skill-preflight

Creation Guard: Pre-Flight Duplicate Check

Prevent duplicate functionality by analysing existing skills, agents, and rules before creating new ones. Intercepts creation intent, searches for overlap, and recommends one of 5 actions.

When to Use

Invoke before creating ANY new:

• Skill (skills/*/SKILL.md)
• Agent (.claude/agents/*.md)
• Rule (rules/*.md)

Trigger phrases:

• "Create a skill for..."
• "I want a new skill that..."
• "Let's add an agent for..."
• "We need a rule for..." / "add a rule that..."
• Any intent to create new automation/tooling

Rules need this most, not least. A duplicate skill is visible — it shows up in the catalogue and the slash menu. A duplicate rule is invisible: both copies load silently as system instructions, and the first sign of trouble is two subtly different versions of the same policy competing. Rules are also break-the-glass infrastructure, so an unnecessary one is a standing cost on every session. Check for an existing rule to amend before writing a new one — amendment is the usual correct outcome for rules, where PROCEED is the usual outcome for skills.

Process

Step 1: Identify the Proposal

Extract from the request:

• Name: Proposed name (kebab-case)
• Type: skill | agent | rule
• Purpose: What it does (one sentence)
• Key Functions: 3-5 main capabilities
• Keywords: Searchable terms related to functionality

Step 2: Search Existing Artifacts

Run these searches in parallel:

1. Read skills/shared/skill-index.md — scan the categorised table for potential duplicates by name and purpose
2. Keyword search — grep skills, agents, and rules for each keyword:

Grep for each keyword across:
  - skills/*/SKILL.md (frontmatter + body)
  - .claude/agents/*.md (frontmatter + body)
  - rules/*.md (frontmatter + body)

1. Agent scan — read frontmatter of each agent to check purpose overlap:

Glob: .claude/agents/*.md
Read first 20 lines of each match