COOL IDEAS™: distinguish checkpoint facts from declaration occurrences

[flyingrobots]

Classification

COOL IDEA™ — semantic/history model made visible by the real Echo-backed checkpoint slice.

Observation

Jim's checkpoint proposition is content-addressed by its semantics: worldline, basis head, and reason. Declaring the same proposition again therefore produces the same checkpoint identity.

Echo admission is a different fact of history. Each admitted request can have its own opaque receipt and admitted tick, including a re-declaration after restart.

Those are both truthful statements:

• “this semantic checkpoint is the same proposition”; and
• “the proposition was declared/admitted on these distinct occasions.”

A consumer that treats checkpoint ID as an event ID will collapse meaningful history. A consumer that treats every receipt as a new semantic checkpoint will fabricate duplicates.

Evidence

• Jim's checkpoint proposition fields
• Content-addressed checkpoint planning
• Restart/redeclaration witness retains checkpoint identity
• PR #282

The idea

Expose a bounded, Echo-backed observation that presents:

1. the stable Jim checkpoint proposition; and
2. the zero-or-more Echo admission occurrences that witness declarations of it.

Prefer deriving occurrences from Echo causal history, installed-operation receipts, and ticks. Add a separate Jim occurrence/association proposition only if the history model cannot answer the query without one.

Semantic questions to settle

• Does an identical request always receive a new admission occurrence, or may Echo return an idempotent/no-op outcome?
• What makes an occurrence discoverably associated with the checkpoint proposition?
• Which receipt/tick fields are stable public evidence versus internal scheduler detail?
• How are pruned or partially retained occurrences represented?
• Does a redeclaration after restart differ from replay recovery?
• What ordering is promised across worldlines, if any?

Constraints

• Do not change checkpoint proposition identity merely to make events look unique.
• Do not reproduce Echo digests or identity algorithms.
• Do not create a TypeScript event ledger or rely on process-local correlation maps.
• Runtime projections must reconstruct from Echo history/WAL after restart.
• A checkpoint remains distinct from a CausalAnchor.
• Missing or pruned evidence must be explicit, bounded, and typed.

Acceptance criteria

• Document checkpoint proposition identity separately from declaration-occurrence identity.
• Provide a bounded native observation keyed by opaque checkpoint ID.
• Return opaque Echo receipt/tick evidence for each retained occurrence.
• Distinguish first declaration, identical redeclaration, replay recovery, and unavailable/pruned history.
• Prove restart reconstruction without a process-local checkpoint→occurrence map.
• Prove repeated declarations do not mint fake checkpoint propositions.
• Give timeline consumers an unambiguous rule for grouping versus listing occurrences.
• Keep TypeScript as a projection/caller layer only.

Related, not duplicate

• COOL IDEAS™: expose an Echo-powered undo timeline #79 — timeline UI that can consume this model.
• Idempotent keystroke recovery through Echo WAL #86 — idempotent WAL recovery.
• Slice: Separate rope checkpoints from Echo anchor admission #220 — checkpoint versus anchor separation.
• Slice: End-to-end causal rope open edit save restart recovery #251 — end-to-end restart recovery.

[coderabbitai]

🔗 Related PRs

#23 - feat(echo): add Echo release gate witness [closed]
#195 - Add honest why observation coordinates [merged]
#265 - CR-01: Separate checkpoints from Echo anchor authority [merged]
#280 - Add runtime-backed causal range evidence [merged]
#282 - Route checkpoint declarations through Echo [merged]

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