builtwith-api CLAUDE.md

builtwith-api CLAUDE.md is an instructions file for coding agents from zcaceres/builtwith-api. It costs 713 tokens per session, scanned A, original, MIT.

Project instructions for BuiltWith API, a Bun workspace monorepo containing a TypeScript SDK, command-line tool, and MCP server. A monorepo is one repository that contains multiple related packages.

In plain words
What is it for?
Use them when developing, testing, documenting, or extending either BuiltWith package, especially its Zod schemas, API requests, commands, or MCP integration.
Why use it?
They describe the project structure and conventions that keep its request handling, validation, types, and documentation consistent. They also explain how schemas detect unexpected changes in the upstream API.

Instructions file

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/zcaceres/builtwith-api/claude-md
Clone the repo
git clone --depth 1 https://github.com/zcaceres/builtwith-api

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for builtwith-api CLAUDE.md

README.md
[![agentmods](https://agentmods.dev/badge/instructions/zcaceres/builtwith-api/claude-md.svg)](https://agentmods.dev/instructions/zcaceres/builtwith-api/claude-md)
Your own site
<a href="https://agentmods.dev/instructions/zcaceres/builtwith-api/claude-md"><img src="https://agentmods.dev/badge/instructions/zcaceres/builtwith-api/claude-md.svg" alt="Measured on agentmods" height="20"></a>
Per session 713 This file is loaded in full into every session.
When invoked 713 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00713 $0.00713
Opus 5 $0.00357 $0.00357
Sonnet 5 $0.00143 $0.00143
Haiku 4.5 $0.00071 $0.00071

Measured 4d ago against content hash b22b02d7fd42, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

builtwith-api CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 4d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

CLAUDE.md · 67 lines

How it starts

The opening of the file, as written. The whole thing — 67 lines — stays where its author put it; the contents beside it link to each section on GitHub.

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 functionsrequest() for strict JSON parsing, requestSafe() for endpoints (lists, trends) that occasionally return malformed JSON.
  • Commands registrypackages/builtwith-api/src/commands.ts defines all 13 commands once; both CLI and MCP consume the same definitions.
  • Minimal dependenciesbuiltwith-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)

Read the full file on GitHub · 67 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 4d ago First seen · 67 lines · 713 tokens per session scan A b22b02d7fd42

Subscribe to this mod's changes

builtwith-api CLAUDE.md is an instructions file published in the GitHub repository zcaceres/builtwith-api (22 stars, last pushed 1mo ago), licensed MIT. It adds 713 tokens to every session, about $0.0036 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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