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.

The three mechanisms — who owns each (verified vs main d37a08ad, 2026-07-21)

The outcomes above ride on three DISTINCT mechanisms; keep them separate:

1. Claude built-in /compact — a Claude Code HARNESS feature, not OpenRig code. OpenRig only emits the literal /compact toward the pane after a prep turn; there is no compaction algorithm in the OpenRig repo. Provider-owned.
2. OpenRig-managed restore — the enforcer + hook bridge: a precompact hook WRITES a restore packet; a bridge READER injects exactly ONE restore directive back via the harness hook channel (hookSpecificOutput.additionalContext), seat-isolated. The OpenRig-owned half.
3. Codex session continuity — resume/rollout tokens (codex resume <token>), a separate path from the Claude mechanisms. Never conflate with Claude restore.

Safety boundary (ties to native-session-file-lab-boundary): no supported OpenRig path EDITS provider-owned native session / auth / transcript files to inject context. Context enters ONLY through sanctioned channels: the hook additionalContext, a normal user message via rig send, or Codex resume tokens. Precise nuance: OpenRig does write ~/.codex/config.toml — but only to install OpenRig activity hooks and [features], never session or auth state. So the rule is "never edits native session/auth/transcript files," NOT "never touches any provider-owned file."

Current CLI surface (operator / kernel seats; verified vs main d37a08ad)

Managed compaction/restore is driven by five shipped verbs — pick per intent, and stay durable-substrate-first (the packet/artifacts are the truth; the CLI is the trigger):

• rig compact <session> — guided managed compaction for ONE Claude seat (prep → /compact → restore → audit). Non-Claude seats rejected. ~180s.
• rig compact-plan — READ-ONLY triage; does not compact. Flags --rig, --refresh, --threshold-tokens, --threshold-percent. (Codex seats flagged codex_not_managed_by_claude_compact_in_place.)
• rig restore-check — restore-readiness probe across running rigs; read-only; exit 0/1/2. Flags --full, --ready, --rig, --no-queue, --no-hooks.
• rig restore-packet {write,read,validate} — the cross-runtime restore packet (v0): write / read / validate the durable packet this skill's contract defines.
• rig restore <snapshotId> --rig <rigId> — ⚠ RIG SNAPSHOT restore (infra), a DIFFERENT mechanism — NOT session-context restore. Do not conflate.

Failure modes (4)

1. A compacted seat forgets active workflow state and drops the hot potato. Compaction without continuity preservation is silent failure.
2. A restore packet preserves details but loses the user's product intent. Restore must preserve why this work matters, not just what was happening.
3. A runtime resume is mistaken for a seat handover or fork. These have different continuity outcomes and provenance — don't conflate.
4. A rebuilt seat starts with stale instructions that conflict with current workflow mode. Restore must include current state, not just historical state.

Proof standard

Proof should include a deliberate compaction/restart of a seat with active work, followed by measured recovery: identity, current workflow, next owner, relevant files, and constraints all restored without human re-briefing.

Canonical packet contract (16-field, v0)

The cross-runtime restore/reentry packet standard v0 defines:

• Source/target identity
• Runtimes
• Workspace root, default repo, role pointer
• Bounded latest transcript
• Touched-path inventory
• Durable work pointers
• Current work + next owner
• Caveats + authority boundaries
• Omitted classes + redaction policy
• Source-trust ranking
• Generated-at + generator version

Plus a 6-item restored-seat acceptance checklist.

Source-trust ranking applies when restored seat ingests packet evidence: rig whoami > target rigspec > bounded latest transcript > full transcript > touched-files > restore-summary.json.

Memory surfaces consumed at restore time

A restore may consume transcripts, durable messages, startup context, checkpoints and a restore packet. Inventory the surfaces actually present for this seat, with their source, freshness and purpose. Do not infer that a named surface exists or grants write authority.

The active project/rig policy and task authorization determine what may be written. Treat provider-owned conversation records as evidence to read through supported tooling. For placement and durable context, load skills/openrig-operating-model/SKILL.md with rig context get; for the selected startup path, use skills/core/agent-startup-and-context-ingestion/SKILL.md. A packet or marker proves retained/delivered evidence, not successful provider restoration; measure the resumed seat against the proof standard above.

See also

• claude-compaction-restore skill — the Claude Code restore SOP (PreCompact hook + JSONL restore script for post-compaction recovery)
• mental-model-ha skill — HA-pair compaction recovery (different scenario; sister primitive)
• session-source-fork skill — fork mode for native-runtime-continuity-based restoration
• seat-continuity-and-handover skill — occupant-creation primitives (resume/fork/rebuild/fresh) that this primitive instantiates
• openrig-operating-model skill — placement and authority of durable context