feat: add dynamic tool loading system with Railway executor

Implements a complete dynamic tool loading system that allows the playground to discover and load tools from the TPMJS registry at runtime.

**Architecture:**
- Search tool package (@tpmjs/search-registry) - Searches registry for tools
- Search API endpoint (/api/tools/search) - Text-based search with scoring
- Pre-flight tool loading - Automatically searches and loads tools on every message
- Railway executor service (Deno) - Loads tools from esm.sh via HTTP imports
- Dynamic tool loader - Calls Railway to load and execute tools remotely

**Key Components:**

1. Railway Executor (apps/railway-executor/)
   - Deno-based service that natively supports HTTP imports
   - Endpoints: /load-and-describe, /execute-tool, /cache/stats, /cache/clear
   - Deploys to Railway with deno run --allow-net --allow-env server.ts

2. Search Tool Package (packages/tools/search-registry/)
   - AI SDK v6 tool for searching TPMJS registry
   - Uses jsonSchema + inputSchema pattern
   - Searches /api/tools/search endpoint

3. Search API (apps/web/src/app/api/tools/search/)
   - Text-based search with composite scoring
   - Scores: text relevance + quality boost + download boost
   - Returns tool metadata with importUrl for dynamic loading

4. Dynamic Tool Loader (apps/playground/src/lib/dynamic-tool-loader.ts)
   - Calls Railway service to load tools from esm.sh
   - Creates tool wrappers that execute remotely
   - Process-level module cache + per-conversation tracking

5. Pre-flight Loading (apps/playground/src/app/api/chat/route.ts)
   - Automatically searches for tools on every user message
   - Loads top 5 matching tools before agent processes request
   - Merges with static tools for seamless experience

**Technical Decisions:**
- Deno over Node.js: Native HTTP import support without flags
- Remote execution: Tools run in Railway sandbox, not Vercel
- Pre-flight loading: Better UX than two-turn search pattern
- Text search: BM25 had dependency issues, simple scoring works well

**Environment Variables:**
- RAILWAY_SERVICE_URL: https://endearing-commitment-production.up.railway.app

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

packages/tools/search-registry/.npmignore

@@ -0,0 +1,5 @@
+src/
+tsconfig.json
+*.test.ts
+*.spec.ts
+.turbo

packages/tools/search-registry/package.json

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+{
+  "name": "@tpmjs/search-registry",
+  "version": "0.1.0",
+  "description": "AI SDK tool for searching the TPMJS tool registry",
+  "main": "dist/index.js",
+  "types": "dist/index.d.ts",
+  "scripts": {
+    "build": "tsc",
+    "dev": "tsc --watch",
+    "type-check": "tsc --noEmit"
+  },
+  "keywords": ["tpmjs-tool", "ai", "search", "tool-registry"],
+  "dependencies": {
+    "ai": "6.0.0-beta.124",
+    "zod": "^3.23.0"
+  },
+  "devDependencies": {
+    "@tpmjs/tsconfig": "workspace:*",
+    "typescript": "^5.7.2"
+  },
+  "tpmjs": {
+    "category": "api-integration",
+    "frameworks": ["vercel-ai"],
+    "tools": [
+      {
+        "exportName": "searchTpmjsToolsTool",
+        "description": "Search the TPMJS tool registry to find AI SDK tools by keyword, category, or description. Returns tool metadata for dynamic loading.",
+        "parameters": [
+          {
+            "name": "query",
+            "type": "string",
+            "description": "Search query (keywords, tool names, descriptions)",
+            "required": true
+          },
+          {
+            "name": "category",
+            "type": "string",
+            "description": "Filter by category (optional)",
+            "required": false
+          },
+          {
+            "name": "limit",
+            "type": "number",
+            "description": "Maximum results (1-20, default 10)",
+            "required": false
+          }
+        ],
+        "returns": {
+          "type": "object",
+          "description": "Search results with tool metadata including packageName, exportName, version, importUrl"
+        },
+        "aiAgent": {
+          "useCase": "Use when you need a tool that isn't currently available. Search for tools by keyword or domain.",
+          "examples": [
+            "Search for 'weather' when asked about weather",
+            "Search for 'wikipedia' when asked to search Wikipedia",
+            "Search for 'database' when working with SQL"
+          ]
+        }
+      }
+    ]
+  }
+}

