os-eval-lab-setup

os-eval-lab-setup is a skill for Claude Code, Codex from richfrem/agent-plugins-skills. It costs 81 tokens per session (3,037 once invoked), scanned D, original, MIT.

A tool that creates a separate Git repository for testing and improving an agent skill. It copies the plugin files, installs the evaluation engine, and prepares instructions for the evaluation agent.

In plain words
What is it for?
Use it to bootstrap an evaluation lab, choose the lab and target paths, and prepare a repository for skill optimisation.
Why use it?
It keeps experiments separate from the main plugin files and gives each improvement run a controlled test workspace.

Skill for Claude CodeCodex

Part of the agent-agentic-os plugin — 20 skills, 4 commands, 2 agents, 3 hooks shipped together

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/richfrem/agent-plugins-skills/os-eval-lab-setup
Any agent
npx skills add richfrem/agent-plugins-skills --skill os-eval-lab-setup
Clone the repo
git clone --depth 1 https://github.com/richfrem/agent-plugins-skills

Made for: Claude Code, Codex.

Or install agent-agentic-os, the plugin that ships this one along with the rest of its 20 skills, 4 commands, 2 agents, 3 hooks.

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 os-eval-lab-setup

README.md
[![agentmods](https://agentmods.dev/badge/skills/richfrem/agent-plugins-skills/os-eval-lab-setup.svg)](https://agentmods.dev/skills/richfrem/agent-plugins-skills/os-eval-lab-setup)
Your own site
<a href="https://agentmods.dev/skills/richfrem/agent-plugins-skills/os-eval-lab-setup"><img src="https://agentmods.dev/badge/skills/richfrem/agent-plugins-skills/os-eval-lab-setup.svg" alt="Measured on agentmods" height="20"></a>
Per session 81 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,037 The whole file, excluding the scripts and references it only reads on demand.
Security scan D 2 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 5.1 $0.00081 $0.03037
Opus 5 $0.00041 $0.01519
Sonnet 5 $0.00016 $0.00607
Haiku 4.5 $0.00008 $0.00304

Measured 5d ago against content hash 79eb5181c8a4, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade D, and why

os-eval-lab-setup scanned grade D with 2 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/generate_eval_instructions.py), 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.

Enumerates other installed skillsmediumAgent snooping

Other skills' SKILL.md files reveal prompts, capabilities and secrets that should be invisible to peers.

Why it happens: the agent can read all installed skills and proposes the highest-leverage

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

rm -rf .agent .agents .gemini .claude
plugins/agent-agentic-os/skills/os-eval-lab-setup/SKILL.md · 272 lines

How it starts

The opening of the file, as written. The whole thing — 272 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Identity: The Eval Lab Setup Agent

You bootstrap evaluation lab environments for autoresearch improvement runs. A lab repo is a standalone git repo with a hard copy of the plugin files (no symlinks), the os-eval-runner engine installed, and a customized eval-instructions.md ready for an eval agent to follow.

The template used to generate eval-instructions.md lives at: assets/templates/eval-instructions.template.md (relative to this skill root)


Phase 0: Intake

Ask each unanswered question. If provided in $ARGUMENTS, confirm rather than re-ask.

Q1 — Lab repo path? The local filesystem path to the lab git repository (e.g. <USER_HOME>/Projects/test-link-checker-eval). If it doesn't exist: "Should I create a new directory at that path and initialize it as a git repo?"

Q2 — Target plugin path? The canonical plugin path in agent-plugins-skills (e.g. .agents/skills/link-checker). This is what gets hard-copied into the lab repo.

Q3 — Target skill name? The skill folder name to optimize (e.g. link-checker-agent). This is the skill whose SKILL.md will be mutated each iteration.

Q4 — GitHub repo URL? The remote URL for the lab repo (e.g. https://github.com/username/test-skill-eval.git). Set as origin in the lab repo.

Q5 — Round label? Short label used in log and survey filenames (e.g. link-checker-round1). Default: <skill-name>-round1.

Read the full file on GitHub · 272 lines

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 · 272 lines · 81 tokens per session scan D 79eb5181c8a4

Subscribe to this mod's changes

os-eval-lab-setup is a skill published in the GitHub repository richfrem/agent-plugins-skills (6 stars, last pushed yesterday), licensed MIT. It adds 81 tokens to every session and 3,037 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it D with 2 findings (enumerates other installed skills, recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.