ai-codex: Pre-index your codebase to save Claude tokens

What ai-codex does

ai-codex is a single script that scans your project and generates five compact markdown files to pre-index your codebase for Claude Code conversations. This eliminates the initial exploration phase where Claude typically spends 10-20 tool calls reading files, scanning directories, and checking functions.

How it works

You run npx ai-codex once to generate these files:

• routes.md — every API route with methods and auth tags
• pages.md — full page tree with client/server flags
• lib.md — all library exports with function signatures
• schema.md — database schema compressed to key fields only
• components.md — component index with props

Then add one line to your CLAUDE.md telling Claude to read these files first. Every future conversation skips the exploration phase entirely.

Performance impact

On large projects, the exploration phase typically burns 30-50K tokens before any real work begins. The creator's example project had 950+ API routes and 255 DB models:

• Without codex: ~15 Serena/Read calls to understand the finance module
• With codex: 5 grep calls on the pre-built index, instant full picture — routes, pages, schema, lib exports, components
• All in parallel, all under 2 seconds

Technical details

The tool works with Next.js (App Router & Pages Router) and generic TypeScript projects. It auto-detects Prisma schemas. The entire tool was designed and built by Claude Code itself in a single conversation session. It's MIT licensed and available on GitHub.