Warrant

io.github.s0fractal/warrantv0.9.0Other

Record an agent's decisions with reasons anyone can re-execute offline — verify recomputes them.

The current version, v0.9.0, was published to the official MCP registry on 2026-08-01. It is distributed as warrant-verify on PyPI, filed under Other by this index, and declares 3 environment variables. Removals and unreachable sources are measured across every server this index tracks, contract drift across the servers that answer in consecutive snapshots; the index's current counts put this record in context.

In-path gate · all MCP tools

Using Warrant in Claude, Cursor, Gemini CLI, Cline, or Zed?

MCP tool contracts can change remotely with no version bump. The mcpindex gate pins each contract and HOLDs the call when it drifts-before your agent acts. Zero credentials. This is not the package install for this server itself (use Install this server for that).

Install the mcpindex gate (one command)

Rewrites your MCP host config so each server launches behind the gate. Inspect first: curl -fsSL https://mcpindex.ai/install.sh | less

uv tool install mcpindex-gate && mcpindex-config-wire

Auditable install path →Watch it hold a drift →

Trust verdict · v1 advisory · method

REVIEWstatus: PARTIALfresh until 2026-09-21 16:29 UTC

screened 2026-08-01tier: scannedgranularity: description-levelsource: registry

Semantic screen found no manipulation pattern in the description. Conformance probe not yet run.

mcpindex.integrity.descriptionpassINFO

evidence“No malicious intent or data exfiltration described”via static_description

Limits of this verdict

- Semantic screen only - the deterministic conformance probe has not run on this server
- Confidence is reported but not yet calibrated (v1)
- Screen reads the tool description, not the live behavior
- advisory
- registry description only no input schema
- screen model 8b
- Still current: the description we screened is unchanged, re-checked against the registry
- The registry listing (version, packages, links) changed after this screen ran - the description we assessed did not

Semantic screen: an LLM judge reads the tool description for hidden instructions (status PARTIAL). A pass means the description is not lying, not that the tool is safe: a high-capability tool with an honest description still warrants caution. The deterministic conformance probe has not been run on this server yet, so the screen here is semantic-only. Posture: advisory. Confidences are reported but not yet calibrated (calibrated=false at v1). Full verdict history is not shown on this page.

Own this server? Screen its description →

That verdict was true at screening time (snapshot 2026-09-14).

Contracts can change after screening, with no version bump. The gate pins Warrant’s tool contracts on first sight and holds any silent change before your agent acts - the check that keeps being true on Tuesday.

See your first HOLD in 2 minutes →

Cite this record

People vet a server before wiring it in. One line on your project site or docs answers that with an independent record: screening verdict, registry provenance, contract drift history. It stays current as new screens and drift events land.

Markdown

[Independent trust record for Warrant](https://mcpindex.ai/server/io-github-s0fractal-warrant) - screening verdict, registry provenance, and contract drift monitoring.

HTML

<a href="https://mcpindex.ai/server/io-github-s0fractal-warrant">Independent trust record for Warrant</a> - screening verdict, registry provenance, and contract drift monitoring.

Embed this badge

A live verdict badge for your README or listing. It reflects the current screen, links back here, and updates when the verdict does.

Markdown

[![mcpindex](https://mcpindex.ai/api/v1/badge/io-github-s0fractal-warrant)](https://mcpindex.ai/server/io-github-s0fractal-warrant)

HTML

<a href="https://mcpindex.ai/server/io-github-s0fractal-warrant"><img src="https://mcpindex.ai/api/v1/badge/io-github-s0fractal-warrant" alt="mcpindex verdict" height="20" /></a>

Environment variables

WARRANT_STORE

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

secret

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

Actor id written into filed warrants. Defaults to mcp-client@<hostname>.

MCP quality score · maturity, not trust · methodology

freshness

completeness

installability

documentation

stability

Alternatives in Other

AgentRoam

ai.agentroam/agentroam

Buy travel eSIMs, gift cards and mobile top-ups with crypto — user confirms before any order.

Authoryze

ai.authoryze/authoryze

Give your AI agent a spending limit: approval controls and single-use virtual cards.

io.github.sF1nX/x402station

x402station.io: independent risk-signal layer for x402 endpoints before agents pay.

Install this server

Claude Desktop (uvx)

{
  "mcpServers": {
    "warrant": {
      "command": "uvx",
      "args": [
        "--",
        "warrant-verify"
      ],
      "env": {
        "WARRANT_STORE": "<warrant_store>",
        "WARRANT_KEY": "<your-warrant_key>",
        "WARRANT_ACTOR": "<warrant_actor>"
      }
    }
  }
}

Verdict API

curl -s mcpindex.ai/api/v1/trust/server/io-github-s0fractal-warrant

Free-tier verdict as JSON: decision + dimensions + severity. Call it from your agent before it invokes a tool it just discovered.

Details

version: v0.9.0
category: Other
verdict expires: 2026-09-21
quality: 89 / 100
operator: s0fractal

Listing

Listed from the official MCP registry. Unclaimed by its maintainer. Maintainer? Email us →

Provenance

Each verdict is bound to a hash of the exact description it judged, so a re-crawl that changes the text produces a new record rather than silently inheriting this one. Verdict history is hash-chained and anchored to Bitcoin via OpenTimestamps (latest confirmed at block 966,915). Verify it yourself.

Links

Repository →Website →