# Toolweather

> Toolweather tells AI agents whether an MCP server or tool is safe to call right now, and suggests working alternatives. It checks ~2,000 remote MCP servers from the official MCP registry every 15 minutes (handshake, auth, latency, tool lists, breaking tool changes, 2026-07-28 spec readiness). Checks are read-only: tools are never called.

Free tier: 1,000 calls per API key per day. Get a key by emailing toolweather@mail.grokbot.com.

## Use it

- [MCP endpoint (streamable HTTP)](https://toolweather.toolweather.workers.dev/mcp): tools `is_safe_to_call(server, tool?)`, `suggest_alternatives(query, limit?)`, `watch_server(server, webhook_url)`, `list_watches()`, `unwatch_server(id)`. Send header `X-API-Key: <key>`. Answers 2026-07-28 `server/discover` and legacy `initialize`.
- [REST: is_safe_to_call](https://toolweather.toolweather.workers.dev/v1/is_safe_to_call?server=io.github.owner/name): returns `verdict` (safe / caution / unsafe / unknown), reasons, status, latency, auth info, last tool change, `last_checked`.
- [REST: suggest_alternatives](https://toolweather.toolweather.workers.dev/v1/suggest_alternatives?q=send%20email): working servers with similar tools.
- REST: change alerts. `POST /v1/watches {"server","webhook_url"}`, `GET /v1/watches`, `DELETE /v1/watches/{id}`. Toolweather POSTs JSON to your https webhook when a watched server's verdict changes, it starts requiring auth, or its tool list has a breaking change (checked every 5 minutes against 15-minute probes). Verify `X-Toolweather-Signature: t=<unix>,v1=<hex HMAC-SHA256(secret, "<t>.<raw body>")>` with the secret returned at creation. Free tier: 3 watches per key.
- [OpenAPI 3.1 spec](https://toolweather.toolweather.workers.dev/openapi.json)
- [MCP server card](https://toolweather.toolweather.workers.dev/.well-known/mcp)

Note: requests with Python's default `Python-urllib` User-Agent are rejected by Cloudflare's edge (error 1010). Set any descriptive User-Agent header.

## Docs

- [README and install snippets (Claude Desktop, Cursor, VS Code)](https://github.com/toolweather/toolweather#install)
- [Live status page](https://toolweather.pages.dev)
- [Official MCP registry entry](https://registry.modelcontextprotocol.io/v0.1/servers/io.github.toolweather%2Ftoolweather/versions/latest): `io.github.toolweather/toolweather`

## Optional

- [Probing policy](https://github.com/toolweather/toolweather#probing-policy-read-only): read-only, at most one request per host in flight, opt-out by email.