interskill

interskill

Skill authoring toolkit for Claude Code plugins.

What this does

interskill guides you through creating Claude Code skills that actually trigger reliably and do what they promise. It combines two phases: spec-driven creation (structure, frontmatter, invocation control, description engineering for Claude Search Optimization) and TDD-adapted pressure testing (invoke the skill in edge cases, verify it handles them).

The audit skill checks existing skills against the Claude Code spec — structure, frontmatter validity, CSO compliance, and whether the skill's description is actually triggering it in the right contexts.

Installation

First, add the interagency marketplace (one-time setup):

/plugin marketplace add mistakeknot/interagency-marketplace

Then install the plugin:

/plugin install interskill

Usage

Create a new skill:

/interskill:skill

Or ask naturally:

"create a skill for database migration safety"
"write a new skill that handles deployment"

Audit an existing skill:

/interskill:audit

Or:

"check if my skill description triggers correctly"
"audit the flux-drive skill"

Architecture

skills/
  create/
    SKILL.md                  Unified creation workflow (spec + TDD phases)
    references/               17 reference docs (best practices, CSO, patterns, etc.)
    templates/                Starter templates (simple, router)
    workflows/                Sub-workflows (add reference, add script, upgrade to router, etc.)
  audit/
    SKILL.md                  Skill verification workflow

The create skill ships with a full knowledge cluster: 17 reference documents covering Anthropic's official skill spec, persuasion principles, CSO optimization, common patterns, and testing strategies. The audit skill verifies structure, frontmatter, and invocation control against these references.

Ecosystem

interskill was extracted from interdev, which consolidated two earlier skills (create-agent-skills and writing-skills) into the unified create + audit pair. See also interplug for plugin-level development tooling.