[BUG] High memory consumption when CC is auto-downloading a new version of itself

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

I launched Claude Code in the directory of a small existing project. It almost immediately said it was using a lot of memory, and recommended I do /heapdump.

Here is the JSON diagnostics file:

7dad8859-56ac-4b37-930d-04e0f9dc7212-diagnostics.json

I asked CC to analyze the heap dump. Here is what it said:

== begin ==

⏺ Here's the picture. The key finding is in that URL:

https://storage.googleapis.com/claude-code-dist-.../claude-code-releases/2.1.74/darwin-arm64/claude

Claude Code is downloading a self-update binary — the full claude native binary for darwin-arm64. The 181 MB Response object is holding
that HTTP response, and the body is being buffered into 4,880 x 512 KB ArrayBuffers (totaling ~2.44 GB) plus 124 x 256 KB buffers (~31
MB).

Here's the breakdown:

  ┌─────────────────────────────┬───────────┐
  │            What             │   Size    │
  ├─────────────────────────────┼───────────┤
  │ ArrayBuffers (512KB x 4880) │ ~2,441 MB │
  ├─────────────────────────────┼───────────┤
  │ ArrayBuffers (256KB x 124)  │ ~31 MB    │
  ├─────────────────────────────┼───────────┤
  │ Response object (native)    │ ~182 MB   │
  ├─────────────────────────────┼───────────┤
  │ Total                       │ ~2.7 GB   │
  └─────────────────────────────┴───────────┘

What happened: Within the first 28 seconds of startup, Claude Code v2.1.73 detected that v2.1.74 was available and began fetching the
update binary. The response body stream is being consumed but the data is accumulating in memory — the ReadableStream body is being
buffered rather than streamed to disk. At the observed growth rate of ~70 GB/hour (~20 MB/s), it was filling up memory fast enough to
trigger the high-memory warning.

In short: This is a bug in Claude Code's auto-update mechanism. The update download is buffering the entire binary into heap memory (as
thousands of 512KB ArrayBuffers) instead of streaming it directly to disk. For a large native binary, this blows up memory usage almost
immediately. This is a Claude Code bug, not something in your project.

== end ==

It also summarized: "The key finding: the update download URL (claude-code-releases/2.1.74/darwin-arm64/claude) buffering into ~4,880 x 512KB ArrayBuffers"

What Should Happen?

Should not use excess memory when self-updating

Error Messages/Logs

Steps to Reproduce

Not reproducible

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.73

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_