skill-evolution-engine

skill-evolution-engine is a skill for Claude Code, Codex from Stijnman/grok-custom-skills. It costs 32 tokens per session (375 once invoked), scanned A, original, MIT.

A version-management tool for improving agent skills through backups, testing, reviewable changes, and approval.

In plain words
What is it for?
It helps save versions of instruction files, run baseline tests, compare proposed changes, report regressions, and preserve rollback options.
Why use it?
It helps track changes to a skill and catch quality regressions before an update is kept or published.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit It helps save versions of instruction files, run baseline tests, compare proposed changes, report regressions, and preserve rollback options.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/stijnman/grok-custom-skills/skill-evolution-engine
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 Stijnman/grok-custom-skills --skill skill-evolution-engine
Clone the repo
git clone --depth 1 https://github.com/Stijnman/grok-custom-skills

Made for: Claude Code, Codex.

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-evolution-engine

README.md
[![agentmods](https://agentmods.dev/badge/skills/stijnman/grok-custom-skills/skill-evolution-engine/github.svg)](https://agentmods.dev/skills/stijnman/grok-custom-skills/skill-evolution-engine)
Your own site
<a href="https://agentmods.dev/skills/stijnman/grok-custom-skills/skill-evolution-engine"><img src="https://agentmods.dev/badge/skills/stijnman/grok-custom-skills/skill-evolution-engine/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-evolution-engine

Your own site · 80×15
<a href="https://agentmods.dev/skills/stijnman/grok-custom-skills/skill-evolution-engine"><img src="https://agentmods.dev/badge/skills/stijnman/grok-custom-skills/skill-evolution-engine.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 32 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 375 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 $0.00032 $0.00375
Opus 5 $0.00016 $0.00187
Sonnet 5 $0.00006 $0.00075
Haiku 4.5 $0.00003 $0.00038

Measured 9d ago against content hash f24ad40156df, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

skill-evolution-engine 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.

.grok/skills/skill-evolution-engine/SKILL.md · 48 lines

What it actually says

Skill Evolution Engine

When to Use

  • User says evolve skills or task matches this capability
  • User says version skills or task matches this capability
  • User says skill maintenance or task matches this capability

Workflow

  1. Snapshot the current SKILL.md to a local versioned backup and run the hyper-skill-tester baseline.
  2. Prepare the proposed evolution as a reviewable diff with expected benefits, risks, and rollback path.
  3. Obtain explicit user approval before applying, committing, publishing, or otherwise persisting the proposed change.
  4. After approval, apply the change and compare scores. Present any regression and its rollback option for approval rather than rolling back automatically.

Integrations

  • skill-evolver
  • evolution
  • evolver
  • hyper-skill-tester

Error Handling

Failure Response
Score regression Preserve the evidence, present the latest backup and rollback diff, and wait for user approval before restoring.

Gotchas

  • Keep version backups locally; do not publish, delete, or restore them without explicit user approval.

Example

Input: User request matching triggers above. Output: Structured result per workflow with integrations invoked as needed.

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 · 48 lines · 32 tokens per session scan A f24ad40156df

Subscribe to this mod's changes

skill-evolution-engine is a skill published in the GitHub repository Stijnman/grok-custom-skills (9 stars, last pushed yesterday), licensed MIT. It adds 32 tokens to every session and 375 once invoked, about $0.0002 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 2026-09-03.

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