Agent Skill Design

Agent Skill Design

Use this skill to design agent skills as progressive behavioral interfaces. The goal is to turn repeated judgment, workflow, taste, or tool use into a skill that loads at the right time and changes agent behavior at the moment it matters.

Core thesis:

A skill is a progressive behavioral interface for agents: metadata controls invocation, the body carries judgment, references manage context depth, scripts provide deterministic substrate, and outputs preserve continuation context.

Design Axioms

• Invocation contract: name and description decide whether the skill is read at all. Put trigger conditions in metadata where they can influence loading.

• Behavioral kernel: the body should teach the agent what to judge, what to preserve, what to tighten, and how to act differently. Topic explanation usually belongs in reference material.

• Boundary design: add fixed contracts where reliability matters. Preserve flexible judgment where the work is interpretive, immature, or taste-dependent.

• Context economy: SKILL.md should contain what every invocation needs. references/ should hold optional depth. scripts/ should handle deterministic or fragile work. assets/ should contain output materials.

• Continuation surface: agent-facing scripts and CLIs should report the result and preserve enough state, ambiguity, paths, and next actions for the next agent step.

• Principle-first iteration: fold new feedback into cleaner concepts, sharper vocabulary, better medium split, or a stronger structure before adding local prohibitions.

• Fit boundary: real cases are evidence. Let a case generalize the skill, narrow the skill, move into references, or remain local according to the fit boundary it reveals.

Skill Shape Lenses

A skill's shape should emerge from the behavior it is meant to improve: the judgment it carries, the boundary it sets, the context it loads, and the deterministic work it delegates.

Use these lenses while designing or revising:

• Behavior center: What agent behavior should become more stable, sharper, or more aligned with the user's taste?
• Boundary hardness: Which parts need a fixed contract, and which parts should preserve semantic freedom?
• Fit boundary: Should the case evidence generalize the skill, narrow its scope, become an example, or remain local?
• Context timing: Which information should be visible in metadata, loaded in SKILL.md, or deferred to references?
• Deterministic substrate: Which repeated, fragile, or side-effecting work belongs in scripts or CLIs?
• Continuation surface: Which outputs need to guide the next agent step?
• Validation surface: What realistic prompt would show that the skill changed behavior?

Diagnostic Vocabulary

Use diagnostic terms to explain concrete structural issues:

• Invocation burial: trigger conditions live in the body instead of description.
• Description shortcut: metadata summarizes the workflow so strongly that an agent may act from metadata alone instead of reading the body.
• Topic wrapper: the skill names a domain but not the situations that should trigger it.
• Behavior gap: the skill contains useful information but does not change what the agent will do.
• Workflow cosplay: a judgment or taste skill is forced into generic steps.
• Context sediment: SKILL.md accumulates optional examples, background, or long explanation that should be in references.
• Patch sediment: iteration adds local prohibitions, exceptions, and "don't do X" clauses instead of absorbing feedback into clearer principles or structure.
• Case overfit: a general skill absorbs local names, examples, exceptions, or scenario details as if they were durable principles.
• Determinism overreach: flexible semantic work is prematurely forced into a schema, enum, script, or rigid process.
• Softness leak: a flexible boundary is preserved, but no lenses or constraints help the agent handle it responsibly.
• Execution prose: fragile repeatable work is described in text instead of captured in a script or CLI.
• Dead output: a helper produces a result but gives no completeness signal, ambiguity note, artifact path, or next action.

Medium Split

Use this default medium split:

• name: short searchable action or judgment, matching the directory.
• description: concrete invocation contract; include all durable trigger conditions here.
• SKILL.md: core theory, decision lenses, failure vocabulary, resource map, output shape.
• references/: optional theory, long examples, source docs, detailed rubrics, provider-specific notes.
• scripts/: deterministic heavy work, fragile file operations, validation, linking, generation.
• assets/: templates or media used in outputs, not explanatory material.

Rewrite Moves

When improving a skill, prefer structural moves over wording polish:

• Move trigger language from body to description.
• Replace topic summaries with a behavioral kernel.
• Let the skill's shape follow the behavior, boundary, context timing, and deterministic substrate it needs.
• Classify case feedback as general principle, scope narrowing, reference example, validation prompt, or local context.
• Turn generic steps into lenses, contracts, or deterministic scripts.
• Move optional depth into references/ and state when to read it.
• Add a script when correctness depends on repeated file, CLI, parsing, or validation work.
• Make helper output agent-friendly: result, completeness, ambiguity, artifact paths, and next action.
• Split a skill when two trigger surfaces need different behavior.
• Remove content that a capable model already knows.
• Convert patch sediment into a stronger positive principle, diagnostic term, or structural rewrite.

For bloated skills, identify which material belongs in a different medium.

Naming Taste

Name the skill after the durable behavior, judgment, or design surface it improves.

Prefer names that expose one of these:

• Action: what the agent is doing repeatedly.
• Judgment: what decision the skill makes sharper.
• Artifact: what object the skill shapes.
• Failure mode: what recurring drift the skill corrects.
• Medium: what tool or interface the skill operates through, when that is the real trigger.

A good name should help the metadata trigger correctly before the body is loaded.

Output When Helping

When helping design or diagnose a skill, keep the response compact:

Agent Skill Design Notes
- Invocation contract:
- Behavioral kernel:
- Shape lenses:
- Fit boundary:
- Medium split:
- Soft boundary:
- Main smell:
- Rename or split:
- Validation prompt:

Use the full shape only when useful. For small edits, a direct rewrite plus one or two notes is better.

References

Load references/personal-theory.md when doing a broad redesign, choosing between competing skill names, explaining the theory behind a recommendation, or turning a user's raw taste and experience into a reusable skill design system.

How to Improve This Skill

If real use reveals a possible improvement, keep the task moving and use report-biaoo-skill-feedback. If unavailable, retain a privacy-safe Biaoo/skills issue draft rather than submitting from this session.