When Cursor packs toolCallStarted and toolCallCompleted into one HTTP/2
chunk, the bridge tool_execution_end (synchronous callback, fired
mid-parse) reaches the interactive controller before the streamed
toolcall_start (queued on AssistantMessageEventStream, delivered a
microtask later). The controller found no pendingTools entry, dropped
the completion, and the card created afterwards animated forever.
Two halves, each necessary:
- Hold an early todo completion in #orphanedToolCompletions and replay
it when the streamed block creates its component.
- Guard card creation from cumulative message_update frames with the
turn-scoped #toolTimelineComponents map. Without this, the update
after the replay re-lists the same toolCall block, finds pendingTools
empty again, and spawns a second, permanently pending card. This is
also why emitting a synthetic tool_execution_start from the bridge
(previous attempt, reverted) could not work.
Both maps are cleared together at the existing transcript-anchor reset
sites. The normal ordering (start first) is covered by a control test.
Two review findings on the native todo sync.
- TodoItem.dependencies is a graph the local model cannot store: rows
are keyed by content, carry no id, and hold no edges. An imported
dependent row files as plain pending and nextActionableTask then
offers work the server considers blocked. Refuse snapshots with an
edge pointing at an unfinished row; edges whose blockers already
finished constrain nothing and still mirror.
- The todo failure warning interpolated the provider error verbatim.
Collapse and truncate it at the render boundary.
Also documents two known, unfixed defects: an async cursorOnToolResult
transformer resolving after the buffer drain, and the todo card
lifecycle race. Emitting a synthetic tool_execution_start for the
latter was measured and rejected -- the completion deletes the entry it
creates, so the late streamed block adds a second card.
Diogo Soares Rodrigues