skill-eval-improve

skill-eval-improve is a skill for Claude Code, Codex from Arenukvern/skill_steward. It costs 61 tokens per session (2,411 once invoked), scanned A, a copy of skill-eval-improve, MIT.

A measured workflow for improving an existing Agent Skill by validating it, testing example cases, making limited edits, and checking results again.

In plain words
What is it for?
Use it to tune skill descriptions and procedures, run validation and evaluations, compare changes with a baseline, and improve quality within bounded edits.
Why use it?
It helps fix weak triggering, excessive instructions, or poor outcomes while guarding against regressions.

Skill for Claude CodeCodex

Written for Claude Code and Codex: paths in frontmatter, but also reads ~/.codex or $CODEX_HOME. Also seen: mentions Codex.

Part of the skill-steward plugin — 15 skills shipped together

Good fit Use it to tune skill descriptions and procedures, run validation and evaluations, compare changes with a baseline, and improve quality within bounded edits.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/arenukvern/skill_steward/skill-eval-improve
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 Arenukvern/skill_steward --skill skill-eval-improve
Clone the repo
git clone --depth 1 https://github.com/Arenukvern/skill_steward

Made for: Claude Code, Codex.

Or install skill-steward, the plugin that ships this one along with the rest of its 15 skills.

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 skill-eval-improve

README.md
[![agentmods](https://agentmods.dev/badge/skills/arenukvern/skill_steward/skill-eval-improve/github.svg)](https://agentmods.dev/skills/arenukvern/skill_steward/skill-eval-improve)
Your own site
<a href="https://agentmods.dev/skills/arenukvern/skill_steward/skill-eval-improve"><img src="https://agentmods.dev/badge/skills/arenukvern/skill_steward/skill-eval-improve/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for skill-eval-improve

Your own site · 80×15
<a href="https://agentmods.dev/skills/arenukvern/skill_steward/skill-eval-improve"><img src="https://agentmods.dev/badge/skills/arenukvern/skill_steward/skill-eval-improve.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 61 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,411 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 100% copy Near-identical to another mod 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 $0.00061 $0.02411
Opus 5 $0.00030 $0.01205
Sonnet 5 $0.00012 $0.00482
Haiku 4.5 $0.00006 $0.00241

Measured 9d ago against content hash 95275b22371b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

skill-eval-improve 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 9d 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.

Origin

This is a copy

100% identical to skill-eval-improve — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/skill-eval-improve/SKILL.md · 203 lines

How it starts

The opening of the file, as written. The whole thing — 203 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill eval & improve

Improve skills measurably: baseline → measure → bounded edit → re-validate. Combine local tooling, Codex plugin-eval (when installed), and research-backed loops (SkillOpt).

When to use

  • Skill triggers wrong or never loads (description routing)
  • Bloated SKILL.md, high token cost, weak outcomes
  • After adding a new procedure—need regression checks
  • Porting patterns from product MCP / plugin-eval research into Skill Steward skills

When not to use

  • Bulk repo validation — e.g. “validate every skill in this repo” → pnpm run validate only (skill-authoring-lifecycle for audit); do not start benchmark or SkillOpt loops.
  • Automated SkillOpt / cluster training — Skill Steward documents a manual bounded-edit loop; no overnight optimizer pipeline.
  • Creating a new skill — use skill-authoring-lifecycle first; eval-improve applies after a skill exists.

Cursor scope (optional): activate when editing under skills/** or scripts/validate-skills.mjs.

Mixture of experts (evaluation stack)

Layer Expert Tool / method Cost
0 — Gate Lint pnpm run validate, skill-authoring-lifecycle seconds
0b — Rules Routing/docs SSOT pnpm run eval (T1 behavior-critical YAML cases) seconds
1 — Static Structure Codex plugin-eval analyze (if available) seconds
2 — Human Behavior 3–5 prompts with/without skill minutes
3 — Measured Usage plugin-eval benchmark + measurement-plan minutes–hours
4 — Evolve Text optimization SkillOpt-style bounded edits + held-out gate hours
5 — Navigate Telemetry / dogfood Current steward benchmark scenarios on compact traces seconds

Use the cheapest layer that answers the question. Do not skip layer 0.

Layer 0 — Skill Steward validator (always)

Read the full file on GitHub · 203 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. 9d ago First seen · 203 lines · 61 tokens per session scan A 95275b22371b

Subscribe to this mod's changes

skill-eval-improve is a skill published in the GitHub repository Arenukvern/skill_steward (11 stars, last pushed 24d ago), licensed MIT. It adds 61 tokens to every session and 2,411 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to skill-eval-improve, differing in 0 lines, and is treated as a copy.

Related

Other skills, from other repositories

testing-patterns

Plan, write, and maintain automated tests in any language, with worked examples in Python and JavaScript/TypeScript. Use this skill whenever the user wants to write or plan tests, apply TDD (red-green-refactor), structure unit tests with arrange-act-assert and given-when-then naming, choose between fakes, stubs, and…

svngoku/coding-agents-skills · 184 tokens

bruno-api-testing

Create, run, and maintain API test collections using Bruno (OpenCollection YAML format and legacy Bru format). Use when the user wants to: (1) create a Bruno API test collection from scratch or from OpenAPI/Swagger specs, (2) write API request files with tests and assertions, (3) run API tests using bru CLI, (4)…

jim60105/copilot-prompt · 186 tokens

openspec-verify-change

Verify implementation matches change artifacts. Use when the user wants to validate that implementation is complete, correct, and coherent before archiving.

jim60105/copilot-prompt · 32 tokens

zsh-script-writer

Write and test Zsh scripts following project coding standards with ShellSpec BDD testing. Use when the user wants to: (1) create a new Zsh script, (2) write or fix ShellSpec tests for Zsh scripts, (3) review Zsh code for best practices, (4) add error handling or dependency checking to shell scripts, (5) implement API…

jim60105/copilot-prompt · 122 tokens

Test Engineer

Creates or completes a medium-coverage test suite: unit, component, and critical e2e flows.

Tariux/AI-Skills-Not-Awesome · 24 tokens

convex-verify

Prove a Convex feature works — seed, drive as multiple mocked users via convex-test, assert behavior including the negative authz cases (wrong user refused, data-scope enforced).

openclaw/clawhub · 42 tokens