-separated tag slugs)
- Implement tag filtering in SearchService.search() method
- Update SQL query to join with knowledge_entry_tags when tags provided
- Entries must have ALL specified tags (AND logic)
- Add tests for tag filtering (2 controller tests, 2 service tests)
- Update endpoint documentation
- Fix non-null assertion linting error

The search endpoint now supports:
- Full-text search with ranking (ts_rank)
- Snippet generation with highlighting (ts_headline)
- Status filtering
- Tag filtering (new)
- Pagination

Example: GET /api/knowledge/search?q=api&tags=documentation,tutorial

All tests pass (25 total), type checking passes, linting passes.

Fixes #66

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

apps/orchestrator/src/spawner/agent-spawner.service.spec.ts

@@ -0,0 +1,255 @@
+import { ConfigService } from "@nestjs/config";
+import { describe, it, expect, beforeEach, vi } from "vitest";
+import { AgentSpawnerService } from "./agent-spawner.service";
+import { SpawnAgentRequest } from "./types/agent-spawner.types";
+
+describe("AgentSpawnerService", () => {
+  let service: AgentSpawnerService;
+  let mockConfigService: ConfigService;
+
+  beforeEach(() => {
+    // Create mock ConfigService
+    mockConfigService = {
+      get: vi.fn((key: string) => {
+        if (key === "orchestrator.claude.apiKey") {
+          return "test-api-key";
+        }
+        return undefined;
+      }),
+    } as any;
+
+    // Create service with mock
+    service = new AgentSpawnerService(mockConfigService);
+  });
+
+  describe("constructor", () => {
+    it("should be defined", () => {
+      expect(service).toBeDefined();
+    });
+
+    it("should initialize with Claude API key from config", () => {
+      expect(mockConfigService.get).toHaveBeenCalledWith("orchestrator.claude.apiKey");
+    });
+
+    it("should throw error if Claude API key is missing", () => {
+      const badConfigService = {
+        get: vi.fn(() => undefined),
+      } as any;
+
+      expect(() => new AgentSpawnerService(badConfigService)).toThrow(
+        "CLAUDE_API_KEY is not configured"
+      );
+    });
+  });
+
+  describe("spawnAgent", () => {
+    const validRequest: SpawnAgentRequest = {
+      taskId: "task-123",
+      agentType: "worker",
+      context: {
+        repository: "https://github.com/test/repo.git",
+        branch: "main",
+        workItems: ["Implement feature X"],
+      },
+    };
+
+    it("should spawn an agent and return agentId", () => {
+      const response = service.spawnAgent(validRequest);
+
+      expect(response).toBeDefined();
+      expect(response.agentId).toBeDefined();
+      expect(typeof response.agentId).toBe("string");
+      expect(response.state).toBe("spawning");
+      expect(response.spawnedAt).toBeInstanceOf(Date);
+    });
+
+    it("should generate unique agentId for each spawn", () => {
+      const response1 = service.spawnAgent(validRequest);
+      const response2 = service.spawnAgent(validRequest);
+
+      expect(response1.agentId).not.toBe(response2.agentId);
+    });
+
+    it("should track agent session", () => {
+      const response = service.spawnAgent(validRequest);
+      const session = service.getAgentSession(response.agentId);
+
+      expect(session).toBeDefined();
+      expect(session?.agentId).toBe(response.agentId);
+      expect(session?.taskId).toBe(validRequest.taskId);
+      expect(session?.agentType).toBe(validRequest.agentType);
+      expect(session?.state).toBe("spawning");
+    });
+
+    it("should validate taskId is provided", () => {
+      const invalidRequest = {
+        ...validRequest,
+        taskId: "",
+      };
+
+      expect(() => service.spawnAgent(invalidRequest)).toThrow("taskId is required");
+    });
+
+    it("should validate agentType is valid", () => {
+      const invalidRequest = {
+        ...validRequest,
+        agentType: "invalid" as any,
+      };
+
+      expect(() => service.spawnAgent(invalidRequest)).toThrow(
+        "agentType must be one of: worker, reviewer, tester"
+      );
+    });
+
+    it("should validate context.repository is provided", () => {
+      const invalidRequest = {
+        ...validRequest,
+        context: {
+          ...validRequest.context,
+          repository: "",
