[BUG] Compact failed meaning that there was no way to continue the current session

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?

The session reached ~90% of the context window. There was no warning. I got this message:

⎿  Error editing file
⎿  API Error: The model has reached its context window limit.
⎿  Context limit reached · /compact or /clear to continue

I attempted to compact:

❯ /compact
⎿ Error: Error during compaction: Error: Conversation too long. Press esc twice to go up a few messages and try again.

This is a chicken and egg issue. If /compact is the way to recover from this state but /compact cannot run because of that state, the user has no way to continue without losing their context. It is essential that /compact works in this scenario.

What Should Happen?

/compact should always work. There needs to be something akin to a reserve tank so it can always work.

Error Messages/Logs

⎿  Error editing file
    ⎿  API Error: The model has reached its context window limit.
    ⎿  Context limit reached · /compact or /clear to continue

  ❯ /compact
    ⎿  Error: Error during compaction: Error: Conversation too long. Press esc twice to go up a few messages and try again.

Steps to Reproduce

1. During a session I got:

⎿  Error editing file
⎿  API Error: The model has reached its context window limit.
⎿  Context limit reached · /compact or /clear to continue

1. I attempted to compact:

❯ /compact
⎿ Error: Error during compaction: Error: Conversation too long. Press esc twice to go up a few messages and try again.

Claude Model

Opus

Is this a regression?

Yes, this worked in a previous version

Last Working Version

2.1.62

Claude Code Version

2.1.63 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

PowerShell

Additional Information

_No response_