[BUG] mcp__claude-in-chrome__computer stores temp file path in base64 image data field instead of actual image data

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?

Bug Report

Tool: mcp__claude-in-chrome__computer (screenshot tool)

### What happens

When the computer tool captures a screenshot, the session .jsonl file records the result with a temp file path (e.g.
/var/folders/.../T/steer/c9060e38png) in the source.data field instead of actual base64-encoded image data.

### Effect

When Claude Code resumes that session in a later run, the Anthropic API immediately rejects the request with:

400 {"type":"error","error":{"type":"invalid_request_error","message":"Could not process image"}}

The session is permanently broken because:

1. The source.type is base64 but the data field contains a file path string
2. The temp file is deleted between runs, so the data can't be recovered

### Workaround

Manually edit the .jsonl session file and replace the bad image entry:

```json
{"type": "image", "source": {"type": "base64", "media_type": "image/png", "data": "/var/folders/..."}}

with a text placeholder:

{"type": "text", "text": "[screenshot unavailable — temp file was deleted]"}

Environment

• Claude Code version: 2.1.77
• Platform: macOS (darwin arm64)
• MCP server: claude-in-chrome (in-process)

What Should Happen?

The computer tool should embed the actual base64-encoded PNG data in the data field, not a path to a temp file.

Error Messages/Logs

400 {"type":"error","error":{"type":"invalid_request_error","message":"Could not process image"}}

Steps to Reproduce

capture a screenshot, end session, try to continue session

Claude Model

Sonnet (default)

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.77 (Claude Code)

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

iTerm2

Additional Information

_No response_