How to give Claude or ChatGPT your entire codebase (the right way)

A developer created ctxpack, a zero-dependency CLI tool that packages an entire codebase into a single file for AI models like Claude and GPT. The tool handles three common problems: it orders files into a single document with a file index, automatically masks secrets like API keys, and estimates token counts to fit within model context windows. ctxpack is MIT-licensed and available on GitHub.

At some point every "let me just paste my code into the AI" session hits a wall. You want the model to reason about the whole project — not one file — so you start copy-pasting directories. Three things go wrong, usually in this order: Here's a workflow that handles all three, whether you build the tooling yourself or use an off-the-shelf one. Models reason better over a single, well-ordered document than over 30 pasted snippets. Walk the repo, skip the noise node modules , build output, images, lockfiles , and emit each file with a clear header. A file index at the top helps the model build a mental map before it reads any code. This is the step people skip. Anything credential-shaped — sk-... , ghp ... , AKIA... , sk live ... , -----BEGIN PRIVATE KEY----- — should be masked automatically, not by remembering to check. A prompt log is a place secrets go to leak; treat the bundle like a public paste. Estimate the bundle's token count and compare it to your target model Claude ~200K, GPT-5 ~400K, Gemini 2.5 Pro ~1M . If you're over, don't truncate blindly — drop the largest file bodies but keep every file listed , so the model still knows the project's full shape. ctxpack https://github.com/trongtruong110-ux/ctxpack is a zero-dependency CLI that does all three: whole repo, budgeted for Claude, secrets masked, written to a file npx github:trongtruong110-ux/ctxpack . --model claude-fable-5 -o context.md too big? fit it to a budget keeps the file map, trims largest bodies npx github:trongtruong110-ux/ctxpack . --fit 150000 -o context.md ctxpack: 214 files packed tokens: ~147,900 74% of Claude 200,000 ctx redacted: 3 secret s Then paste context.md or attach it and ask your question against the full project. ctxpack is MIT-licensed and free: https://github.com/trongtruong110-ux/ctxpack https://github.com/trongtruong110-ux/ctxpack . If you've got a workflow for feeding whole projects to an LLM, I'd like to hear it.