Context Compaction (F2)

Rolling summarization of old conversation turns to stay within context limits.

How It Works

1. After each run, check conversation length against the session cap
2. If near cap, compact_history() sends the oldest N messages to the LLM as a one-shot summarization chat
3. The summary replaces those messages, embedded as a [CONTEXT SUMMARY] marker
4. Recent messages stay intact — only the tail is compressed

Session Format v2

Compaction summaries persist across restarts via the session file format v2:

{
  "version": 2,
  "summary": "User asked about X; we decided Y...",
  "messages": [...]
}

Format v1 (bare message array) is still readable — backward compatible.

Config

[gateway]
context_compaction = true