## Why
Compaction replaces the model history window, but host-verified user answers may
still be needed for the rest of the owning thread.
## What changed
- Add bounded, model-invisible retained context for verified
`request_user_input` answers.
- Persist retained context in rollout events and compaction checkpoints, and
restore it when a thread resumes.
- Remove answers when their source turns are rolled back, and prevent
parent-local answers from being inherited by child forks.
## Testing
Add lifecycle coverage for deduplication and size limits, compaction and resume,
rollback, rollout migration, and child forks.
GitOrigin-RevId: c32900d3e8120a9899b71f0576683acd67a4b898
## What changed
- Replace `send_user_message_async` with `request_user_input_async`, accepting one or more questions with optional suggested answers while allowing the turn to continue.
- Attach structured question metadata to asynchronous agent messages while retaining readable fallback text, and preserve it through app-server events, thread history, and generated schemas.
- Continue enabling the new tool for model catalogs that advertise either the old or new tool name.
## Testing
- Cover tool registration, question validation, emitted items, continued turn execution, history preservation, and backwards-compatible deserialization.
GitOrigin-RevId: ffc49aebde2e854c3c50a122aa52805fec3fc6b3
## Why
Guardian review evidence must remain available after a compacted thread is resumed or forked, while rolled-back or parent-local evidence must not grant authorization in a different context.
## What changed
- Store the bounded, model-invisible Guardian transcript alongside compacted rollout history and restore it from the newest surviving checkpoint during replay.
- Trim Guardian history at rollback boundaries, clearing it when the boundary has already been evicted.
- Preserve the checkpoint for user-initiated forks, but remove it when spawning a subagent so parent review evidence is not inherited.
- Keep the new rollout field optional for compatibility with existing compacted records and legacy readers.
## Testing
- Cover Guardian history across compaction, restart, paginated and pathless stores, user forks, rollback, bounded replay, serialization, and subagent forks.
GitOrigin-RevId: 6ab076d5e0c3aac4d6a41ebd50ba2b200c90213e
## Why
Resumed threads need to continue per-turn and per-thread token totals without scanning arbitrarily far beyond the latest compaction checkpoint.
## What changed
- Add durable `TokenUsageRecord` rollout items with response, turn, thread, session, and root-turn attribution.
- Restore accumulated usage on resume and snapshot the latest record plus the compaction response ID in compaction checkpoints.
- Preserve root-turn lineage in persisted turn context, while ensuring forked child threads start with their own usage totals.
## Testing
- Cover usage accumulation across multiple responses and resumed turns.
- Cover local and remote compaction checkpoints, invalid remote compaction output, rollout reconstruction, and fork isolation.
GitOrigin-RevId: ef9e0c4a9102a08a2c382be4cdac68c84353c90a
## What changed
- Add an optional `delivery` field to agent message events and app-server
`agentMessage` items, with `"async"` identifying a user-visible message sent
without ending the current turn.
- Preserve the marker through legacy event conversion, thread history
materialization, replay, and generated JSON and TypeScript schemas.
- Require delivery of async agent message completion notifications on the
in-process app-server transport.
## Testing
- Cover preservation of async delivery metadata in thread history.
- Cover delivery-required classification for async agent messages.
GitOrigin-RevId: f92ba25de1293ee271404badfdf0d117d6530329
## Why
Compaction can remove the tool-call events that associate an MCP app widget with
the tool, account, and URI needed to authorize later resource reads.
## What changed
- Store a bounded MCP resource-origin checkpoint with each compacted rollout.
- Restore the checkpoint when resuming a session so existing widgets remain
readable after compaction and restart.
- Discard saved origins when rollback rewrites history across the compaction
boundary, and reject oversized or invalid checkpoints during restoration.
## Testing
- Extend the app-server MCP resource-origin test to compact a paginated thread,
continue the conversation, and read the original widgets before and after a
restart.
- Verify rollback clears provenance that no longer matches retained history.
GitOrigin-RevId: 7f91c6202fe8d9be21c78dda42fa205937c44263
## Why
Building a resume-picker preview for a legacy session should not require loading its full thread history.
## What changed
- Read up to six preview lines by scanning at most 1 MiB from the end of a local legacy rollout.
- Fall back to the existing history hydration path when the local file is unavailable, the bounded scan is incomplete, or the tail contains a rollback.
- Keep the initial `thread/read` request turn-free while loading the preview.
## Testing
Added coverage for compaction, rollbacks, oversized records, exhausted scan budgets, and app-server request parameters.
GitOrigin-RevId: a8950f03d8b56323f268fd3355c6a38a16cb9833
## What changed
- Scan legacy and paginated transcript items newest-first and stop after collecting the six newest nonblank preview lines.
- Keep paging through bounded paginated history when newer items do not produce visible preview text, while preserving chronological display order and assistant markdown rewrites.
- Move transcript preview loading into a focused module and add coverage for reverse scanning, legacy/paginated parity, and paging past invisible items.
GitOrigin-RevId: 576afe37d034b32db363691bd4f401815fffaea7
felixxia-oai