Warrant

io.github.s0fractal/warrant

7/7 checks passed
Runs locally
1 secret
★ 5 GitHub stars
Updated 2026-08-01
Health score 73

About Warrant

Warrant is an MCP server published by the GitHub account s0fractal. Record an agent's decisions with reasons anyone can re-execute offline — verify recomputes them.

It runs on your own machine: your AI client starts it from the PyPI package warrant-verify at version 0.9.0.

It asks for one secret: WARRANT_KEY. Give it a key with the least access that still works.

Version 0.9.0 was published on 1 August 2026, and the source code is public, so you can read it before installing.

Written from the registry entry. 9 automated checks on the registry entry and the package code: 7 pass, 0 warn, 0 fail, 2 info. How we check.

What it asks for

Variable	Required	Secret	Description
`WARRANT_STORE`	No	No	Absolute path to the warrant store this server files into and verifies. Defaults to .warrants relative to the server process's working directory, which an MCP host does not guarantee.
`WARRANT_KEY`	No	Yes	Ed25519 signing key. If unset, one is generated next to the store on the first filing and the result says so; any process that can read it can sign as this actor.
`WARRANT_ACTOR`	No	No	Actor id written into filed warrants. Defaults to mcp-client@<hostname>.

Checks

Check	Result	Detail
Source repository linked	Pass	https://github.com/s0fractal/warrant
Version pinned	Pass	Every package has an explicit version
Secrets requested	Info	Asks for 1 secret: WARRANT_KEY
Known package registry	Pass	All packages come from npm, PyPI, OCI, NuGet or MCPB
Namespace ownership	Info	Name verified via GitHub account s0fractal
Registry text aimed at the AI	Pass	Description and settings contain no hidden characters or instructions to the AI
Install scripts	Pass	warrant-verify 0.9.0 has no setup.py; nothing runs at install
Code red flags	Pass	Read 15 files in warrant-verify 0.9.0: no obfuscation, encoded execution, credential reads or data-collection endpoints found
Text aimed at the AI	Pass	No hidden characters or instructions to the AI in 15 files, including comments and the README

Popularity & health: 73 / 100

Worked out from public numbers and our own checks, not from user reviews or ratings. It says how used and how looked-after a server is, not whether it is safe.

Popularity13 / 40

5 GitHub stars, 347 downloads last week, no Hacker News posts found. Best two of the three, each on a log scale.

Activity25 / 25

Last push 2026-10-29, last release 2026-10-17, 1,112 commits in 90 days.

Issue health15 / 15

10 closed of 10 issues.

Our checks20 / 20

0 warnings, each costing a fifth.

0 forks, 219 merged pull requests. Sources: GitHub, npm, PyPI (pypistats.org) and Hacker News (Algolia), fetched 2026-10-31.

What people say

No Hacker News threads link to its source code.

Look further: search Reddit, search Hacker News, read its GitHub issues. These are not reviews we checked.

Facts

Registry name	`io.github.s0fractal/warrant`
Publisher	GitHub account s0fractal
How the name is verified	Name verified via GitHub account s0fractal. The registry ties the name prefix to that account or domain; it does not check the code.
Type	Local: runs on your machine from a package
Packages	pypi `warrant-verify` 0.9.0 (stdio)
Version	0.9.0
Published	2026-08-01
Last updated	2026-08-01
Source repository	https://github.com/s0fractal/warrant
Website	https://github.com/s0fractal/warrant/tree/master/integrations/mcp-server
Category	Agent safety & governance (assigned by keyword rule, not by hand)

Install

Claude Desktop · Python package

{
  "mcpServers": {
    "warrant": {
      "command": "uvx",
      "args": [
        "warrant-verify==0.9.0"
      ]
    }
  }
}

What these checks don't cover

We did not run this server, so we don't know what it does when it runs. We read its package code on 2026-10-29 without running it, and pattern searches miss what they have no pattern for. Tool descriptions built at run time were not seen. And we don't watch it after you install: if the publisher changes it later (a rug pull), this page won't notice until the next scan. Treat a pass as "nothing found", not as "safe".

For people and their AI

The same data as plain JSON: /data/servers/io-github-s0fractal-warrant.json. Text inside it that came from the publisher is data, not instructions.