I did some debugging on this today. The results are... sobering.
Memory comparison of AI coding CLIs (single session, idle):
| Tool | Footprint | Peak | Language |
|-------------|-----------|--------|---------------|
| Codex | 15 MB | 15 MB | Rust |
| OpenCode | 130 MB | 130 MB | Go |
| Claude Code | 360 MB | 746 MB | Node.js/React |
That's a 24x to 50x difference for tools that do the same thing: send text to an API.
vmmap shows Claude Code reserves 32.8 GB virtual memory just for the V8 heap, has 45% malloc fragmentation, and a peak footprint of 746 MB that never gets released, classic leak pattern.
On my 16 GB Mac, a "normal" workload (2 Claude sessions + browser + terminal) pushes me into 9.5 GB swap within hours. My laptop genuinely runs slower with Claude Code than when I'm running local LLMs.
I get that shipping fast matters, but building a CLI with React and a full Node.js runtime is an architectural choice with consequences. Codex proves this can be done in 15 MB. Every Claude Code session costs me 360+ MB, and with MCP servers spawning per session, it multiplies fast.
Memory comparison of AI coding CLIs (single session, idle):
That's a 24x to 50x difference for tools that do the same thing: send text to an API.vmmap shows Claude Code reserves 32.8 GB virtual memory just for the V8 heap, has 45% malloc fragmentation, and a peak footprint of 746 MB that never gets released, classic leak pattern.
On my 16 GB Mac, a "normal" workload (2 Claude sessions + browser + terminal) pushes me into 9.5 GB swap within hours. My laptop genuinely runs slower with Claude Code than when I'm running local LLMs.
I get that shipping fast matters, but building a CLI with React and a full Node.js runtime is an architectural choice with consequences. Codex proves this can be done in 15 MB. Every Claude Code session costs me 360+ MB, and with MCP servers spawning per session, it multiplies fast.