skill-evaluator

skill-evaluator is a skill for Claude Code, Codex from HeshamFS/materials-simulation-skills. It costs 181 tokens per session (3,166 once invoked), scanned A, original, Apache-2.0.

A testing system for agent skills, which are instruction packages that guide coding agents. It checks whether scripts work, descriptions trigger on suitable requests, and the instructions improve results compared with using no skill.

In plain words
What is it for?
Running deterministic script checks, testing when a skill activates, and comparing an agent's results with and without the skill.
Why use it?
It separates a skill that merely looks correct from one that is discoverable, produces the promised results, and actually helps an agent.

Skill for Claude CodeCodex

Written for Claude Code and Codex: allowed-tools in frontmatter, but also runs codex exec. Also seen: mentions Claude Code; mentions Codex; mentions Gemini CLI.

Good fit Running deterministic script checks, testing when a skill activates, and comparing an agent's results with and without the skill.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/heshamfs/materials-simulation-skills/skill-evaluator
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 HeshamFS/materials-simulation-skills --skill skill-evaluator
Clone the repo
git clone --depth 1 https://github.com/HeshamFS/materials-simulation-skills

Made for: Claude Code, Codex.

Its marketplace also offers this one on its own, as the plugin meta/plugin install meta after adding the marketplace above.

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-evaluator

README.md
[![agentmods](https://agentmods.dev/badge/skills/heshamfs/materials-simulation-skills/skill-evaluator.svg)](https://agentmods.dev/skills/heshamfs/materials-simulation-skills/skill-evaluator)
Your own site
<a href="https://agentmods.dev/skills/heshamfs/materials-simulation-skills/skill-evaluator"><img src="https://agentmods.dev/badge/skills/heshamfs/materials-simulation-skills/skill-evaluator.svg" alt="Measured on agentmods" height="20"></a>
Per session 181 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,166 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 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 $0.00181 $0.03166
Opus 5 $0.00090 $0.01583
Sonnet 5 $0.00036 $0.00633
Haiku 4.5 $0.00018 $0.00317

Measured 8d ago against content hash 3464a5c93a0e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

skill-evaluator 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.

The scan reads SKILL.md. This mod also ships 6 executable files (eval-viewer/generate_review.py, scripts/agent_adapters.py, scripts/aggregate_benchmark.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.

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.

skills/meta/skill-evaluator/SKILL.md · 227 lines

How it starts

The opening of the file, as written. The whole thing — 227 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill Evaluator

Test whether a skill is correct, discoverable, and valuable — not just whether its unit tests pass. The harness is agent-agnostic: it drives whichever coding-agent CLI the user uses, because Agent Skills are portable across all of them.

When to use which layer

Three layers, increasing cost and fidelity (full rationale in references/methodology.md):

Layer Question Script Needs a CLI?
1. Deterministic Do the scripts emit the documented numbers? run_script_checks.py No
2. Trigger Does the description activate on the right prompts? run_trigger_eval.py Yes
3. Quality Does following the SKILL.md beat no skill? run_quality_eval.py → grade → aggregate_benchmark.py Yes

Always run Layer 1 (it's free). Add Layers 2–3 when you can run a coding-agent CLI.

Step 0 — pick the agent CLI

Ask the user which coding agent they use, then map it to an adapter id. Supported: claude-code, openai-codex, antigravity (the agy CLI that replaced Gemini CLI on 2026-06-18), cursor-cli, github-copilot-cli, amp, opencode, grok-cli. See the full matrix and auth in references/adapters.md, or run:

python scripts/agent_adapters.py list

Confirm the binary is installed and the auth env var is set (the matrix lists it). Before any real run, dry-run it to see the exact command:

python scripts/agent_adapters.py build <agent> --prompt "test" --workdir /tmp/wd

Step 1 — deterministic script checks (always)

python scripts/run_script_checks.py --skill <path-to-skill> --json

Runs the script_checks in the skill's evals/evals.json, executing each script and grading its --json output against machine-checkable assertions. Exit non-zero on any failure — safe for CI. If the skill has few/no script_checks, add them for every eval whose answer is computable (schema in references/schemas.md); this is the cheapest, most durable guard against doc↔code drift.

Read the full file on GitHub · 227 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. 8d ago First seen · 227 lines · 181 tokens per session scan A 3464a5c93a0e

Subscribe to this mod's changes

skill-evaluator is a skill published in the GitHub repository HeshamFS/materials-simulation-skills (66 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 181 tokens to every session and 3,166 once invoked, about $0.0009 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 2026-08-30.