customclaw-mcp

Install, don't regenerate. MCP server for the CustomClaw registry — 37 vetted single-file utilities for LLM and agent code (rate limiters that respect Retry-After, JSON repair, response caches, retry with backoff, token counters, PII scrubbers). Your agent gets four native tool calls instead of 120 lines of plausible-looking new code.

📖 Background: The utility-amnesia problem — why your coding agent rewrote the same rate limiter 47 times.

30-second install

npx -y customclaw-mcp

Drop that command into your MCP client's config (snippets below) and you're done. Free tools install with no auth.

What it does

Plugs the CustomClaw catalog (37 utilities, 32 free) into any Model Context Protocol host — Claude Desktop, Claude Code, Cursor, Windsurf, anything that speaks MCP — as four tools:

Tool	Arguments	Purpose
list_utilities	—	Full catalog (cached 5 min)
search_utilities	query: string	Fuzzy match on slug/name/description
get_utility_info	slug: string	Full detail for one utility
install_utility	slug, target_dir, session_id?	Fetch payload + write files

Install (by client)

Claude Desktop

~/Library/Application Support/Claude/claude_desktop_config.json (macOS) or %APPDATA%\Claude\claude_desktop_config.json (Windows):

{
  "mcpServers": {
    "customclaw": {
      "command": "npx",
      "args": ["-y", "customclaw-mcp"]
    }
  }
}

Restart Claude Desktop. Tools appear in the tool picker.

Claude Code

claude mcp add customclaw -- npx -y customclaw-mcp

Cursor / Windsurf / any stdio MCP host

Point the host at npx -y customclaw-mcp.

Streamable HTTP (smithery, ChatGPT, etc.)

Use the hosted endpoint: https://customclaw.company/mcp. Registered on smithery as onlythebestswfl/customclaw.

Example prompts

Once connected:

• "Add a rate limiter that respects Retry-After." → search_utilities → install_utility rate-limit-handler
• "I need to parse broken JSON from Claude output." → json-repair
• "What do you have for caching LLM responses?" → search_utilities → short results table
• "Install token-optimiser into ./src/lib." → direct install_utility
• "Scan this project's prompts for injection — is there a tool?" → injection-scanner

Task → slug quick reference

If you need…	Slug
Rate limiting with Retry-After handling	rate-limit-handler
JSON repair for LLM output	json-repair
Response cache by prompt hash	response-cache
Retry with exponential backoff	retry-with-backoff
Token counting across models	token-optimiser
PII scrubbing before logging	pii-scrubber
Prompt-injection scanner	injection-scanner
Cost forecaster per provider	cost-forecaster

Full list via list_utilities or customclaw.company/api/catalog.

Paid utilities

For paid utilities, pass the Stripe checkout session_id from your receipt email as the session_id argument to install_utility. Without it, the tool returns a helpful 401.

Environment

• CUSTOMCLAW_BASE — registry base URL override (default https://customclaw.company). Useful for staging or self-hosted mirrors.

How it works

• Node.js stdio MCP server. Dependency: @modelcontextprotocol/sdk.
• Catalog fetched from GET /api/catalog; cached 5 min per process.
• Payloads from GET /api/cli?slug=<slug>[&session_id=<cs_...>] — same endpoint the official customclaw-cli uses.
• install_utility refuses to write outside target_dir (path-traversal guard).

Links

• Registry: customclaw.company
• CLI companion: customclaw-cli
• Source: github.com/onlythebestswfl-ops/customclaw-mcp

License

MIT.