mcp-to-skill

mcp-to-skill is a skill for Claude Code from Mathews-Tom/armory. It costs 68 tokens per session (2,326 once invoked), scanned B, original, MIT.

A converter that turns MCP servers—programs that give an agent access to external tools—into skills loaded only when needed.

In plain words
What is it for?
Use it to decide which MCP tools to convert, keep, or combine, and to generate the resulting skill package.
Why use it?
It reduces the amount of tool description text added to every conversation, leaving more context for the actual task.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: reads .claude/ paths; mentions Claude Code.

Part of the armory plugin — 85 skills shipped together

Good fit Use it to decide which MCP tools to convert, keep, or combine, and to generate the resulting skill package.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/mathews-tom/armory/mcp-to-skill
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add Mathews-Tom/armory --skill mcp-to-skill
Clone the repo
git clone --depth 1 https://github.com/Mathews-Tom/armory

Made for: Claude Code.

Or install armory, the plugin that ships this one along with the rest of its 85 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for mcp-to-skill

README.md
[![agentmods](https://agentmods.dev/badge/skills/mathews-tom/armory/mcp-to-skill/github.svg)](https://agentmods.dev/skills/mathews-tom/armory/mcp-to-skill)
Your own site
<a href="https://agentmods.dev/skills/mathews-tom/armory/mcp-to-skill"><img src="https://agentmods.dev/badge/skills/mathews-tom/armory/mcp-to-skill/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for mcp-to-skill

Your own site · 80×15
<a href="https://agentmods.dev/skills/mathews-tom/armory/mcp-to-skill"><img src="https://agentmods.dev/badge/skills/mathews-tom/armory/mcp-to-skill.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 68 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,326 The whole file, excluding the scripts and references it only reads on demand.
Security scan B 2 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 1 finding, up to high

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

  • high Agent Snooping · line 56
    Skill reads from agent configuration directories (.claude/, .codex/, .gemini/). These directories may contain API keys, personal settings, and other credentials that the skill has no legitimate need to access.
    Fix: Remove all code or instructions that access agent configuration directories (.claude/, .codex/, .gemini/). If configuration values are needed, pass them explicitly as parameters or environment variabl
How audits are shown
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00068 $0.02326
Opus 5 $0.00034 $0.01163
Sonnet 5 $0.00014 $0.00465
Haiku 4.5 $0.00007 $0.00233

Measured 10d ago against content hash cb01e6ec0de9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade B, and why

mcp-to-skill scanned grade B with 2 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/estimate_tokens.py), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Reads agent configuration directoriesmediumAgent snooping

.claude/, .codex/, .gemini/ hold keys, settings and other credentials a mod has no legitimate need for.

- Claude Code: `~/.claude/settings.json` or project `.mcp.json`

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

**Convert when** the MCP wraps a REST API (use curl/web_fetch), wraps a CLI tool
skills/mcp-to-skill/SKILL.md · 239 lines

How it starts

The opening of the file, as written. The whole thing — 239 lines — stays where its author put it; the contents beside it link to each section on GitHub.

MCP-to-Skill Converter

Convert MCP servers into on-demand skills. MCP tool schemas sit in the system prompt on every turn (~500-2000 tokens per tool, regardless of whether they're used). Skills cost zero tokens until loaded via view. For a typical setup with 4-5 MCP servers exposing 20-40 tools, this reclaims 10,000-30,000 tokens of context per turn.

This matters because that's 10-30% of the context window burned before the conversation even starts — and it compounds: every turn re-injects the full schema.

Decision Framework: Convert vs. Keep

Not every MCP should become a skill. Apply this heuristic:

Convert when the MCP wraps a REST API (use curl/web_fetch), wraps a CLI tool (gh, aws, gcloud — invoke directly), implements a reasoning/planning pattern (capture as methodology), or when you use fewer than half its tools regularly.

Keep as MCP when it maintains persistent server-side state (DB connections, WebSocket sessions), handles binary protocols or streaming, provides real-time event subscriptions, or is tiny (1-2 tools, under 500 tokens — negligible overhead).

Hybrid approach — convert the stateless tools to a skill, keep stateful ones as a slimmed-down MCP. This is often the sweet spot for large MCP servers.


Conversion Workflow

Proceed through 5 phases. Present findings at each phase boundary and wait for user confirmation before continuing. The user knows their usage patterns better than any analysis can infer — lean on their input.

Phase 1: Discovery

Acquire the MCP's tool definitions. Try these sources in order:

  1. Active session tools — Inspect tools visible in the current conversation. Ask the user to identify which tools belong to the target MCP. This is the most reliable source because you see the exact schema consuming context.

  2. MCP config file — Parse the user's MCP configuration:

    • Claude Desktop: ~/Library/Application Support/Claude/claude_desktop_config.json
    • Cursor: .cursor/mcp.json in the project root
    • Claude Code: ~/.claude/settings.json or project .mcp.json
    • Config files give server names and connection details, not tool schemas.

Read the full file on GitHub · 239 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 239 lines · 68 tokens per session scan B cb01e6ec0de9

Subscribe to this mod's changes

mcp-to-skill is a skill published in the GitHub repository Mathews-Tom/armory (316 stars, last pushed 4d ago), licensed MIT. It adds 68 tokens to every session and 2,326 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it B with 2 findings (reads agent configuration directories, makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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