#26441 feat(build): add --metafile-md CLI option for LLM-friendly bundle analysis

Summary

• Adds --metafile-md CLI option to bun build that generates a markdown visualization of the module graph
• Designed to help Claude and other LLMs analyze bundle composition, identify bloat, and understand dependency chains
• Reuses existing metafile JSON generation code as a post-processing step

Features

The generated markdown includes:

1. Quick Summary - Module counts, sizes, ESM/CJS breakdown, output/input ratio
2. Largest Input Files - Sorted by size to identify potential bloat
3. Entry Point Analysis - Shows bundle size, exports, CSS bundles, and bundled modules
4. Dependency Chains - Most commonly imported modules and reverse dependencies
5. Full Module Graph - Complete import/export info for each module
6. Raw Data for Searching - Grep-friendly markers in code blocks:
   • [MODULE:], [SIZE:], [IMPORT:], [IMPORTED_BY:]
   • [ENTRY:], [EXTERNAL:], [NODE_MODULES:]

Usage

# Default filename (meta.md)
bun build entry.js --metafile-md --outdir=dist

# Custom filename
bun build entry.js --metafile-md=analysis.md --outdir=dist

# Both JSON and markdown
bun build entry.js --metafile=meta.json --metafile-md=meta.md --outdir=dist

Example Output

See sample output: https://gist.github.com/example (will add)

Test plan

• Test default filename (meta.md)
• Test custom filename
• Test both --metafile and --metafile-md together
• Test summary metrics
• Test module format info (ESM/CJS)
• Test external imports
• Test exports list
• Test bundled modules table
• Test CSS bundle reference
• Test import kinds (static, dynamic, require)
• Test commonly imported modules
• Test largest files sorting (bloat analysis)
• Test output/input ratio
• Test grep-friendly raw data section
• Test entry point markers
• Test external import markers
• Test node_modules markers

All 17 new tests pass.

🤖 Generated with Claude Code