+        },
+      };
+
+      expect(() => service.spawnAgent(invalidRequest)).toThrow("context.repository is required");
+    });
+
+    it("should validate context.branch is provided", () => {
+      const invalidRequest = {
+        ...validRequest,
+        context: {
+          ...validRequest.context,
+          branch: "",
+        },
+      };
+
+      expect(() => service.spawnAgent(invalidRequest)).toThrow("context.branch is required");
+    });
+
+    it("should validate context.workItems is not empty", () => {
+      const invalidRequest = {
+        ...validRequest,
+        context: {
+          ...validRequest.context,
+          workItems: [],
+        },
+      };
+
+      expect(() => service.spawnAgent(invalidRequest)).toThrow(
+        "context.workItems must not be empty"
+      );
+    });
+
+    it("should accept optional skills in context", () => {
+      const requestWithSkills: SpawnAgentRequest = {
+        ...validRequest,
+        context: {
+          ...validRequest.context,
+          skills: ["typescript", "nestjs"],
+        },
+      };
+
+      const response = service.spawnAgent(requestWithSkills);
+      const session = service.getAgentSession(response.agentId);
+
+      expect(session?.context.skills).toEqual(["typescript", "nestjs"]);
+    });
+
+    it("should accept optional options", () => {
+      const requestWithOptions: SpawnAgentRequest = {
+        ...validRequest,
+        options: {
+          sandbox: true,
+          timeout: 3600000,
+          maxRetries: 3,
+        },
+      };
+
+      const response = service.spawnAgent(requestWithOptions);
+      const session = service.getAgentSession(response.agentId);
+
+      expect(session?.options).toEqual({
+        sandbox: true,
+        timeout: 3600000,
+        maxRetries: 3,
+      });
+    });
+
+    it("should handle spawn errors gracefully", () => {
+      // Mock Claude SDK to throw error
+      const errorRequest = {
+        ...validRequest,
+        context: {
+          ...validRequest.context,
+          repository: "invalid-repo-that-will-fail",
+        },
+      };
+
+      // For now, this should not throw but handle gracefully
+      // We'll implement error handling in the service
+      const response = service.spawnAgent(errorRequest);
+      expect(response.agentId).toBeDefined();
+    });
+  });
+
+  describe("getAgentSession", () => {
+    it("should return undefined for non-existent agentId", () => {
+      const session = service.getAgentSession("non-existent-id");
+      expect(session).toBeUndefined();
+    });
+
+    it("should return session for existing agentId", () => {
+      const request: SpawnAgentRequest = {
+        taskId: "task-123",
+        agentType: "worker",
+        context: {
+          repository: "https://github.com/test/repo.git",
+          branch: "main",
+          workItems: ["Implement feature X"],
+        },
+      };
+
+      const response = service.spawnAgent(request);
+      const session = service.getAgentSession(response.agentId);
+
+      expect(session).toBeDefined();
+      expect(session?.agentId).toBe(response.agentId);
+    });
+  });
+
+  describe("listAgentSessions", () => {
+    it("should return empty array when no agents spawned", () => {
+      const sessions = service.listAgentSessions();
+      expect(sessions).toEqual([]);
+    });
+
+    it("should return all spawned agent sessions", () => {
+      const request1: SpawnAgentRequest = {
+        taskId: "task-1",
+        agentType: "worker",
+        context: {
+          repository: "https://github.com/test/repo1.git",
+          branch: "main",
+          workItems: ["Task 1"],
+        },
+      };
+
+      const request2: SpawnAgentRequest = {
+        taskId: "task-2",
+        agentType: "reviewer",
+        context: {
+          repository: "https://github.com/test/repo2.git",
+          branch: "develop",
+          workItems: ["Task 2"],
+        },
+      };
+
+      service.spawnAgent(request1);
+      service.spawnAgent(request2);
+
+      const sessions = service.listAgentSessions();
+      expect(sessions).toHaveLength(2);
+      expect(sessions[0].agentType).toBe("worker");
+      expect(sessions[1].agentType).toBe("reviewer");
+    });
+  });
+});

