Create Skill

Create Skill

Purpose / When to Activate

Activate when:

• A new capability is needed that no existing skill covers
• A skill is being extracted from agent logic that has become reusable
• Extending a forked GAAI installation with project-specific skills

This skill is self-referential: it uses the agentskills.io spec to author a spec-compliant skill.

Prerequisites

Before activating:

1. Confirm no existing skill already covers the intended capability (check README.skills.md)
2. Confirm the new skill is a pure execution unit — it executes, it does not reason
3. Confirm the skill belongs to exactly one category (discovery / delivery / cross)
4. Have a clear, one-sentence description of: WHAT it does and WHEN to activate it

If a skill "appears to think" in the design, it is wrongly scoped. Redesign or split.

Process

Step 1 — Name and classify

Derive the skill name from the action it performs:

• Use lowercase kebab-case
• Name should be a verb phrase: generate-stories, qa-review, memory-compact
• Category: discovery (produces artefacts) | delivery (implements/validates) | cross (shared utility)

Verify name does not conflict with an existing skill in README.skills.md.

Step 2 — Define inputs and outputs explicitly

List every input the skill requires. Be specific:

• What file paths does it read?
• What structured data does it receive from the invoking agent?
• What context is assumed to be present?

List every output the skill produces:

• File paths created or modified
• Structured data returned to the agent
• Side effects (backlog state changes, memory updates)

If inputs or outputs are unclear, the skill is not ready to be written. Clarify first.

Step 3 — Write the SKILL.md frontmatter

---
name: {skill-name}                  # matches directory name exactly
description: {one sentence}         # WHAT it does + WHEN to activate
license: ELv2
compatibility: Works with any filesystem-based AI coding agent
metadata:
  author: {author}
  version: "1.0"
  category: {discovery|delivery|cross}
  track: {discovery|delivery|cross-cutting}
  id: SKILL-{CAT}-{NNN}
  updated_at: {YYYY-MM-DD}
  status: stable|experimental       # use experimental for new/unproven skills
inputs:
  - {input_1}: {description}
  - {input_2}: {description}
outputs:
  - {output_path_or_description}
---

Description rule: Must be one sentence, ≤ 1024 characters. Format:

"{Verb phrase that describes the output} when {activation condition}."

Example: "Generate Stories from an Epic with testable acceptance criteria when Discovery is refining a new feature scope."

Step 4 — Write the skill body

Required sections:

# {Skill Title}

## Purpose / When to Activate
When and why an agent should invoke this skill. Be explicit.

## Process
Numbered steps. Each step produces a specific output or advances the state.
Steps must be deterministic: same inputs → same outputs.

## Quality Checks
What must be true for the output to be acceptable.
List as assertions, not descriptions.

## Outputs
Exact file paths or structured outputs produced.

## Non-Goals
What this skill must NOT do. Prevents scope creep.

Add a final line if applicable:

No silent assumptions. Every {X} becomes explicit and governed.

Step 5 — Create directory and file

.gaai/core/skills/{category}/{skill-name}/SKILL.md

SKILL.md filename is always uppercase (spec requirement).

Optional subdirectories (create only if needed):

• references/ — supporting documents the skill references
• assets/ — templates or static files the skill produces

Step 6 — Update ALL relevant indices (MANDATORY)

This step is non-negotiable. A skill that is not indexed is invisible to agents.

6a. Skills index YAML:

• Invoke build-skills-index to regenerate both .gaai/core/skills/skills-index.yaml (core) and .gaai/project/skills/skills-index.yaml (project)
• Verify the new skill appears in the generated index with correct id, name, path, and tags

6b. Skills README:

• Core skills: update .gaai/core/skills/README.skills.md — add the skill to the appropriate category section
• Project skills: update .gaai/project/skills/README.md — add the skill to the appropriate section

6c. Domain index (if domain-scoped skill):

• If the skill belongs to a domain (e.g., domains/content-production/), update the domain's index.md in memory:
  • .gaai/project/contexts/memory/domains/{domain}/index.md — add a row to the skills table
• This ensures domain sub-agents discover the skill when loading their domain context

Failure to update any of these indices means the skill is effectively invisible — agents cannot discover it, and it will not be loaded during delivery or discovery sessions.

Step 7 — Reference in agent file

If the skill is intended for a specific agent (Discovery) or a delivery sub-agent, add it to the agent's skill list in:

• .gaai/core/agents/discovery.agent.md — Skills Used section
• Or the relevant sub-agent file in .gaai/core/agents/sub-agents/ (planning, impl, qa)
• Or neither, if it's a general cross skill invoked opportunistically

Quality Checks

• Skill name matches directory name exactly
• SKILL.md frontmatter has name and description at top level (spec requirement)
• Description is ≤ 1024 characters, one sentence
• All inputs are explicitly declared
• All outputs are explicitly declared with file paths where applicable
• Skill body has all 5 required sections
• Non-Goals section explicitly prevents scope creep
• README.skills.md updated
• health-check.sh passes after creation

Non-Goals

This skill must NOT:

• Design agent behavior or orchestration logic (that is an agent concern)
• Make decisions about when to activate the skill (the invoking agent decides)
• Merge or replace an existing skill (deprecation requires explicit human decision)

A skill that appears to think is wrongly designed. Redesign before authoring.