Replay (Counterfactual)

This skill spawns a parallel "what-if" timeline rooted at an existing mem_snapshots row. It does not modify mem_nodes, mem_bt_ratings, or mem_judgements. The branch is recorded in mem_replay_branches and surfaced in the cockpit's Replay tab.

When to invoke

• The user types /replay.
• The cockpit shows a branch_paused event the user disagrees with — replay lets them simulate the alternative path before deciding whether to call mcp__memory__resume_branch.
• Post-mortem after a missed preregistration: replay against the snapshot from before the prereg lock to inspect what the alternative hypothesis would have looked like.

Workflow

1. Pick the snapshot. If the user did not name one, list recent snapshots via the cockpit (snapshots are also visible from mcp__memory__snapshot outputs in earlier turns).
2. Phrase the counterfactual in one sentence. Examples:

• "Approve hyp_07 instead of pruning it"
• "Tighten preregistration alpha to 0.01 instead of 0.05"
• "Use seed budget 10 instead of 3 for hyp_03"

1. Call mcp__memory__replay_counterfactual(snapshot_id, counterfactual). Capture the returned branch_id.
2. Run any inspection / hypothetical analysis you need INSIDE the response (no Bash, no file writes). All conclusions must reference the branch_id so the cockpit can group them.
3. If the replay produces an actionable suggestion, write it as a cockpit_interventions row (kind=note) so the user can promote it later via mcp__memory__resume_branch. Do not flip statuses yourself.

Guardrails

• Read-only effect on the live graph. The MCP tool is implemented to refuse writes to mem_nodes from this path; you should refuse too.
• One replay = one counterfactual. If the user wants to compare three what-ifs, create three branches with separate branch_ids.
• The replay does not run new code. It does not call seed_perturb, query_heldout, or any model script. It is purely an inspection over already-recorded state.
• Replay branches accumulate; the cockpit lists the latest 20 newest-first. Older branches stay queryable via mcp__memory__list_replay_branches(limit=N).