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Os Eval Runner

Category: Science & Research  ·  Sub-category: science-misc  ·  Last updated:
lang:python
Stateless evaluation engine that scores and gates skill improvement iterations using headless Python evaluation scripts. Use when the user says "evaluate this skill", "run autoresearch loop on", "optimize this skill", "run the eval loop", or when another agent proposes a change to an existing skill and needs empirical validation before applying it. Supports autonomous loop mode for iterative improvement and single-shot QA mode for validating one specific proposed change. Requires Python 3.8+ and a git repository.
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From the source SKILL.md

<example> <commentary>Start autonomous improvement loop on a skill.</commentary> user: "Run the autoresearch loop on plugins/link-checker/skills/link-checker-agent for 20 iterations" assistant: [triggers os-eval-runner, runs Mode 1 intake, establishes baseline, begins iteration loop] </example>

What this skill does

Os Eval Runner is a community-contributed Claude Code skill in the science-misc sub-category. It ships as a SKILL.md file that Claude Code auto-discovers under ~/.claude/skills/os-eval-runner/ and loads when your prompt matches the skill's trigger.

When to invoke it: Use when the user says "evaluate this skill", "run autoresearch loop on", "optimize this skill", "run the eval loop", or when another agent proposes a change to an existing skill and needs empirical validation before applying it. Supports autonomous loop mode for iterative improvement and single-shot QA mode for validating one specific proposed change.

Who uses this skill

The Os Eval Runner Claude Code skill is built for researchers, data scientists, academics, and analysts working with complex data and scientific literature. It's part of ClaudSkills (also referred to as Claude Skills or Claude Code Skills) — the open community-curated registry of 146,000+ SKILL.md files for Anthropic's Claude Code agent and the wider Claude ecosystem (Claude API, Claude Agent SDK).

How to install

Free

Manual install (2 steps)

mkdir -p ~/.claude/skills/os-eval-runner
curl -L https://claudskills.com/skills/os-eval-runner/SKILL.md \
  -o ~/.claude/skills/os-eval-runner/SKILL.md

Or just download SKILL.md directly and drop it into ~/.claude/skills/os-eval-runner/. Claude Code auto-discovers it on next session.

Skills live at ~/.claude/skills/os-eval-runner/SKILL.md on macOS/Linux, or %USERPROFILE%\.claude\skills\os-eval-runner\SKILL.md on Windows. See the full install guide for step-by-step instructions.

Telegram

📱 Install from your phone or desktop Telegram

Open @claudskills_bot on Telegram, tap Open Desktop App, and the desktop app installs this skill for you. Or share the bot link with a colleague — they get the same one-tap install. Learn more →

Pro

One-click install via the desktop app

The ClaudSkills desktop app installs any skill directly into ~/.claude/skills/ with one click — no terminal required. Pro starts at $9/mo or $149 lifetime.

Pro

For the full experience including quality scoring and one-click install features for each skill — upgrade to Pro.

See pricing → Download desktop app

Frequently asked questions

How do I install the Os Eval Runner Claude Code skill?
Install via the ClaudSkills desktop app (one click) or copy SKILL.md from the source repository to ~/.claude/skills/os-eval-runner/SKILL.md and restart Claude Code. Both flows are detailed at claudskills.com/install/.
What does the Os Eval Runner skill do?
Stateless evaluation engine that scores and gates skill improvement iterations using headless Python evaluation scripts. Use when the user says "evaluate this skill", "run autoresearch loop on", "optimize this skill", "run the eval loop", or when another agent proposes a change to an existing skill and needs empirical validation before applying it. Supports autonomous loop mode for iterative improvement and single-shot QA mode for validating one specific proposed change. Requires Python 3.8+ and a git repository.
Is this skill free to install?
Yes. ClaudSkills is an open registry — every skill keeps its source repository's license, and manual install via copy is free. ClaudSkills Pro ($9/mo, $79/yr, or $149 one-time) adds one-click install via the desktop app and a multi-signal Quality Score.
When should I use the Os Eval Runner skill?
Use Os Eval Runner when your Claude Code task falls under the Science & Research category — specifically in the science misc area. Claude Code auto-discovers installed skills and invokes the right one based on the task description, so you can also ask Claude directly (e.g. "use Os Eval Runner" or describe the task and let Claude pick). Browse related skills at /category/science/.
What is a Claude Code skill and how does the Os Eval Runner skill fit in?
A Claude Code skill is a SKILL.md file that lives under ~/.claude/skills/<name>/ and tells the Claude Code CLI agent how to perform a specific task (instructions, prompts, allowed tools). Skills are auto-discovered at session start. Os Eval Runner is one of 67,000+ skills indexed in the open ClaudSkills catalog, classified under the Science & Research category. Learn more at /learn/what-is-a-claude-skill/.

Attribution & license

Cite this skill

If you reference this skill in a blog post, paper, or documentation, you can cite it as:

APA
richfrem. (2026). Os Eval Runner [Claude Code skill]. ClaudSkills. https://claudskills.com/skills/os-eval-runner/
BibTeX
@misc{os-eval-runner-2026,
  author    = {richfrem},
  title     = {Os Eval Runner [Claude Code skill]},
  year      = {2026},
  publisher = {ClaudSkills},
  url       = {https://claudskills.com/skills/os-eval-runner/}
}

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More Science & Research skills

Browse all Science & Research skills in the ClaudSkills registry, or explore these other picks from the same category:

Browse all Science & Research skills → Top 100 skills
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