inspect-claude-binary

name	inspect-claude-binary
description	Determine what type of Claude Code binary you have (JS bundle vs Bun ELF), its version, and what patchable strings are present.

Inspect Claude Code Binary

Determine Binary Type

# Find the real binary path
CLAUDE_BIN=$(readlink -f "$(which claude)")

# Check file type
file "$CLAUDE_BIN"

• JS bundle: Node.js script executable, ASCII text — has #!/usr/bin/env node shebang
• Bun ELF binary: ELF 64-bit LSB executable, x86-64 — compiled native binary (~245MB)

Version Transition Point

Versions	Format	Size
v2.1.94 - v2.1.112	JS bundle (cli.js)	~13MB
v2.1.113+	Bun ELF binary (bin/claude.exe)	~245MB

v2.1.112 is the last JS-based version. v2.1.113 is the first Bun binary (Bun v1.3.13).

Quick Checks

# File size (JS ~13MB, binary ~245MB)
wc -c "$CLAUDE_BIN"

# First bytes — JS has shebang, ELF has magic header
head -c 20 "$CLAUDE_BIN"

Locate Patchable Strings (Binary Only)

# Key export mappings — reveals minified function names
strings "$CLAUDE_BIN" | grep 'isChannelAllowlisted:()=>'
strings "$CLAUDE_BIN" | grep 'DevChannelsDialog:()=>'

# Other useful markers
strings "$CLAUDE_BIN" | grep -c 'bun'          # ~1480 hits confirms Bun runtime
strings "$CLAUDE_BIN" | grep 'I am using this for local development'

The export mappings follow the pattern EXPORTNAME:()=>FUNCNAME — use the FUNCNAME to find the actual function body in the embedded JS source.

Reference

Full investigation evidence in docs/research/patcher-investigation/.