Emit LLM stream lifecycle events (#26971)

packages/llm/src/protocols/openai-chat.ts

@@ -16,6 +16,7 @@ import {
 } from "../schema"
 import { isRecord, JsonObject, optionalArray, optionalNull, ProviderShared } from "./shared"
 import { OpenAIOptions } from "./utils/openai-options"
+import { Lifecycle } from "./utils/lifecycle"
 import { ToolStream } from "./utils/tool-stream"
 
 const ADAPTER = "openai-chat"
@@ -147,6 +148,7 @@ interface ParserState {
   readonly toolCallEvents: ReadonlyArray<LLMEvent>
   readonly usage?: Usage
   readonly finishReason?: FinishReason
+  readonly lifecycle: Lifecycle.State
 }
 
 const invalid = ProviderShared.invalidRequest
@@ -321,7 +323,9 @@ const step = (state: ParserState, event: OpenAIChatEvent) =>
     const toolDeltas = delta?.tool_calls ?? []
     let tools = state.tools
 
-    if (delta?.content) events.push(LLMEvent.textDelta({ id: "text-0", text: delta.content }))
+    let lifecycle = state.lifecycle
+
+    if (delta?.content) lifecycle = Lifecycle.textDelta(lifecycle, events, "text-0", delta.content)
 
     for (const tool of toolDeltas) {
       const result = ToolStream.appendOrStart(
@@ -333,7 +337,8 @@ const step = (state: ParserState, event: OpenAIChatEvent) =>
       )
       if (ToolStream.isError(result)) return yield* result
       tools = result.tools
-      if (result.event) events.push(result.event)
+      if (result.events.length) lifecycle = Lifecycle.stepStart(lifecycle, events)
+      events.push(...result.events)
     }
 
     // Finalize accumulated tool inputs eagerly when finish_reason arrives so
@@ -349,15 +354,20 @@ const step = (state: ParserState, event: OpenAIChatEvent) =>
         toolCallEvents: finished?.events ?? state.toolCallEvents,
         usage,
         finishReason,
+        lifecycle,
       },
       events,
     ] as const
   })
 
 const finishEvents = (state: ParserState): ReadonlyArray<LLMEvent> => {
+  const events: LLMEvent[] = []
   const hasToolCalls = state.toolCallEvents.length > 0
   const reason = state.finishReason === "stop" && hasToolCalls ? "tool-calls" : state.finishReason
-  return [...state.toolCallEvents, ...(reason ? [LLMEvent.requestFinish({ reason, usage: state.usage })] : [])]
+  const lifecycle = state.toolCallEvents.length ? Lifecycle.stepStart(state.lifecycle, events) : state.lifecycle
+  events.push(...state.toolCallEvents)
+  if (reason) Lifecycle.finish(lifecycle, events, { reason, usage: state.usage })
+  return events
 }
 
 // =============================================================================
@@ -377,7 +387,7 @@ export const protocol = Protocol.make({
   },
   stream: {
     event: Protocol.jsonEvent(OpenAIChatEvent),
-    initial: () => ({ tools: ToolStream.empty<number>(), toolCallEvents: [] }),
+    initial: () => ({ tools: ToolStream.empty<number>(), toolCallEvents: [], lifecycle: Lifecycle.initial() }),
     step,
     onHalt: finishEvents,
   },