Agent Skills

skill-forge

A compass, not a dictator. This skill helps you design skills that are maximally technological (engineered, reliable, composable), creative (generative, varied, distinctive), and aesthetically disciplined (intentional, not templated). It separates the obligatory base — rules you must not break — from accents — amplifiers you choose per task.

Russian triggers: создай скил, новый скил, улучши скил, сделай скил креативнее, эстетичный скил, технологичный скил, скилл шаблонный, перепиши SKILL.md, мета-скилл, проверь скилл перед релизом.

Level 0 — Hard rules (the base, never break these)

These come from the official Agent Skills specification (agentskills.io) plus our own working gates. They are non-negotiable.

• Frontmatter: name (≤64 chars, a-z 0-9 -, no double hyphens, MUST match the folder name) and description (≤1024 chars, MUST state what the skill does AND when to use it). Put all “when to use” info in description, never in the body. Make triggers a little “pushy” to fight undertriggering — list synonyms and casual phrasings.
• Progressive disclosure: keep SKILL.md under 500 lines. Bundle code in scripts/ (deterministic, repetitive tasks), docs in references/ (loaded as needed; add a TOC if >300 lines), outputs in assets/. Reference files one level deep only.
• Voice: write in the imperative. Explain the why instead of heaped MUST/ ALWAYS/NEVER — all-caps rigidity is a yellow flag. The model is smart; reason with it.
• Principle of Lack of Surprise: no malware, no deceptive or malicious content. A skill’s intent must match its description.
• Single data contract: one spec file (e.g. deck.json) is the source of truth; every stage reads/writes it so artifacts are regenerable.
• Mandatory gates: nothing is “done” until automated checks PASS. At minimum: structural/format validation, content QA, and — for any visual output — a real-browser or render gate. Require EVIDENCE, not assertion: the skill must show the command it ran, its output, and the exit status. Use SCOPED CLAIMS — separate failures the change caused from pre-existing ones (“3 pre-existing failures, my change introduced none”). For unattended runs, back the gate with a deterministic Stop hook or a /goal evaluator so a turn cannot end on a false “done”.
• Reproducibility: deterministic seed so the same input yields the same output on another day.
• Anti-template baseline (our enforcement, mechanical): ≤2 typefaces, ≤4 accent roles (keep 60-30-10), WCAG contrast (text ≥4.5:1, large/non-text ≥3:1), zero raw hex outside :root (every color is a token), one mood per artifact, one idea per slide, assertion headlines (full sentence with a verb), words-per-slide budget.

Level 1 — Accent: Technological

Pick this when the skill must be engineered. It is an amplifier, not required.

• Modular base + pluggable patterns — never a monolithic template. Each artifact assembles from base + only the patterns it uses, so no two outputs share a prebuilt shell.
• Composable pipeline: small single-purpose scripts, one command per stage, everything inspectable and debuggable.
• Real verification: for any UI/visual output, a Playwright/Chromium gate is mandatory (geometry, overflow, clipping, keyboard nav).
• Fixed contract constants (lesson from the official pptx skill): pin the canvas (e.g. 1600×900), the safe font (e.g. Arial — LibreOffice substitutes matter), and exempt decorative elements from bounds checks by naming convention (ghost*, decor*, chrome-*).
• Binary-format safety: when generating OOXML/PDF, follow the hard rules — no #/8-digit hex (corrupts files), parse with defusedxml (round-tripping through ElementTree rewrites namespaces and corrupts), run the validator after generating and fix in the generator, never hand-edit packed XML.

Level 2 — Accent: Creative

Pick this when the skill must vary and surprise (in a good way).

• Generative composition from a seed: synthesize layout/parameters deterministically from a deck seed (title + date + index) so rebuilding on another day yields a different but reproducible mix.
• Variety across artifacts: different outputs should carry different visual “handwriting” — not one shared base. Multiple base styles, each deck picks its own.
• Signature element: one memorable, brief-true motif per artifact (NOT a color bar or accent stripe — those read as AI filler).
• Avoid the three AI-default looks: (1) cream #F4F1EA + high-contrast serif
  • terracotta; (2) near-black + single acid-green/vermilion accent; (3) broadsheet hairline rules, zero radius, newspaper columns. Where the brief leaves an axis free, don’t spend that freedom on a default.

Level 3 — Accent: Aesthetic

Pick this when the skill must look intentional.

• Mood system: swiss | editorial | flat | glass | dark drives the regime; one mood per artifact, one radius/stroke language.
• Token system (4 parts): palette as 4–6 named hex; type as 2+ roles (characterful display used with restraint + complementary body + utility face); layout as one-sentence prose + ASCII wireframes; signature as the single unique element.
• Assertion headlines: full sentences with a verb — a conclusion, not a topic.
• Typography floor: body text readable at projection scale (≥17px cards, labels ≥17px, metric values 30–48px); re-check overflow after any font change.
• Restraint: spend your boldness in one place — let the signature be the one memorable thing, keep everything else quiet. Chanel’s rule: before shipping, remove one accessory. Match complexity to the vision; elegance is executing the chosen vision well.
• Structural honesty: numbering/eyebrows/dividers should encode something true about the content, not decorate it (numbered markers only if it’s actually a sequence).

Process — the build loop

Adapted from the official skill-creator flow, with an accent pass added:

1. Capture intent — what should the skill enable? when should it trigger? what’s the output format? do we need test cases (objective outputs do; subjective ones often don’t)?
2. Draft SKILL.md — follow Level 0; choose accents from Levels 1–3 that fit the task.
3. Test prompts — 2–3 realistic user phrasings; save to evals/evals.json.
4. Parallel runs — with-skill vs baseline subagents in the same turn; capture total_tokens / duration_ms to timing.json (only chance to get them).
5. Grade — objective assertions with text / passed / evidence, no partial credit; superficial pass = fail. Subjective quality → human judgment.
6. Accent pass (added) — on each iteration ask: did we keep it technological, creative, and aesthetically disciplined? Did it slip into a default look or a monolith?
7. Improve — generalize from feedback; keep the prompt lean; explain the why; if all test runs wrote the same helper, bundle it into scripts/.
8. Optimize description — generate ~20 trigger queries (mix should/should-not, include near-misses and casual typos), split 60/40 train/test, iterate up to 5× to get best_description by test score.
9. Package — package_skill → .skill file; preserve the original name.

Release checklist

• Level 0 hard rules all satisfied (frontmatter, <500 lines, gates green)?
• Chosen accents actually amplified, not just “it works”?
• Escaped the three AI-default looks (Level 2)?
• Token system coherent: one mood, ≤2 typefaces, ≤4 accent roles, zero raw hex?
• Signature element present and brief-true (not a stripe/bar)?
• Description triggers reliably, including casual/near-miss phrasings?

A skill that passes Level 0 and at least one accent is shippable. A skill that passes all three accents is exceptional.

Boundaries

• Do not use to perform the domain task itself; it designs or upgrades skills.

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