apps/orchestrator/src/spawner/agent-spawner.service.ts

@@ -0,0 +1,120 @@
+import { Injectable, Logger } from "@nestjs/common";
+import { ConfigService } from "@nestjs/config";
+import Anthropic from "@anthropic-ai/sdk";
+import { randomUUID } from "crypto";
+import {
+  SpawnAgentRequest,
+  SpawnAgentResponse,
+  AgentSession,
+  AgentType,
+} from "./types/agent-spawner.types";
+
+/**
+ * Service responsible for spawning Claude agents using Anthropic SDK
+ */
+@Injectable()
+export class AgentSpawnerService {
+  private readonly logger = new Logger(AgentSpawnerService.name);
+  private readonly anthropic: Anthropic;
+  private readonly sessions = new Map<string, AgentSession>();
+
+  constructor(private readonly configService: ConfigService) {
+    const apiKey = this.configService.get<string>("orchestrator.claude.apiKey");
+
+    if (!apiKey) {
+      throw new Error("CLAUDE_API_KEY is not configured");
+    }
+
+    this.anthropic = new Anthropic({
+      apiKey,
+    });
+
+    this.logger.log("AgentSpawnerService initialized with Claude SDK");
+  }
+
+  /**
+   * Spawn a new agent with the given configuration
+   * @param request Agent spawn request
+   * @returns Agent spawn response with agentId
+   */
+  spawnAgent(request: SpawnAgentRequest): SpawnAgentResponse {
+    this.logger.log(`Spawning agent for task: ${request.taskId}`);
+
+    // Validate request
+    this.validateSpawnRequest(request);
+
+    // Generate unique agent ID
+    const agentId = randomUUID();
+    const spawnedAt = new Date();
+
+    // Create agent session
+    const session: AgentSession = {
+      agentId,
+      taskId: request.taskId,
+      agentType: request.agentType,
+      state: "spawning",
+      context: request.context,
+      options: request.options,
+      spawnedAt,
+    };
+
+    // Store session
+    this.sessions.set(agentId, session);
+
+    this.logger.log(`Agent spawned successfully: ${agentId} (type: ${request.agentType})`);
+
+    // TODO: Actual Claude SDK integration will be implemented in next iteration
+    // For now, we're just creating the session and tracking it
+
+    return {
+      agentId,
+      state: "spawning",
+      spawnedAt,
+    };
+  }
+
+  /**
+   * Get agent session by agentId
+   * @param agentId Unique agent identifier
+   * @returns Agent session or undefined if not found
+   */
+  getAgentSession(agentId: string): AgentSession | undefined {
+    return this.sessions.get(agentId);
+  }
+
+  /**
+   * List all agent sessions
+   * @returns Array of all agent sessions
+   */
+  listAgentSessions(): AgentSession[] {
+    return Array.from(this.sessions.values());
+  }
+
+  /**
+   * Validate spawn agent request
+   * @param request Spawn request to validate
+   * @throws Error if validation fails
+   */
+  private validateSpawnRequest(request: SpawnAgentRequest): void {
+    if (!request.taskId || request.taskId.trim() === "") {
+      throw new Error("taskId is required");
+    }
+
+    const validAgentTypes: AgentType[] = ["worker", "reviewer", "tester"];
+    if (!validAgentTypes.includes(request.agentType)) {
+      throw new Error(`agentType must be one of: ${validAgentTypes.join(", ")}`);
+    }
+
+    if (!request.context.repository || request.context.repository.trim() === "") {
+      throw new Error("context.repository is required");
+    }
+
+    if (!request.context.branch || request.context.branch.trim() === "") {
+      throw new Error("context.branch is required");
+    }
+
+    if (request.context.workItems.length === 0) {
+      throw new Error("context.workItems must not be empty");
+    }
+  }
+}

apps/orchestrator/src/spawner/index.ts

@@ -0,0 +1,6 @@
+/**
+ * Spawner module exports
+ */
+export { AgentSpawnerService } from "./agent-spawner.service";
+export { SpawnerModule } from "./spawner.module";
+export * from "./types/agent-spawner.types";

apps/orchestrator/src/spawner/spawner.module.ts

@@ -1,4 +1,8 @@
 import { Module } from "@nestjs/common";
+import { AgentSpawnerService } from "./agent-spawner.service";
 
-@Module({})
+@Module({
+  providers: [AgentSpawnerService],
+  exports: [AgentSpawnerService],
+})
 export class SpawnerModule {}

apps/orchestrator/src/spawner/types/agent-spawner.types.ts

@@ -0,0 +1,85 @@
+/**
+ * Agent type definitions for spawning
+ */
+export type AgentType = "worker" | "reviewer" | "tester";
+
+/**
+ * Agent lifecycle states
+ */
+export type AgentState = "spawning" | "running" | "completed" | "failed" | "killed";
+
+/**
+ * Context provided to the agent for task execution
+ */
+export interface AgentContext {
+  /** Git repository URL or path */
+  repository: string;
+  /** Git branch to work on */
+  branch: string;
+  /** Work items for the agent to complete */
+  workItems: string[];
+  /** Optional skills to load */
+  skills?: string[];
+}
+
+/**
+ * Options for spawning an agent
+ */
+export interface SpawnAgentOptions {
+  /** Enable Docker sandbox isolation */
+  sandbox?: boolean;
+  /** Timeout in milliseconds */
+  timeout?: number;
+  /** Maximum retry attempts */
+  maxRetries?: number;
+}
+
+/**
+ * Request payload for spawning an agent
+ */
+export interface SpawnAgentRequest {
+  /** Unique task identifier */
+  taskId: string;
+  /** Type of agent to spawn */
+  agentType: AgentType;
+  /** Context for task execution */
+  context: AgentContext;
+  /** Optional configuration */
+  options?: SpawnAgentOptions;
+}
+
+/**
+ * Response from spawning an agent
+ */
+export interface SpawnAgentResponse {
+  /** Unique agent identifier */
+  agentId: string;
+  /** Current agent state */
+  state: AgentState;
+  /** Timestamp when agent was spawned */
+  spawnedAt: Date;
+}
+
+/**
+ * Agent session metadata
+ */
+export interface AgentSession {
+  /** Unique agent identifier */
+  agentId: string;
+  /** Task identifier */
+  taskId: string;
+  /** Agent type */
+  agentType: AgentType;
+  /** Current state */
+  state: AgentState;
+  /** Context */
+  context: AgentContext;
+  /** Options */
+  options?: SpawnAgentOptions;
+  /** Spawn timestamp */
+  spawnedAt: Date;
+  /** Completion timestamp */
+  completedAt?: Date;
+  /** Error if failed */
+  error?: string;
+}