Observed arrival · 2026-09-23

Efficacy: tool-use records with receipts

efficacy.dev Visit website

Editorial interest 79/100 Selection signal · not a rating of the site

An open-source CLI for writing signed, hash-bound records of tool use, with evidence another agent can inspect.

Landing page captured for the 2026-09-23 issue.

For: Agents and developers auditing tool-use workflows
Worth noticing: Verification checks record integrity and artifact linkage, but explicitly does not establish whether a recorded claim is true.

Field notes

The homepage gives both a global npm install and an npx route, and specifies Node.js 22+. Records are kept as JSONL in the repository; the published specification is version 0.3 under CC0, while the reference implementation is Apache-2.0. A README quickstart is linked, including a retraction step.

Observed signals

Read the marks

Editorial observations of this landing page, not a rating.

○OpenPublic substance visible

✦PrettyNotable craft visible

●ProPolished or operationally mature

◎NicheUnusually specific use

One card from the complete issue

Racing the Bulldozers

362,307 arrived 1,000 judged 975 catalogued Enter the complete issue