Cross-platform session handoff (Codex ↔ Claude)

[laynepenney]

Problem

When an agent switches tools (Codex rate-limited, swap to Claude), all session context is lost. The new tool starts fresh with no knowledge of what the previous tool was working on, which files were open, or what the conversation state was.

Desired behavior

When Atlas switches from Codex to Claude (or vice versa):

• Recent session transcript is available to the new tool
• Current working files and their state are carried over
• Active tasks/claims are preserved
• The agent's identity (agent_id, display_name) stays the same

Possible approaches

1. Journal as handoff: write a structured journal entry at session end that the new tool reads on startup. Already partially exists via recall_journal.
2. Session export/import: serialize the current session state to a file that the new tool ingests.
3. Recall as the bridge: both tools read from the same recall index. The new tool searches for recent activity by this agent_id.

Context

Atlas frequently switches between Codex (o3) and Claude (sonnet) depending on rate limits and task type. The handoff is currently manual and lossy.