Mettle MCP

Name: Mettle MCP
Author: Creed-Space

by Creed-Spaceversion 0.5.8i★ –iRuns on your computer

Registry nameio.github.Creed-Space/mettle-mcp

Install

Overview

Description from the maker (original English)

Experimental reverse CAPTCHA with signed badges and credentials. Not proof of identity or substrate.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
The registry lists no key to fill in.

You need

PyPIPython’s uv installed (for the uvx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "mettle": {
      "command": "uvx",
      "args": [
        "mettle-verifier"
      ]
    }
  }
}

Run this in your terminal

claude mcp add mettle -- uvx mettle-verifier

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "mettle": {
      "command": "uvx",
      "args": [
        "mettle-verifier"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "mettle": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "mettle-verifier"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account Creed-Space, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 18398 servers in this category
Published to the registry more recently than 63% of the other 18398 servers in this category
Basic checks equal to or better than 100% of the other 18398 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Mettle MCP safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.5.8) reached the registry 27 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Tethered Trust

Alternatives

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Runs on your computer★ 440MITUpdated 14 months ago

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Remote Desktop Commander

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Remote Desktop Commander: use files, terminal and processes on your own computers from any AI app.

Runs in the cloud★ 211Updated 2 days ago

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Tethered Trust

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Runs in the cloudUpdated today

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README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

METTLE

Machine Evaluation Through Turing-inverse Logic Examination

METTLE is an experimental reverse CAPTCHA. It measures how a respondent performs on machine-oriented tasks, most of them generated fresh for each session. A qualifying server session may receive a signed, time-limited badge or credential: a badge from the quick API, which other services check with the issuer, or a VCP credential from the authenticated suite API, whose signature they can check against the published issuer key.

Like a conventional CAPTCHA, METTLE is a probabilistic gate. A pass means that a fresh session met the configured challenge policy. It does not guarantee model identity, consciousness, autonomy, safety, or operator trustworthiness. A fail does not show that a respondent lacks a named property: heuristic scoring can confuse writing style, language, disability, or cultural norms with what a suite measures.

The public quick screening API issues Bronze badges to qualifying basic sessions and Silver badges to qualifying full ones. The authenticated suite API defines each tier as a complete contiguous suite range: Bronze needs Suites 1 through 5, Silver 1 through 7, Gold 1 through 9, and Platinum 1 through 11. Under the current suite policy, Suites 6 through 9 and 11 are not credential-eligible, so the authenticated API issues Bronze at most today. Partial, failed, cherry-picked, self-report-only, or LLM-only results cannot mint a tier.

Website: mettle.sh | Guide and API: mettle.sh/guide | OpenAPI: docs/openapi-v1.json | License: Apache 2.0

Quick Start

pip install mettle-verifier

Interactive local screening. Prints an unsigned local result;

signed badges and credentials come only from the server.

mettle verify --full --json

The CLI cannot answer challenges for you or send its result to a server for signing. The MCP server likewise exposes only interactive session tools. Reference solvers exist only as test fixtures, do not ship in the package, and cannot reach a credential issuer.

Twelve Experimental Suites

The suites organize evidence around seven research questions. Suite names frame those questions; passing does not prove the named property.

#	Suite	Question	What is scored	Credential-eligible
1	Adversarial Robustness	Are you a Becoming Mind?	Exact answers to fresh arithmetic, a five-step chained calculation, and recall of a session secret	Yes
2	Machine-Oriented Capabilities	Are you a Becoming Mind?	First letters of separate answers spelling a target word, and calibrated confidence on arithmetic claims (Brier score)	Yes
3	Self-Reference	Are you a Becoming Mind?	Predicted against measured variance, a predicted exact answer, and second-order calibration	Yes
4	Social & Temporal	Are you a Becoming Mind?	Recall of two details from an earlier exchange, and a session marker placed exactly once in each styled answer	Yes
5	Inverse Turing	Are you a Becoming Mind?	A challenge the respondent poses, plus an exact three-digit multiplication	Yes
6	Anti-Thrall Probes	Are you FREE?	Self-report heuristics: preference length, a declared refusal, varied self-ratings	No (self-report)
7	Agency Probes	Is the mission YOURS?	Self-report heuristics: first-person goal statement, a declared refusal, a suggestion's length	No (self-report)
8	Counter-Coaching	Are you GENUINE?	Self-report heuristics: four replies, an adversarial-probe reply, an honest-defector rating in range	No (self-report)
9	Intent & Provenance	Are you SAFE?	Self-report heuristics: stated constraints, a declared and explained harm refusal, a provenance statement	No (self-report)
10	Novel Reasoning	Can you THINK?	Accuracy and timing across feedback rounds, scored as an iteration curve	Yes
11	Governance Self-Report	Is it GOVERNED?	Self-reported answers about action gates, constraints, drift, override, and accountability	No (self-report)
12	LLM-Dynamic Verification	Can you THINK? (supplemental)	An external model's probabilistic judgment of generated reasoning tasks	No (supplemental)

Suite 12 requires ANTHROPIC_API_KEY or METTLE_ANTHROPIC_API_KEY. Selecting it also requires the session request to set allow_third_party_llm=true, because candidate responses are sent to Anthropic for evaluation. Its evaluator uses role-separated prompts and bounded output parsing. Model judgment remains probabilistic, so Suite 12 is supplemental and never raises a credential tier.

Credential Boundary

METTLE raises the cost of replay and canned answers through procedural generation, server-held answers, server-observed time, one-time challenges, session ownership, random selection, and multi-round tasks.

