fastmcp

fastmcp is a skill for Claude Code, Codex from NousResearch/hermes-agent. It costs 14 tokens per session (1,897 once invoked), scanned A, original, MIT.

A toolkit for building MCP servers in Python. MCP, or Model Context Protocol, lets AI applications use tools, data sources, and prompts provided by another program.

In plain words
What is it for?
Use it to create, locally test, install, and deploy Python MCP servers, including servers that expose tools, resources, or prompts.
Why use it?
It gives you a defined way to turn an API, database, command-line tool, or file workflow into something an MCP client can use and test.

Skill for Claude CodeCodex

Which agent this was written for is unclear — built for hermes-agent. Also seen: mentions Claude Code; built for hermes-agent.

Good fit Use it to create, locally test, install, and deploy Python MCP servers, including servers that expose tools, resources, or prompts.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/nousresearch/hermes-agent/fastmcp
About the project

Hermes Agent is an AI assistant that learns from its use by creating and improving skills, retaining knowledge, searching past conversations, and adapting to its users. It is for people who want to run an agent through a terminal or messaging platforms while connecting it to different AI models and scheduled tasks.

NousResearch/hermes-agent · 243,146 stars · on GitHub · hermes-agent.nousresearch.com

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 NousResearch/hermes-agent --skill fastmcp
Clone the repo
git clone --depth 1 https://github.com/NousResearch/hermes-agent

Made for: Claude Code, Codex.

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 fastmcp

README.md
[![agentmods](https://agentmods.dev/badge/skills/nousresearch/hermes-agent/fastmcp/github.svg)](https://agentmods.dev/skills/nousresearch/hermes-agent/fastmcp)
Your own site
<a href="https://agentmods.dev/skills/nousresearch/hermes-agent/fastmcp"><img src="https://agentmods.dev/badge/skills/nousresearch/hermes-agent/fastmcp/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 fastmcp

Your own site · 80×15
<a href="https://agentmods.dev/skills/nousresearch/hermes-agent/fastmcp"><img src="https://agentmods.dev/badge/skills/nousresearch/hermes-agent/fastmcp.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 14 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,897 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe. Third-party audits
  • Snyk pass 7 Sept 2026
  • NVIDIA SkillSpector warn 7 Sept 2026
SkillSpector: 3 findings, up to medium

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 →

  • medium Rogue Agent · line 25
    Skill establishes unauthorized persistence across sessions via cron jobs, startup scripts, or state files. Session persistence allows an attacker to maintain access beyond the current interaction.
    Fix: Remove any persistence mechanisms (cron jobs, startup scripts, state files). Skills should not maintain state across sessions without explicit user consent.
  • low MCP Rug Pull · line 39
    pip install without ==version installs the latest release, which could include malicious changes.
    Fix: Pin the version: pip install package==1.2.3
  • low MCP Rug Pull · line 271
    pip install without ==version installs the latest release, which could include malicious changes.
    Fix: Pin the version: pip install package==1.2.3
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 $0.00014 $0.01897
Opus 5 $0.00007 $0.00949
Sonnet 5 $0.00003 $0.00379
Haiku 4.5 $0.00001 $0.00190

Measured 9d ago against content hash f4072408b8b5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

fastmcp scanned grade A with 0 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 9d ago.

The scan reads SKILL.md. This mod also ships 4 executable files (scripts/scaffold_fastmcp.py, templates/api_wrapper.py, templates/database_server.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.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

8 near-identical copies found in the catalogue:

  • fastmcp — 100% identical, 0 lines differ
  • fastmcp — 100% identical, 2 lines differ
  • fastmcp — 100% identical, 0 lines differ
  • fastmcp — 94% identical, 7 lines differ
  • fastmcp — 94% identical, 6 lines differ
  • fastmcp — 94% identical, 7 lines differ
  • fastmcp — 94% identical, 6 lines differ
  • fastmcp — 94% identical, 6 lines differ
optional-skills/mcp/fastmcp/SKILL.md · 301 lines

How it starts

The opening of the file, as written. The whole thing — 301 lines — stays where its author put it; the contents beside it link to each section on GitHub.

FastMCP

Build MCP servers in Python with FastMCP, validate them locally, install them into MCP clients, and deploy them as HTTP endpoints.

When to Use

Use this skill when the task is to:

  • create a new MCP server in Python
  • wrap an API, database, CLI, or file-processing workflow as MCP tools
  • expose resources or prompts in addition to tools
  • smoke-test a server with the FastMCP CLI before wiring it into Hermes or another client
  • install a server into Claude Code, Claude Desktop, Cursor, or a similar MCP client
  • prepare a FastMCP server repo for HTTP deployment

Use native-mcp when the server already exists and only needs to be connected to Hermes. Use mcporter when the goal is ad-hoc CLI access to an existing MCP server instead of building one.

Prerequisites

Install FastMCP in the working environment first:

pip install fastmcp
fastmcp version

For the API template, install httpx if it is not already present:

pip install httpx

Included Files

Templates

  • templates/api_wrapper.py - REST API wrapper with auth header support
  • templates/database_server.py - read-only SQLite query server
  • templates/file_processor.py - text-file inspection and search server

Scripts

  • scripts/scaffold_fastmcp.py - copy a starter template and replace the server name placeholder

References

  • references/fastmcp-cli.md - FastMCP CLI workflow, installation targets, and deployment checks

Workflow

1. Pick the Smallest Viable Server Shape

Choose the narrowest useful surface area first:

  • API wrapper: start with 1-3 high-value endpoints, not the whole API
  • database server: expose read-only introspection and a constrained query path
  • file processor: expose deterministic operations with explicit path arguments
  • prompts/resources: add only when the client needs reusable prompt templates or discoverable documents

Prefer a thin server with good names, docstrings, and schemas over a large server with vague tools.

Read the full file on GitHub · 301 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. 9d ago First seen · 301 lines · 14 tokens per session scan A f4072408b8b5

Subscribe to this mod's changes

fastmcp is a skill published in the GitHub repository NousResearch/hermes-agent (243,146 stars, last pushed today), licensed MIT. It adds 14 tokens to every session and 1,897 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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