Forked session inherits full uncompressed context after parent compaction, causing "exceeds model context limit" #26707

Description

When a long-running session is compacted and then forked, the forked session receives the full uncompressed context (pre-compaction history) rather than the compacted continuation summary. This causes the forked session to immediately hit "Conversation history too large to compact - exceeds model context limit."

Plugins

No response

OpenCode version

1.14.27

Steps to reproduce

1. Start a long session with significant tool use and code changes (enough to trigger compaction)
2. Let the session auto-compact (or trigger /compact manually)
3. Verify the parent session is working normally with compacted context
4. Fork the compacted session via TUI (Ctrl+S or session list → fork)
5. Open the forked session → immediately see:
   Conversation history too large to compact - exceeds model context limit

Screenshot and/or share link

Session too large to compact - context exceeds model limit even after stripping media

Operating System

debian 13

Terminal

No response