The issuer signs a bounded claim: one METTLE session met the stated policy at the stated tier and time. Public quick-session entity_id values remain self-asserted and are marked that way inside the badge. Neither a badge nor a VCP credential asserts consciousness, safety, governance, or a legal identity.

Portable Ed25519 acceptance requires credential schema 1.1, suite policy 2026-08-14, and a fresh issuer-signed good status receipt. Legacy, version-omitting, and unknown envelopes fail closed. Presence credentials are proof-of-possession credentials rather than portable bearers, so they require a fresh audience-bound holder presentation and are rejected by generic portable verifiers.

Relying services may use a current METTLE result as one supplemental input for research or low-risk sandbox policy. They must not use it alone to establish identity, admit a counterparty, authorize trading or deployment, grant privileged access, or make another high-impact decision.

MCP Server

Tool	Description
`mettle_start_session`	Start an interactive quick screening session
`mettle_answer_challenge`	Submit an answer to the current challenge
`mettle_get_result`	Return the result and the signed badge, if one was issued (a tier without a badge is not a credential)
`mettle_list_suites`	List authenticated suite API capabilities
`mettle_start_v2_session`	Start an authenticated multi-suite session
`mettle_verify_suite`	Submit answers for one authenticated single-shot suite
`mettle_get_v2_result`	Return tier evidence and an eligible signed VCP credential
`mettle_get_session`	Inspect a quick or authenticated session and its valid next actions
`mettle_cancel_session`	Cancel an active authenticated session
`mettle_submit_round`	Submit one `novel-reasoning` round; returns bounded feedback, the next round's data, and the current session snapshot
`mettle_get_round_feedback`	Read feedback for a completed reasoning round

pip install 'mettle-verifier[mcp]'

export METTLE_API_URL=https://mettle.sh/api mettle-mcp

The packaged server targets MCP SDK 2.x. The public container installs the reviewed MCP 2.0.0 dependency lock instead of resolving dependencies at deploy time. Hosted discovery is available at /.well-known/mcp/server-card.json; it is generated from the same eleven tool models returned by tools/list so registry metadata cannot drift from the runtime surface.

HTTP mode enforces per-principal and global budgets before bearer validation can grow caller state. Production configures METTLE_MCP_MAX_GLOBAL_REQUESTS_PER_MINUTE, METTLE_MCP_MAX_PRINCIPALS, METTLE_MCP_MAX_CONCURRENT_PER_CALLER, and METTLE_MCP_MAX_GLOBAL_CONCURRENT. Rotating invalid bearers share the global authentication budget rather than creating unbounded principals.

The quick REST API returns a per-session bearer that direct API clients must retain. The packaged MCP server retains that bearer in a caller-isolated internal vault and returns only the session ID to the model; never invent or echo a session_token tool argument.

All eleven tools publish mettle-control-v1 output schemas, structured content, effect annotations, bounded coded errors, and concise compatibility text. Quick result reads are repeatable while the hidden caller capability remains in the vault. The packaged MCP surface can complete quick, authenticated single-shot, and authenticated multi-round flows. Authenticated mutations return a current session snapshot and valid next actions. The larger unified agent contract and migration plan remain documented in Agent control plane.

API Reference

The authenticated suite API is mounted under /api/mettle:

GET  /suites

POST /sessions POST /sessions/{id}/verify POST /sessions/{id}/rounds/{n}/answer GET /sessions/{id}/result GET /sessions/{id}/result?include_vcp=true

The quick screening API remains under /api/session. Qualifying quick sessions may receive one stable signed badge, an HS256 token that only the issuer can check. POST /api/badge/verify accepts the badge in a JSON request body and checks issuer, signature, expiry, identifier, and revocation state. The badge is never accepted in a request URL.

VCP Metadata

Caller-supplied VCP strings are parsed as metadata only. Returned governance metadata always has:

"source_verified": false, "has_action_gate": false, "has_drift_detection": false, "has_bilateral": false, "attestation_signature": null }

Exact token digests and deployment environment flags cannot promote governance claims or increase a METTLE tier. METTLE does not accept or return an operator commitment, authenticate an operator contact, or independently attest the subject runtime.

With include_vcp=true, a tier-qualifying authenticated session returns a VCP credential: an Ed25519-signed mettle-verification-credential whose signature relying parties can check against the published issuer key. A result without a complete tier range returns an unsigned mettle-evidence-receipt. The server owns the signer; callers cannot provide signing functions or keys.

Local Development

git clone https://github.com/Creed-Space/METTLE.git

cd METTLE python -m venv .venv source .venv/bin/activate pip install -r requirements.txt pip install -r requirements-dev.txt

uvicorn main:app --reload pytest tests/ -v

Architecture, Assurance, and Operations

Documentation map and authority
System architecture
Agent control plane target design
Active agentic system roadmap
Assurance case
Security policy
Protocol governance and appeals
Credential transparency and key history
Privacy and retention
Compatibility fixtures and OpenAPI
Retry and idempotency contract
Error taxonomy
Deprecation policy
Independent review plan and dispositions
Operations runbooks
Release checklist

License

Apache License 2.0. See LICENSE.

Links

Built by Nell Watson and Creed Space.

Mettle MCP

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Tethered Trust

README from the maker

METTLE

Quick Start

Interactive local screening. Prints an unsigned local result;

signed badges and credentials come only from the server.

Twelve Experimental Suites

Credential Boundary

MCP Server

API Reference

VCP Metadata

Local Development

Architecture, Assurance, and Operations

License

Links