Repo Tokens: GitHub Action Adds Token Count Badge for LLM Context Window Awareness

Repo Tokens is a GitHub Action that calculates the token count of your codebase and adds a visual badge to your README indicating how much of a large language model's context window your repository occupies. The goal is to make token size a visible metric, similar to bundle size badges for JavaScript libraries, encouraging leaner codebases that are more compatible with AI coding agents.

How It Works

The action uses tiktoken for tokenization. It runs approximately 60 lines of inline Python and takes about 10 seconds to execute. It's implemented as a composite action.

Configuration and Output

The context window size is configurable, defaulting to 200,000 tokens (matching the size of Claude models). The badge color reflects the percentage of the configured context window your codebase fills:

• Green: Under 30%
• Yellow: 50-70%
• Red: 70%+

The action updates the README file but does not automatically commit the changes, allowing your workflow to control the git strategy.

This type of tool is useful for developers working with AI assistants, as keeping a codebase within an LLM's context window allows the agent to maintain full awareness of the project structure and dependencies during coding tasks.