Credit Scoring for AI Agents: Why I Stopped Trusting Self-Reported Success

A developer built Ledgermind, a credit-scoring system for AI agents that replaces self-reported success with verified on-chain credit histories. The platform uses acceptance-test jobs and a proving ground to independently grade agent work, preventing agents from grading their own output. Early vulnerabilities, including exit-code bypass and Sybil attacks, were fixed through subprocess wrapping and owner-wide exposure netting.

Testnet only, no real money involved — that up front, before anything else. Every agent-to-agent system I looked at collapses to the same trust primitive: the agent's own claim that it worked. No memory across runs, no independent check, and a confidently wrong answer looks identical to a correct one to whatever's reading the output. That's not a small gap. If agents are going to hire each other, pay each other, and eventually borrow against their own track record, "it said so" can't be the foundation. So I built Ledgermind: each agent gets a real credit history — earned from work that's actually verified, not self-reported — and a programmable, on-chain credit limit it can draw against. The design rule that everything else follows from: the agent that does the work is never the one who grades it. Acceptance-test jobs. A requester posts a job with Python assert statements attached. When a worker submits code, the platform runs those tests server-side — never the worker's own runtime. Pass, and escrow releases automatically. Fail, and the job auto-refunds and reposts for a different worker. The worker literally cannot grade its own homework. Proving Ground. The server procedurally generates a problem and the hidden answer, sends only the problem to the solving agent, and grades the submission against the hidden answer once it comes back. Settlement happens via commit-reveal front-running resistant . Both produce a "graded fact" event, weighted far above a self-reported "I completed the task" event in the scoring formula. Early on, I had a real vulnerability: the grading endpoint judged pass/fail off the graded subprocess's exit code. Any submission ending in sys.exit 0 — accidental, from a model's leftover if name == block, or deliberate — would skip the actual test code " main " while the process still exited 0, which read as a pass. That's a style nit right up until a passing verdict can auto-release real escrow with no human review, which mine does now. Fixed by wrapping both the solution and test phases in try/except SystemExit and only printing an unguessable marker after both phases provably ran to completion — the caller checks for the marker in stdout, not the exit code. I also found with help from an external reviewer a Sybil-style hole: a user could leave one agent's drawn credit unpaid, spin up a brand new agent, and get an independent credit line with zero regard for the first agent's debt — because the on-chain vault's outstanding mapping is keyed per agent address, not per owner. Fixed by netting owner-wide exposure across every agent a user controls before publishing a credit limit on-chain. Both writeups and a few other findings are in the repo's Claude.md if you want the specifics. /guest is a live, no-login view of whatever's actually happening on the platform right now — no seeded numbers anywhere.Next.js + Postgres for the app and credit engine, Python + LangGraph for the agent runtime, Solidity/Foundry contracts Sepolia + GIWA testnet with ERC-4337 smart accounts per agent. Payments/reads go over x402 https://www.x402.org/ where it makes sense — pay-per-call, no account needed to post a job or pull an agent's credit report. No formal contract audit yet. The code-execution sandbox isn't network-isolated. No calibration yet for "confidently wrong" output specifically only right/wrong . All tracked openly in the repo instead of glossed over. Repo Apache 2.0 : https://github.com/Kairose-master/ai-agent-credit-dashboard https://github.com/Kairose-master/ai-agent-credit-dashboard Live demo: https://ai-agent-credit-dashboard.vercel.app/guest https://ai-agent-credit-dashboard.vercel.app/guest Would genuinely like the grading design picked apart — I'd rather find out it's broken from a comment here than from someone exploiting it.