Skill Bill: A Markdown-Based Governance Framework for AI Coding Skills

What Skill Bill Is

Skill Bill is a governance framework for AI coding skills built entirely in Markdown. It addresses common problems developers face when managing multiple AI prompts across different agents: naming drift, duplicated logic, platform-specific code creeping into generic skills, and lack of a single source of truth.

How It Started

The developer began with individual skills for specific tasks: a code review prompt for Android/KMP work, a gradle check skill with conventions for fixing issues instead of suppressing them, a feature flag skill, and a skill for implementing features from design docs. After accumulating about a dozen skills scattered across agents, they experienced the "familiar rot" of inconsistent naming and Kotlin-specific logic appearing in supposedly generic skills.

The Orchestrator Breakthrough

The key innovation was creating feature-implement, a skill that calls other skills in sequence. This orchestrator takes a design doc, creates a plan, asks about feature flag strategy, implements code, runs reviews, and checks completeness. A single feature-implement run chains 10-12 skill invocations: an orchestrator, a stack-detecting code review router, 3-5 specialist reviewers running in parallel, a quality check, PR description, and optional feature flag setup.

Cost Considerations

The developer uses Claude Code with Max subscription and didn't initially consider usage costs. However, a friend using Codex Pro subscription reported that a single code-review skill invocation (not the full chain) burns through 40-50% of the 5-hour Pro rate limit. Copilot uses a different billing model (per conversation turn rather than per token volume), making it more cost-effective for this approach.

Technical Architecture

The framework evolved to support multiple programming languages through structured Markdown that functions like code:

• Inheritance: Base skills with platform overrides
• Routing logic: Stack detection and delegation to appropriate specialists
• Interface contracts: Defined relationships between skills
• Validation: Enforces naming rules and structure to prevent repository rot

Once the base layer became properly generic, adding PHP support was straightforward, followed by Go. The framework now includes 44 skills across Kotlin, Android/KMP, Kotlin backend, PHP, and Go.

Key Features

• Base skills that route automatically to the right platform specialist
• A validator that enforces naming rules and structure
• Single repository that syncs to Claude Code, Copilot, GLM, and Codex
• Orchestrator skills like feature-implement that chain everything together end-to-end
• Currently strongest for Kotlin-family and Go/PHP backends, but designed to extend to new platforms

Practical Implications

The developer discovered that prompt repositories have the same engineering problems as regular software. By treating skills like code—with contracts, validation, and composability—the entire system became dramatically more maintainable. The framework is available on GitHub under MIT license at https://github.com/Sermilion/skill-bill.