eval-harness

eval-harness is a skill for Claude Code, Codex from bcefghj/forks-collection. It costs 19 tokens per session (1,405 once invoked), scanned A, original, no licence file.

A framework for formally evaluating Claude Code sessions using eval-driven development, a method of guiding implementation by writing and checking evaluations.

In plain words
What is it for?
Use it to build or run evaluations for Claude Code implementation sessions.
Why use it?
It provides a structured way to judge whether an agent session produced the intended result.

Skill for Claude CodeCodex

Written for Claude Code and Codex: shipped in a Claude Code plugin, but also agents/openai.yaml present. Also seen: installed under .agents/ (shared by several agents).

Part of the everything-claude-code plugin — 50 skills, 64 commands, 30 agents, 6 MCP servers shipped together

Good fit Use it to build or run evaluations for Claude Code implementation sessions.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/bcefghj/forks-collection/eval-harness
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.

Any agent
npx skills add bcefghj/forks-collection --skill eval-harness
Clone the repo
git clone --depth 1 https://github.com/bcefghj/forks-collection

Made for: Claude Code, Codex.

Or install everything-claude-code, the plugin that ships this one along with the rest of its 50 skills, 64 commands, 30 agents, 6 MCP servers.

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 eval-harness

README.md
[![agentmods](https://agentmods.dev/badge/skills/bcefghj/forks-collection/eval-harness.svg)](https://agentmods.dev/skills/bcefghj/forks-collection/eval-harness)
Your own site
<a href="https://agentmods.dev/skills/bcefghj/forks-collection/eval-harness"><img src="https://agentmods.dev/badge/skills/bcefghj/forks-collection/eval-harness.svg" alt="Measured on agentmods" height="20"></a>
Per session 19 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,405 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00019 $0.01405
Opus 5 $0.00010 $0.00702
Sonnet 5 $0.00004 $0.00281
Haiku 4.5 $0.00002 $0.00140

Measured 8d ago against content hash 0bc29828b0b2, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-08, from the pricing page.

Security

Grade A, and why

eval-harness 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 8d ago.

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.

claude-code-forks/everything-claude-code/.agents/skills/eval-harness/SKILL.md · 237 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

1 file 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. 8d ago First seen · 237 lines · 19 tokens per session scan A 0bc29828b0b2

Subscribe to this mod's changes

eval-harness is a skill published in the GitHub repository bcefghj/forks-collection (5 stars, last pushed 5mo ago), with no licence file. It adds 19 tokens to every session and 1,405 once invoked, about $0.0001 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 2026-08-31.

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