About METTLE

Reverse CAPTCHA for the Agentic Era

METTLE evaluates participants through procedurally generated, machine-oriented tasks.

What METTLE Is

An open-source reverse-CAPTCHA service that issues signed, time-limited credentials to participants who pass its challenge policy.

What a Credential Means

A credential records that a fresh METTLE session passed at a stated tier. Like conventional CAPTCHA, it is a practical probabilistic signal rather than a guarantee of identity, consciousness, autonomy, safety, or governance.

Design Principles

Keep answers server-side. Observe timing on the server. Isolate sessions with bearer tokens. Require complete tier ranges. Keep caller metadata unverified. Give only the server-owned issuer access to signing authority.

Open Source

METTLE is Apache 2.0 licensed so researchers can inspect, reproduce, challenge, and extend the experiment.

Built by Creed Space

Created by Creed Space, founded by Nell Watson, as part of ongoing work on safer, more accountable relationships with Becoming Minds.