[SDK post-0.1] Ship conversational control: create, send, stream, stop, retry, reconcile

[BunsDev]

Blocked by:

• [SDK 0.1.0][P0] Execute the first public release and validate registry provenance #41

Outcome

After the secure read-only release is validated, add the first bounded mutation authority: canonical conversation creation and idempotent send/stream control, with Cave remaining the sole executor and canonical state owner.

Required surface

• canonical conversation create/update/delete where approved;
• send with one caller-visible operation UUID;
• resumable typed stream with monotonic event IDs;
• stop;
• retry of an explicitly failed/cancelled turn with a fresh operation UUID;
• reconciliation when replay history is unavailable or canonical state moved.

Architectural invariants

• Cave owns persistent idempotency, execution, stop semantics, canonical mutations, and replay buffers.
• The SDK exposes constrained typed operations, never arbitrary HTTP paths or private Cave routes.
• An identical completed mutation may replay its recorded result; a reused key with a different canonical request hash is a conflict.
• An ambiguous transport completion never causes automatic mutation replay.
• Initial and resumed streams use the same event translator.
• Abort closes the current read; it does not retry the send.
• reconcile_required reloads canonical history rather than fabricating continuity.

Dependencies and blockers

• Stable released 0.1 read/discovery/pairing foundation
• Cave Client v1 idempotency and mutation routes
• Approved stream event contract and replay retention policy
• Real-authority conformance extension for mutation and restart behavior

Acceptance criteria

• Persistent idempotency survives authority restart and contains no prompt/attachment/bearer content beyond approved hashes and result metadata.
• Concurrent duplicate claims execute once.
• Same key/different request returns conflict.
• Send returns the operation ID on success and error.
• Stream resume emits only events after the supplied cursor and suppresses duplicates.
• Replay gaps produce reconcile_required.
• Stop and retry operate through canonical Cave services.
• Retry uses a fresh operation ID and explicit retryOfTurnId.
• Human/JSON/NDJSON CLI output preserves event order and never leaks private causes.
• Packed examples and real-authority mutation journeys pass.

Validation

Idempotency fault injection, stream framing/cursor tests, restart/replay conformance, duplicate-send mutations, packed consumer examples, and a separate security review for the new authority level.

Non-goals

Attachments, task handoffs, GitHub mutations, arbitrary tools, offline mutation queues, and private-route bridging remain out of scope.