grillmester-create-a-skill

name	grillmester-create-a-skill
description	Create, revise, review, or diagnose a portable Agent Skill for OpenCode v1, including native discovery, permissions, and an optional slash-command adapter. Use when a user asks to create or improve a skill, investigate why one does not load, or validate skill behavior.

Create an OpenCode-compatible Agent Skill

Create, revise, or diagnose one portable Agent Skill. Repository instructions, the installed OpenCode v1 contract, and the target repository's chosen skill root govern the artifact.

Choose the mode

• Create or revise — inspect, design, edit, reconnect callers, and validate.
• Diagnose or review — inspect and validate read-only, then report evidence and recommendations. Edit only if the user also requested implementation.

Stop and recommend extending an existing owner when the requested behavior is already owned by a skill or reference.

1. Inspect the target

Inspect applicable AGENTS.md, OpenCode config, existing skills, neighboring commands, and repository validation. Determine which supported root the repository already uses:

• .agents/skills/<name>/SKILL.md for a portable project skill;
• .opencode/skills/<name>/SKILL.md for an OpenCode-specific project skill;
• the corresponding supported user-level root only when the user requested a personal skill.

Do not introduce a parallel skill tree without a material reason and user agreement. State the skill's one job, its boundary, current callers, and whether it needs a separate slash command.

2. Design discovery and invocation

Use portable skill frontmatter:

• name — required, kebab-case, and equal to the directory name;
• description — required, concise, and specific enough for model discovery;
• license, compatibility, and metadata — optional only when they convey a real portable contract.

Do not copy client-specific invocation keys into an OpenCode skill. OpenCode loads skills through the skill tool. Control model access with ordered permission.skill patterns in agent or project configuration. When a direct slash entry point matters, add a native command with the same stable ID under the selected OpenCode commands/ root; the wrapper must load the skill and pass $ARGUMENTS as user input.

For access rules, put "*" before narrower patterns because the last matching rule wins. Use ask for a source skill that was intended to require deliberate human invocation; this is an approval approximation, not provenance-aware manual-only behavior.

3. Design the information hierarchy

Apply the authoring principles. Keep instructions needed every time in SKILL.md; put conditional reference, scripts, and assets beside it and link them with an explicit loading condition. Consult only the needed heading in the glossary.

4. Implement and reconnect

Write the smallest complete skill and only justified bundled resources. Update direct callers, command wrappers, adapter policy, and provenance affected by a name or invocation change. If a repository generates its OpenCode target, change the canonical source or target overlay and regenerate; never hand-edit the generated output.

Complete the edit when names are stable, links resolve, target roots do not compete, permissions preserve the intended boundary, and the diff contains no unrelated client assumptions.

5. Validate and forward-test

Immediately before validation, read the OpenCode validation checklist. Run its safe structural and runtime checks using a disposable target/config copy when the client may create dependency artifacts. Test explicit command invocation, positive skill discovery, a close negative prompt, and every distinct branch that can be exercised without unauthorized external writes.

In diagnose mode, a failing target is valid evidence. In create/revise mode, iterate until structure, discovery, permission behavior, and the final diff match the intended contract.