packages/tools/search-registry/src/index.ts

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+import { jsonSchema, tool } from 'ai';
+
+/**
+ * Input type for Search TPMJS Tools
+ */
+type SearchTpmjsToolsInput = {
+  query: string;
+  category?: string;
+  limit?: number;
+};
+
+/**
+ * AI SDK tool for searching the TPMJS tool registry
+ *
+ * This meta-tool enables agents to discover and load tools dynamically from the registry.
+ * When an agent needs a tool that isn't currently available, it can search for it by keyword,
+ * category, or description. The search results include all metadata needed to dynamically
+ * import the tool at runtime.
+ */
+export const searchTpmjsToolsTool = tool({
+  description:
+    "Search the TPMJS tool registry to find AI SDK tools. Use this when you need a tool that isn't currently available. Returns tool metadata including package names, export names, and import URLs.",
+  inputSchema: jsonSchema<SearchTpmjsToolsInput>({
+    type: 'object',
+    properties: {
+      query: {
+        type: 'string',
+        description: 'Search query (keywords, tool names, descriptions)',
+      },
+      category: {
+        type: 'string',
+        description: 'Filter by tool category (optional)',
+        enum: [
+          'web-scraping',
+          'data-processing',
+          'file-operations',
+          'communication',
+          'database',
+          'api-integration',
+          'image-processing',
+          'text-analysis',
+          'automation',
+          'ai-ml',
+          'security',
+          'monitoring',
+        ],
+      },
+      limit: {
+        type: 'number',
+        description: 'Maximum number of results (1-20, default 10)',
+        minimum: 1,
+        maximum: 20,
+      },
+    },
+    required: ['query'],
+    additionalProperties: false,
+  }),
+  async execute({ query, category, limit = 10 }) {
+    console.log('🔍 searchTpmjsTools.execute() called with:', { query, category, limit });
+
+    const params = new URLSearchParams({
+      q: query,
+      limit: String(limit),
+      ...(category && { category }),
+    });
+
+    // Use environment variable or default to localhost for development
+    const baseUrl = process.env.TPMJS_API_URL || 'http://localhost:3000';
+    const url = `${baseUrl}/api/tools/search?${params}`;
+
+    console.log(`🌐 Fetching: ${url}`);
+
+    const response = await fetch(url);
+
+    console.log(`📡 Response status: ${response.status} ${response.statusText}`);
+
+    if (!response.ok) {
+      throw new Error(`Search failed: ${response.statusText}`);
+    }
+
+    const data = (await response.json()) as any;
+    console.log('📦 Search response data:', JSON.stringify(data, null, 2));
+
+    return {
+      query,
+      matchCount: data.results?.total || data.data?.length || 0,
+      tools: (data.results?.tools || data.data || []).map((tool: any) => ({
+        toolId: tool.id,
+        packageName: tool.package.npmPackageName,
+        exportName: tool.exportName,
+        description: tool.description,
+        category: tool.package.category,
+        qualityScore: tool.qualityScore,
+        frameworks: tool.package.frameworks,
+        env: tool.package.env,
+        version: tool.package.npmVersion,
+        importUrl: `https://esm.sh/${tool.package.npmPackageName}@${tool.package.npmVersion}`,
+      })),
+    };
+  },
+});

packages/tools/search-registry/tsconfig.json

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+{
+  "extends": "@tpmjs/tsconfig/base.json",
+  "compilerOptions": {
+    "outDir": "./dist",
+    "rootDir": "./src",
+    "declaration": true,
+    "declarationMap": true,
+    "sourceMap": true
+  },
+  "include": ["src/**/*"],
+  "exclude": ["node_modules", "dist"]
+}