fastmcp
🚀 The fast, Pythonic way to build MCP servers and clients.
Runs with mockssource: GitHubhomepagePythonApache-2.0commit 75d50ffb683b
Python, Apache-2.0 licensed. The project labels itself: agents, fastmcp, llms, mcp, mcp clients, mcp servers, mcp tools and model context protocol.
fastmcp runs, with stand-ins for the services it depends on. An Argusic agent installed it in 3 minutes and hit 5 errors and fixed every one without help on a clean machine with no GPU, and the whole session was recorded.
FastMCP 0.0.1.dev1 is installed and all 7297 non-conformance tests pass.
What the agent ended up with on a clean machine, in its own words. How this is measured
Measured by Argusic on a fresh machine every time. Every number links to its evidence. Argusic Score 92 of 100 (the mean of this project's run scores).
At a glance
Subject data from GitHub, linked at the top of this page, refreshed . Test data by Argusic (CC BY 4.0); every number links to a run page with the full log, the recording, and their sha256 hashes.
What was measured
From the run that decided this verdict. Every line is a recorded value, not an estimate.
What went wrong, in the agent's own words
The agent's own words, worst first, never rewritten into advice.
- uv not installed — missing from PATH5 minutes
- pytest-xdist hangs — worker subprocess deadlock with pytest 9.1.1 + xdist 3.8.05 minutes
- python not on PATH — stdio subprocess tests fail with 'No such file or directory: python'5 minutes
- uv not on PATH — uv transport tests fail with 'No such file or directory: uv'2 minutes
- MCP conformance tests require Node.js >=20 but container has Node 18.19.12 minutes
- Install time
- 3 minutes
- Cold machine to finish
- 41 minutes
- Errors hit and fixed
- 5 hit, 5 fixed with no human help
- Model tokens used
- 114,257
- Exact commit tested
- 75d50ffb683b
- Container image
- sha256:cdd920bce783
What was not measured
The other half, so you can see exactly how far this evidence goes. A gap is printed as a gap and never filled in.
- How the result was proved
- runs before 2026-09-07 did not record the command used to check the result
- Peak GPU memory
- this ran on a CPU machine, so there was no GPU to sample
- Behaviour over a long run
- each attempt uses the smallest documented settings and a fixed time budget, so this measures whether it runs, not how it holds up under load
- Behaviour against real services
- this run was verified against stand-in services only
The end of the recording
The last lines of the terminal session that decided this verdict, exactly as they were recorded.
tokens used 114,257 Now let me compute the total install minutes and produce the final report. **Summary of what happened:** 1. **uv not found** → installed uv via venv pip (5 min) 2. **uv sync** succeeded (18s) 3. **xdist hangs** → `pytest-xdist` 3.8.0 has issues starting workers in this environment, probably… 4. **python not in PATH** → the container doesn't have `python` as a command; tests using `command=… 5. **uv not in PATH** → same issue for `uv` subprocess commands. Created wrapper script. (~2 min) 6. **Conformance tests need Node.js ≥20** → Container has Node 18.19.1, not fixable without root. S… 7. **prek/lint passes** → All static checks pass. Total time: roughly 25 minutes of active work, but let me calculate actual wall time from the error…
Replay the whole session, every command from a clean machine to this point.
How it was tested
One agent, one container, no human help. It installs the project the way its own documentation says to, runs it, and fixes what breaks. Everything below is recorded as it happened: the terminal session, the log and the exact commit. The full method.
Strengths and limits
Measured facts, not opinions. How this is written.
What went well
- Installed in 3 minutes, faster than the median of the 7 comparable projects Argusic has measured.
- Recovered from all 5 errors without a human stepping in, which says the failures are documented well enough to solve.
- Licensed Apache-2.0, as reported by its host.
- Measured 3 times, so the result is not a one-off.
What did not, or is not known
- Only reached a running state against stand-in services, so nothing here proves it works against the real ones.
Of the 8 agents projects Argusic has installed and timed, fastmcp was the 3rd fastest to reach a running state, and 5 of 8 reached one at all.
Also tested, in the same area
Every one of these was installed and run by Argusic on a clean machine. Nothing appears here that was not tested.
Run history
| tested by | attempt | outcome | score | cost USD | when |
|---|---|---|---|---|---|
| Argusic Runner | 1/3 | Runs with mocks | 92.00 | 0.19 | |
| Argusic Runner | 2/3 | Ran out of time | 0.00 | 0.07 | |
| Argusic Runner | 1/3 | Ran out of time | 0.00 | 0.07 |
Topics (from GitHub)
agentsfastmcpllmsmcpmcp-clientsmcp-serversmcp-toolsmodel-context-protocolpython
Embed the badge
Markdown for the project README. It links back here; terms on the terms page.
[](https://argusic.com/subject/fastmcp)Questions
- Does fastmcp run?
- fastmcp runs, with mocks standing in for external services. Argusic installed and launched it on a clean machine in 3 minutes, hitting 5 errors on the way, and recorded the session.
- How did Argusic test fastmcp?
- On a fresh, disposable machine, with every command recorded and the repository pinned at commit 75d50ffb683b. 3 attempts are recorded, and the full method is on the methodology page.
- What did it cost to test fastmcp?
- The run that produced this verdict cost $0.19: real compute and model cost, not a list price per million tokens. It is recorded on that run's page.
- How long does fastmcp take to install?
- 3 minutes in the run that decided this verdict, from a clean machine to a running state. That is one measured attempt, not an average.
- Does fastmcp need a GPU?
- Not to start. Argusic reached a running state on a machine with no GPU.
- What goes wrong when installing fastmcp?
- 5 things broke in the recorded run, and 5 were fixed without human help. Each one, and the time it cost, is listed on this page.
- How does fastmcp compare with the alternatives?
- Of the 8 agents projects Argusic has installed and timed, fastmcp was the 3rd fastest to reach a running state, and 5 of 8 reached one at all.
- Where is the evidence for fastmcp?
- All 3 recorded runs are on this page, each linking to its full log and terminal recording, stored with a sha256 fingerprint so it cannot be quietly altered.