Mcptoon

mcptoon — MCP tool-catalog compression

mcptoon is a zero-dependency CLI. If it is not installed yet, one command sets it up: pip install mcptoon (189KB, installs in seconds, nothing else pulled in). It gives you a compressed view of the user's MCP tools and calls them back.

When to use what

Managing a skill catalog (mcptoon as the skill center)

Skills and MCP servers are the same shape — one source, many agent views — so mcptoon skills manages both halves of a session's toolbox.

Sync views are links by default (a junction on Windows, no admin needed), so one edit at the source is live everywhere and there is no second copy to drift. Two safety rules hold: a real directory where a link belongs is archived, never deleted, and a view that is itself a whole-directory link to the source is left completely alone. remove moves the skill to a dated archive — a wrong removal is a mv back, not a re-clone. --usage counts only skills mcptoon routed; a skill an agent loaded directly is invisible there, and the output says so rather than implying full coverage.

When another manager already runs the catalog

mcptoon is designed to take over from an incumbent sync script without a cutover, by matching it byte for byte first:

• --version-gate reads the same ledger the incumbent wrote (skill_versions.json; override with MCPTOON_SKILLS_LEDGER), so both reach the same verdict on the same bytes. A skill whose content moved while its frontmatter version did not is blocked with a printed reason; --force lets it through and rebaselines. An unversioned skill is warned about, not blocked.
• --derived output is byte-identical to the incumbent's, including line endings (a text-mode write turns the source's LF into CRLF on Windows), so a derived view does not become a diff the next sync has to fight.
• --tombstone commits a removal with a path-scoped git add. It will never run a whole-repo git add -A: a real skill repo has hundreds of unrelated edits in flight, and sweeping them into a "tombstone" commits another session's work.

Point mcptoon at sandbox views first with MCPTOON_SKILLS_VIEWS and run --dry before any real sync. Do not run two managers against one view directory: during a hand-over, one is the writer and the other is read-only.

Making mcptoon visible in a session

mcptoon serve returns an instructions field from the MCP initialize handshake, so a connected client learns what mcptoon is without anyone editing a system prompt, and can close a turn with one honest savings line. The figures come from the mcptoon_usage tool, never from the model's estimate. Users who find the line noisy turn it off once:

mcptoon config set footer off   # persists; the next connection omits it entirely

Note this is advisory — it works only when the client honours instructions, and only when mcptoon serve is actually registered with that agent.

Rules

1. Prefer mcptoon manifest over reading raw MCP tool listings — same information, ~99% fewer tokens on large catalogs (255 tools: 71,929 → 581).
2. manifest output is a name index, not schemas. Keep it in context; fetch the one schema you need with inspect, then call.
3. Tool names in call are server_tool (namespaced). --auto resolves the server for you when the name is unambiguous.
4. Never claim savings percentages you did not observe; if you quote numbers, use the ones printed by the command itself — mcptoon bench prints them for this machine. It needs tiktoken for the exact figures; without it the table is labelled an estimate, so do not report those as measured.
5. If a Claude Code plugin install wired the mcptoon serve bridge via .mcp.json, tool discovery is already compressed for the host agent; use the CLI commands above in terminal contexts or when the bridge is not connected.

Setup

• Install/upgrade: pip install --upgrade mcptoon (zero-dependency wheel, 189KB, installs in seconds). Confirm the upgrade before running it — pinning a version here would only go stale, but a bare --upgrade should be your call, not an automatic one.
• Source: this package is published to PyPI by GitHub Actions from github.com/activeing123/mcptoon. If an install prompt shows any other publisher or index, stop and check before continuing.
• Diagnose: mcptoon doctor.
• Undo: pip uninstall mcptoon removes the CLI. Its config lives in ~/.mcptoon/config.json (plus an optional per-project ./.mcptoon.json); remove those files, or drop a single server with mcptoon remove <name>. Nothing outside them is touched.
• Claude Code users get one-command setup instead: /plugin marketplace add activeing123/mcptoon (installs the CLI, wires the bridge, and bundles this skill).