mcptoon is a clearly scoped control layer for MCP tools, addressing two real pains: tool schemas eating the context window, and every agent re-configuring the same tools. Its headline figures come from the project's own tiktoken cl100k_base benchmark (255 tools: 71,929 → 581 tokens, −99.2%), and the README cites external measurements from Anthropic, Firecrawl and Scalekit to back the general claim that loading full schemas is expensive. Strengths: zero dependencies, no daemon, no telemetry, bundles no servers, and it can be deleted without breaking your servers. Limits: it requires an agent that can run shell commands, ships no ready-made toolset, and asks users to install MCP servers themselves, taking on the corresponding supply-chain risk. It is not an Anthropic official project.
mcptoon is a 156KB CLI built entirely on the Python standard library with zero third-party dependencies. It keeps MCP tool schemas out of the agent's context window: by default it emits only a name index, and the project's own measurement puts 255 tools at 581 tokens instead of 71,929 (−99.2%), with a further ~34% saving on call results via --toon. It also acts as a shared configuration layer for multiple agents: configure servers once in ~/.mcptoon/config.json, and any agent that can run a shell command (Claude Code, Cursor, Codex, scripts, CI) can use the same servers and tools — new tools go live without restarting the agent and without hand-editing per-agent JSON. mcptoon bundles no MCP servers; it is a control layer, not a runtime. Servers are installed by the user (npm/pip/URL), start only when called, and keep running independently if mcptoon is deleted. It bridges MCP over stdio and can also run as an MCP server, and it ships three built-in guards: destructive-action blocking, prompt-injection scanning, and credential-leak detection.
1) Install: pip install mcptoon (pure stdlib, 156KB, zero dependencies). 2) Prove it: run mcptoon demo --quick — it boots the official everything reference server and prints the token math; no API key needed. 3) Add an MCP server: mcptoon add everything --stdio npx -y @modelcontextprotocol/server-everything, or mcptoon install brave-search --npm @modelcontextprotocol/server-brave-search. 4) See the tool index: mcptoon manifest (compact by default; 255 tools ≈ 581 tokens). 5) Call a tool: mcptoon call everything echo '{"message":"hi"}', add --toon to compress the result. 6) Share config across agents: mcptoon sync writes native JSON into each agent's own location, or run mcptoon quickstart to discover, configure and list in one command. 7) Claude Code users can install the plugin via /plugin marketplace add activeing123/mcptoon.