Session Compaction and Restore

Preserving useful working state across compaction, context loss, restart, or seat refresh. Includes Claude compaction restore, Codex resume/fork mechanics, transcript-based mental-model rebuilds, and durable handoff packets.

Long-lived seats are valuable only if they can survive context pressure. If compaction turns a senior seat into a cold-started agent, users will avoid persistent topologies and fall back to throwaway agents.

Use this when

• A seat is approaching compaction or just compacted
• Designing a high-fidelity restore packet for an active workflow
• Distinguishing native runtime resume vs fork vs artifact-backed mental-model rebuild
• Reasoning about what should be preserved vs reconstructable
• Auditing a restore for product-intent preservation (not just detail preservation)

Don't use this when

• The session is fresh and has no working state to preserve
• The intent is to create a new seat from a primed source, that's session-source-fork or agent-starters
• The packet is a one-off snapshot for human review, restore packets are for re-entering active work

The 5 distinctions (do not collapse)

Per the cross-runtime restore/reentry packet standard:

Mode	What it means	Outcome literal
Native resume	Continue the same managed seat with native runtime token	resumed
Fork	New managed seat from prior native runtime conversation; new post-fork token	forked
Rebuild	Fresh-launch seeded with operator-declared artifacts in trust-precedence order	rebuilt
Artifact-backed mental-model rebuild	Restored seat derives understanding from a packet rather than native runtime continuity	(case of rebuilt)
Fresh launch	New agent without prior continuity	fresh

These are load-bearing distinctions. Do NOT collapse fork into artifact-backed reentry; do NOT collapse rebuild into fork.