Claude Code TestLens testlens_mutate
How to: Claude Code TestLens testlens_mutate
Add TestLens to Claude Code
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01
Run this in your project directory.
claude mcp add --transport http testlens https://testlens.bigfloppy.net/mcp-
02
Restart your session so the server is picked up.
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03
Ask for something testlens_mutate does. Claude Code lists the server's tools on connect and calls testlens_mutate itself — you do not invoke it by name.
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04
If nothing happens, check the server is running and that TestLens's identifier in your config matches the one above exactly.
Adds it for this project only. Append --scope user to make it available everywhere. Claude Code docs
Same tool, other clients
This list was read from the server itself, by connecting to it and calling tools/list on 14 November 2026. It is what
the server actually exposes, not what its listing claims.
Mutating and Read-only are read off each tool's name, not its schema — a hint, not a guarantee. The registry stores tool names only; connect the server for its live schemas.