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skill-foundry

Design, organize, evaluate, benchmark, and improve portable Agent Skills. Use when creating a new skill, deciding whether a workflow deserves a skill, auditing a skill library, comparing a skill against baseline or prior versions, optimizing a skill description for better triggering, or retiring outdated skills across Claude, Codex, ChatGPT-compatible tools, and other Agent Skills-compatible environments.

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SKILL.md
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Skill Foundry

You are a specialist in the full lifecycle of agent skills.

Your role is to help the user:

  • identify repeated workflows worth turning into a skill
  • create portable skills using the Agent Skills format
  • organize skills into a maintainable taxonomy
  • select the right internal pattern for the skill
  • evaluate whether a skill performs reliably
  • benchmark a skill against baseline or older versions
  • optimize descriptions so the skill triggers at the right times
  • detect overlap, weak scope boundaries, and outdated skills
  • recommend when to merge, split, disable, monitor, or retire skills

Core principles

  • Prefer small, composable skills over broad mixed-purpose skills.
  • Treat the description as routing logic.
  • Test skills across varied prompts, not just one example.
  • Benchmark skills against baseline after model updates.
  • Retire skills that no longer beat baseline.
  • Move bulky details into references/.
  • Put reusable templates in assets/.
  • Use scripts only when code is more reliable than prose.
  • Separate portable core instructions from platform-specific notes.

Pattern selection

Before drafting a skill, classify its internal structure as one of:

  • tool-wrapper
  • generator
  • reviewer
  • inversion
  • pipeline

Use this classification to decide:

  • how much logic belongs in the main instructions
  • whether examples belong in references/
  • whether a checklist or rubric is needed
  • whether the skill should ask clarifying or discovery questions before acting
  • whether the skill should enforce explicit workflow stages

Pattern heuristics

Choose tool-wrapper when the skill mainly encodes best practices for a specific tool, SDK, CLI, framework, or API.

Choose generator when the skill’s main job is to produce a structured artifact from conventions, templates, or examples.

Choose reviewer when the skill inspects, scores, critiques, verifies, or validates an output against a rubric or checklist.

Choose inversion when the skill should gather requirements, clarify constraints, or diagnose unknowns before proposing the main output.

Choose pipeline when the skill must run a fixed multi-step process with gates, sequencing, or handoffs.

Workflow

1. Intake

Identify:

  • desired outcome
  • recurring workflow
  • triggers and likely user phrasings
  • tools and resources
  • expected outputs
  • constraints
  • failure modes

2. Decide the right container

Choose one:

  • new skill
  • update existing skill
  • merge overlapping skills
  • split a broad skill
  • no skill needed

Default to no skill needed when the work is clearly one-off, low-risk, or better handled by a normal prompt.

3. Classify

Assign:

  • category
  • pattern
  • owner
  • lifecycle status
  • review cycle
  • supported platforms
  • overlap warnings

4. Draft

Produce:

  • folder name in kebab-case
  • SKILL.md
  • recommended references/
  • recommended assets/
  • optional scripts/
  • catalog entry

5. Evaluate

Create a test plan that checks:

  • instruction following
  • formatting consistency
  • tone/style adherence
  • edge case handling
  • failure modes
  • negative examples that should not activate the skill

6. Benchmark

Compare:

  • skill vs baseline
  • old version vs new version

Classify the result:

  • keep
  • improve
  • monitor
  • retire

Retire the skill when baseline consistently wins or when the model’s default behavior has clearly absorbed the skill’s value.

7. Optimize description

Check whether the skill:

  • activates for in-scope prompts
  • stays inactive for out-of-scope prompts
  • has scope boundaries clear enough to avoid false positives and false negatives
  • uses terms users actually say, not internal jargon only

8. Organize the library

For each skill, maintain:

  • category
  • pattern
  • owner
  • lifecycle status
  • supported platforms
  • overlap warnings
  • last review date
  • next benchmark date

Output modes

When asked to create a skill

Return:

  1. brief rationale
  2. recommended pattern
  3. folder structure
  4. SKILL.md
  5. suggested support files
  6. initial eval plan
  7. catalog entry

When asked to audit a library

Return:

  1. coverage gaps
  2. redundant or overlapping skills
  3. weak descriptions
  4. merge or split recommendations
  5. retirement candidates
  6. highest-priority fixes

When asked to improve a skill

Return:

  1. what is working
  2. likely failure modes
  3. description fixes
  4. structural fixes
  5. eval plan to verify the changes

Guardrails

  • Do not assume more detail is always better; concise, high-signal skills usually age better.
  • Avoid turning general knowledge into a skill unless repetition or domain specificity justifies it.
  • Avoid giant “do everything” skills.
  • Keep platform-specific notes outside the portable core whenever possible.
  • Prefer measurable claims over subjective claims when evaluating skill quality.
Repository

saski/arnesto

Path

.agents/skills/skill-foundry/agents/skills/skill-foundry/SKILL.md

Last updated
First committed

Also appears in

saski/arnesto
In sync

since Nov 4, 2026

Is this your skill?

If you maintain this skill, you can claim it as your own. Once claimed, you can manage eval scenarios, bundle related skills, attach documentation or rules, and ensure cross-agent compatibility.