[BUG] 2.1.296: --input-format=stream-json requires --print error on VS Code extension (session resume fails)

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?

Description

After updating the VS Code extension to 2.1.296, resuming an existing session (or starting a new one from the extension) fails immediately with:

Error: --input-format=stream-json requires --print.

The process exits right away, but the VS Code chat panel does not surface this error — it just shows an indefinite loading spinner ("inferring"), making it look like a hang rather than a crash.

Environment

• Extension version: anthropic.claude-code 2.1.296
• Platform: Windows 11 + WSL2 (Ubuntu), VS Code Remote-WSL
• Native binary path: ~/.vscode-server/extensions/anthropic.claude-code-2.1.296-linux-x64/resources/native-binary/claude

What I found

Running the exact command the extension spawns, directly in a terminal, surfaces the real error:

~/.vscode-server/extensions/anthropic.claude-code-2.1.296-linux-x64/resources/native-binary/claude \
  --output-format stream-json --verbose --input-format stream-json \
  --max-thinking-tokens=31999 --permission-prompt-tool=stdio \
  --resume=<session-id> \
  --setting-sources=user,project,local --permission-mode=acceptEdits \
  --debug --debug-to-stderr --enable-auth-status --no-chrome --replay-user-messages

Error: --input-format=stream-json requires --print.

Looking at extension.js, the ProcessTransport.initialize() method builds the spawn args:

let r=["--output-format","stream-json","--verbose","--input-format","stream-json"];

--print is never pushed into this args array anywhere in that function, so the native binary's own validation (which apparently now requires --print when --input-format=stream-json is set) rejects it immediately.

What Should Happen?

Either:

the extension should pass --print when required, or
the chat panel should surface the process exit error instead of showing an indefinite spinner

Error Messages/Logs

Error: --input-format=stream-json requires --print.

Steps to Reproduce

1. Use the VS Code extension with an existing session (--resume=<session-id>)
2. Send a message in the chat panel
3. The panel shows "inferring" indefinitely with no output

Claude Model

None

Is this a regression?

Yes, this worked in a previous version

Last Working Version

_No response_

Claude Code Version

2.1.283

Platform

Anthropic API

Operating System

Ubuntu/Debian Linux

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_