Toolweather

Know when an MCP server you trust changes its tools or auth after you approved it.

You check an MCP server once and add it to your agent. Later its tools change, or it starts asking for sign-in, and nobody tells you. Toolweather already checks the remote servers in the official MCP registry about every 15 minutes. This plan would send you an email when one you picked changes.

What Toolweather detects today

Each check runs the MCP initialize handshake and tools/list, without credentials, and compares the result with the previous check.

• A tool is removed. breaking
• A tool gets a new required parameter, loses a parameter, or a parameter changes type. breaking
• A tool is added, its description changes, or its input or output schema changes in another way. recorded
• The server starts answering with HTTP 401 or 403, so it now requires sign-in.
• The server stops answering or comes back.

What the plan would add

• Email alerts. Today alerts go only to a webhook you run, and a free key can watch 3 servers.
• Alerts on every change in the list above, including new tools and changed descriptions. Today those are recorded but not alerted.
• More than 3 watched servers.

What it can't see

• Local (stdio) servers, and remote servers that aren't in the official MCP registry.
• Tools behind sign-in. For a server that requires auth, we see that it does, not the tools you get after signing in.
• A change that is made and undone between two checks.

Need it now? The free Toolweather MCP server has a watch_server tool that sends a signed webhook when a watched server goes down, starts requiring auth, or has a breaking tool change.