Evals

Evals is a skill for Claude Code, Codex from fr3kstyle/fr3k. It costs 63 tokens per session (1,828 once invoked), scanned A, original, no licence file.

A framework for testing AI agents against expected behavior. It supports code-based, model-based, and human grading, records conversation transcripts, and reports pass@k and pass^k results, which measure repeated-task success.

In plain words
What is it for?
Evaluating agent capabilities, benchmarking behavior, testing tasks, and reviewing evaluation transcripts.
Why use it?
It helps detect regressions and verify that an agent still behaves correctly after changes.

Skill for Claude CodeCodex

Which agent this was written for is unclear — body not stored (licence); the path alone says nothing.

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/fr3kstyle/fr3k/evals
Any agent
npx skills add fr3kstyle/fr3k --skill evals
Clone the repo
git clone --depth 1 https://github.com/fr3kstyle/fr3k

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 Evals

README.md
[![agentmods](https://agentmods.dev/badge/skills/fr3kstyle/fr3k/evals.svg)](https://agentmods.dev/skills/fr3kstyle/fr3k/evals)
Your own site
<a href="https://agentmods.dev/skills/fr3kstyle/fr3k/evals"><img src="https://agentmods.dev/badge/skills/fr3kstyle/fr3k/evals.svg" alt="Measured on agentmods" height="20"></a>
Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,828 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin unknown 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 5.1 $0.00063 $0.01828
Opus 5 $0.00032 $0.00914
Sonnet 5 $0.00013 $0.00366
Haiku 4.5 $0.00006 $0.00183

Measured 6d ago against content hash ab3c9b76fbfb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

Evals scanned grade A with 1 finding 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 6d ago.

The scan reads SKILL.md. This mod also ships 19 executable files (Graders/Base.ts, Graders/CodeBased/BinaryTests.ts, Graders/CodeBased/index.ts, …), 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -s -X POST http://localhost:8888/notify \
claude-skills/Evals/SKILL.md · 232 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

49 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. 6d ago First seen · 232 lines · 63 tokens per session scan A ab3c9b76fbfb

Subscribe to this mod's changes

Evals is a skill published in the GitHub repository fr3kstyle/fr3k (2 stars, last pushed 6mo ago), with no licence file. It adds 63 tokens to every session and 1,828 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.