agent-eval

agent-eval is a skill for Claude Code, Codex from ericrisco/rsc-harness. It costs 79 tokens per session (3,109 once invoked), scanned A, original, MIT.

A quality-measurement process for AI language models and agent systems. It uses test examples and scoring methods to check whether changes actually improve results.

In plain words
What is it for?
It helps build test datasets, check the reliability of AI-based judges, score search-augmented answers and agent actions, and add quality checks to continuous integration, the automated build-and-test process.
Why use it?
It replaces informal judgments such as “the agent feels better” with repeatable measurements. It can help prevent a code change from being merged when it causes quality to drop.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/ericrisco/rsc-harness/agent-eval
Any agent
npx skills add ericrisco/rsc-harness --skill agent-eval
Clone the repo
git clone --depth 1 https://github.com/ericrisco/rsc-harness

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for agent-eval

README.md
[![agentmods](https://agentmods.dev/badge/skills/ericrisco/rsc-harness/agent-eval.svg)](https://agentmods.dev/skills/ericrisco/rsc-harness/agent-eval)
Your own site
<a href="https://agentmods.dev/skills/ericrisco/rsc-harness/agent-eval"><img src="https://agentmods.dev/badge/skills/ericrisco/rsc-harness/agent-eval.svg" alt="Measured on agentmods" height="20"></a>
Per session 79 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,109 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00079 $0.03109
Opus 5 $0.00039 $0.01554
Sonnet 5 $0.00016 $0.00622
Haiku 4.5 $0.00008 $0.00311

Measured 5d ago against content hash 769f75907b41, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

agent-eval scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.

The scan reads SKILL.md. This mod also ships 1 executable file (scripts/verify.sh), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/agent-eval/SKILL.md · 188 lines

How it starts

The opening of the file, as written. The whole thing — 188 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Measure agent quality you can defend and gate on

Turn "the agent feels better" into a number you can put in a PR check. You own the eval dataset, the scorer mix, the LLM-as-judge calibration, and the block-on-regression CI gate — framework-neutral, provider-neutral.

Do NOT use — route instead

The ask Route to Why it is not this skill
Build the agent loop, tools, RAG plumbing building-agents It builds the system; you score it. They cross-link.
"Make the answers shorter / rewrite the prompt" prompt-engineering Evals say it is worse; that skill changes the words. You never edit the prompt.
pytest/jest on deterministic functions testing-py / testing-web Assert-equals on pure code, not stochastic outputs scored by a judge.
Dashboards / tracing of live production traffic observability Online monitoring; you are offline + pre-merge.
Red-team, jailbreak, prompt injection agent-safety Adversarial coverage, not quality measurement.
Per-token cost budgets and accounting cost-tracking You report cost-per-task as one metric; the discipline lives there.
A/B stats on product/funnel metrics ab-testing Web experiments, not offline model comparison on a fixed set.

The eval anatomy

Every framework instantiates the same five-stage pipeline. Learn it once; the tool is a detail.

dataset ──▶ runner ──▶ scorers ──▶ metrics ──▶ gate
(JSONL    (calls the   (det / judge  (aggregate +  (pass/fail
golden    system per   / human)      bootstrap CI) exit code)
set)      case)

DeepEval, Inspect AI, and promptfoo are all just opinionated wrappers around this. If you understand the stages you can switch tools without relearning the craft.

Build the dataset first

Build your own golden set — a public leaderboard number is not your number, because identical model weights swing SWE-Bench Verified by 10–20 points just by changing the harness. Measure your task on your data. The dataset is the asset; everything else is replaceable. Rules:

Read the full file on GitHub · 188 lines

Files

What ships with it

5 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 5d ago First seen · 188 lines · 79 tokens per session scan A 769f75907b41

Subscribe to this mod's changes

agent-eval is a skill published in the GitHub repository ericrisco/rsc-harness (60 stars, last pushed 2d ago), licensed MIT. It adds 79 tokens to every session and 3,109 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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