What it is
Five always-on utilities, plus two host-probing tools that stay unregistered until you enable them: cryptographic digests and constant-time comparison, CSPRNG identifiers, QR encoding, base64/hex/URL transcoding, and IP geolocation with the SSRF checks done properly.
Requirements
Bun 1.3.0 or newer, or Node.js 24 and above. No API key: the five always-on tools work immediately and geolocation defaults to the keyless ip-api tier, cached and capped at 45 requests a minute to match that tier's limit. A public hosted instance exists at https://toolkit.caseyjhand.com/mcp over Streamable HTTP if you would rather not run one. Locally it speaks stdio, or HTTP bound to 127.0.0.1 on port 3010 at /mcp with authentication selectable as none, jwt or oauth. The two host-probing tools are fail-closed — absent from the tool list until TOOLKIT_ENABLE_NET_DIAGNOSTICS or TOOLKIT_ENABLE_SYSTEM_INFO is set — and even with diagnostics on, private, reserved, loopback and link-local targets stay blocked until TOOLKIT_ALLOW_PRIVATE_NETWORK is set as well.
Setup effort
One command — npx -y @cyanheads/toolkit-mcp-server