Mcptoon Agent Skill

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

| Situation | Command |

|---|---|

| User asks "what tools do I have" / you need the tool catalog | mcptoon manifest (compact names only — ~2.2 tokens/tool) |

| You need one tool's real parameter schema before calling | mcptoon inspect <server> <tool> |

| Find a tool by capability | mcptoon search <query> |

| Call a tool | mcptoon call <server> <tool> '{"arg":"value"}' |

| You don't know which server owns the tool | mcptoon call --auto <tool> '{...}' |

| Huge JSON argument | mcptoon call <server> <tool> --stdin |

| Tool returns images/base64 that must never be compressed | mcptoon policy set <server> <tool> raw (one-time; applies to every later call) |

| Prove the token savings on this machine (tools + skills, one table) | mcptoon bench (--roots DIR for any catalog; --json for scripts) |

| Diagnose connectivity/config | mcptoon doctor |

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.

| Situation | Command |

|---|---|

| See what skills exist | mcptoon skills list (--usage adds per-skill hit counts) |

| Find the right skill for a task | mcptoon skills resolve "<task>" (offline, instant, no LLM) |

| Distribute one source to every agent's skill folder | mcptoon skills sync [SRC] [VIEW ...] (--dry to preview, --copy for real dirs) |

| Refuse "edited but forgot to bump the version" | mcptoon skills sync --version-gate |

| Regenerate the flat .md views (Roo / OpenCode) | mcptoon skills sync --derived roo\|opencode\|all |

| Create / retire a skill | mcptoon skills add <name> --desc "…" / mcptoon skills remove <name> |

| Retire a skill so a git sync cannot revive it | mcptoon skills remove <name> --tombstone |

| Park drift/removals in a chosen graveyard | add --archive DIR to sync or remove |

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

• Prefer mcptoon manifest over reading raw MCP tool listings — same

information, ~99% fewer tokens on large catalogs (255 tools: 71,929 → 581).

• manifest output is a name index, not schemas. Keep it in context;

fetch the one schema you need with inspect, then call.

• Tool names in call are server_tool (namespaced). --auto resolves

the server for you when the name is unambiguous.

• 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.

• 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).