builtwith-api: Instructions file for Claude Code

CLAUDE.md — builtwith-api

Project overview

Bun workspace monorepo for the BuiltWith API suite. Two npm packages:

• builtwith-api — TypeScript SDK + CLI. All 13 API endpoints. Depends only on zod.
• builtwith-mcp — MCP server for Claude Desktop, Cursor, etc. Depends on builtwith-api + @modelcontextprotocol/sdk.

Tech stack

• Runtime: Bun (build, test, compile, workspaces)
• Language: TypeScript (strict mode, ESM-only)
• Validation: Zod v4 (zod/v4 import path)
• Linting: Biome
• Docs: VitePress + TypeDoc

Key conventions

• Schemas are the source of truth — all types are inferred from Zod schemas via z.infer<>. Never duplicate types manually.
• Response schemas use z.strictObject() — this catches upstream API drift. If BuiltWith adds new fields, the schema parse will fail, signaling that the schema needs updating.
• Input schemas also use z.strictObject() — prevents typos in option names from being silently ignored.
• Dual request functions — request() for strict JSON parsing, requestSafe() for endpoints (lists, trends) that occasionally return malformed JSON.
• Commands registry — packages/builtwith-api/src/commands.ts defines all 13 commands once; both CLI and MCP consume the same definitions.
• Minimal dependencies — builtwith-api depends only on zod. builtwith-mcp adds @modelcontextprotocol/sdk.

Commands

bun run build       # Build all packages
bun run test        # Test all packages
bun run lint        # Biome check
bun run lint:fix    # Biome auto-fix
bun run docs:dev    # Local docs dev server

File structure

packages/
  builtwith-api/
    src/
      index.ts      — createClient() factory, all 13 API methods
      schemas.ts    — Zod schemas for inputs + responses, BuiltWithClient interface
      commands.ts   — Command registry shared by CLI and MCP
      params.ts     — URL building, query string, boolean flag mapping
      request.ts    — HTTP request, API error detection + Zod validation
      errors.ts     — Error formatting (Zod + generic)
      config.ts     — Constants (response format enum)
      cli.ts        — CLI entry point
      format.ts     — Table formatter for --table CLI output
    test/
      *.test.ts     — Unit + integration tests (Bun test runner)
  builtwith-mcp/
    src/
      mcp.ts        — MCP server entry point
    test/
      mcp.test.ts   — MCP server tests
docs/                 — VitePress docs site (deployed to builtwith.zach.dev)