Emit LLM stream lifecycle events (#26971)

packages/llm/src/protocols/anthropic-messages.ts

@@ -17,6 +17,7 @@ import {
 } from "../schema"
 import { JsonObject, optionalArray, optionalNull, ProviderShared } from "./shared"
 import * as Cache from "./utils/cache"
+import { Lifecycle } from "./utils/lifecycle"
 import { ToolStream } from "./utils/tool-stream"
 
 const ADAPTER = "anthropic-messages"
@@ -190,6 +191,7 @@ type AnthropicEvent = Schema.Schema.Type<typeof AnthropicEvent>
 interface ParserState {
   readonly tools: ToolStream.State<number>
   readonly usage?: Usage
+  readonly lifecycle: Lifecycle.State
 }
 
 const invalid = ProviderShared.invalidRequest
@@ -500,37 +502,45 @@ const onContentBlockStart = (state: ParserState, event: AnthropicEvent): StepRes
   if (!block) return [state, NO_EVENTS]
 
   if ((block.type === "tool_use" || block.type === "server_tool_use") && event.index !== undefined) {
+    const events: LLMEvent[] = []
+    const lifecycle = Lifecycle.stepStart(state.lifecycle, events)
     return [
       {
         ...state,
+        lifecycle,
         tools: ToolStream.start(state.tools, event.index, {
           id: block.id ?? String(event.index),
           name: block.name ?? "",
           providerExecuted: block.type === "server_tool_use",
         }),
       },
-      NO_EVENTS,
+      [...events, LLMEvent.toolInputStart({ id: block.id ?? String(event.index), name: block.name ?? "" })],
     ]
   }
 
   if (block.type === "text" && block.text) {
-    return [state, [LLMEvent.textDelta({ id: `text-${event.index ?? 0}`, text: block.text })]]
+    const events: LLMEvent[] = []
+    return [
+      { ...state, lifecycle: Lifecycle.textDelta(state.lifecycle, events, `text-${event.index ?? 0}`, block.text) },
+      events,
+    ]
   }
 
   if (block.type === "thinking" && block.thinking) {
+    const events: LLMEvent[] = []
     return [
-      state,
+      {
-      [
+        ...state,
-        LLMEvent.reasoningDelta({
+        lifecycle: Lifecycle.reasoningDelta(state.lifecycle, events, `reasoning-${event.index ?? 0}`, block.thinking),
-          id: `reasoning-${event.index ?? 0}`,
+      },
-          text: block.thinking,
+      events,
-        }),
-      ],
     ]
   }
 
   const result = serverToolResultEvent(block)
-  return [state, result ? [result] : NO_EVENTS]
+  if (!result) return [state, NO_EVENTS]
+  const events: LLMEvent[] = []
+  return [{ ...state, lifecycle: Lifecycle.stepStart(state.lifecycle, events) }, [...events, result]]
 }
 
 const onContentBlockDelta = Effect.fn("AnthropicMessages.onContentBlockDelta")(function* (
@@ -540,25 +550,37 @@ const onContentBlockDelta = Effect.fn("AnthropicMessages.onContentBlockDelta")(f
   const delta = event.delta
 
   if (delta?.type === "text_delta" && delta.text) {
-    return [state, [LLMEvent.textDelta({ id: `text-${event.index ?? 0}`, text: delta.text })]] satisfies StepResult
+    const events: LLMEvent[] = []
+    return [
+      { ...state, lifecycle: Lifecycle.textDelta(state.lifecycle, events, `text-${event.index ?? 0}`, delta.text) },
+      events,
+    ] satisfies StepResult
   }
 
   if (delta?.type === "thinking_delta" && delta.thinking) {
+    const events: LLMEvent[] = []
     return [
-      state,
+      {
-      [LLMEvent.reasoningDelta({ id: `reasoning-${event.index ?? 0}`, text: delta.thinking })],
+        ...state,
+        lifecycle: Lifecycle.reasoningDelta(state.lifecycle, events, `reasoning-${event.index ?? 0}`, delta.thinking),
+      },
+      events,
     ] satisfies StepResult
   }
 
   if (delta?.type === "signature_delta" && delta.signature) {
+    const events: LLMEvent[] = []
     return [
-      state,
+      {
-      [
+        ...state,
-        LLMEvent.reasoningEnd({
+        lifecycle: Lifecycle.reasoningEnd(
-          id: `reasoning-${event.index ?? 0}`,
+          state.lifecycle,
-          providerMetadata: anthropicMetadata({ signature: delta.signature }),
+          events,
-        }),
+          `reasoning-${event.index ?? 0}`,
-      ],
+          anthropicMetadata({ signature: delta.signature }),
+        ),
+      },
+      events,
     ] satisfies StepResult
   }
 
@@ -572,7 +594,10 @@ const onContentBlockDelta = Effect.fn("AnthropicMessages.onContentBlockDelta")(f
       "Anthropic Messages tool argument delta is missing its tool call",
     )
     if (ToolStream.isError(result)) return yield* result
-    return [{ ...state, tools: result.tools }, result.event ? [result.event] : NO_EVENTS] satisfies StepResult
+    const events: LLMEvent[] = []
+    const lifecycle = result.events.length ? Lifecycle.stepStart(state.lifecycle, events) : state.lifecycle
+    events.push(...result.events)
+    return [{ ...state, lifecycle, tools: result.tools }, events] satisfies StepResult
   }
 
   return [state, NO_EVENTS] satisfies StepResult
@@ -584,23 +609,30 @@ const onContentBlockStop = Effect.fn("AnthropicMessages.onContentBlockStop")(fun
 ) {
   if (event.index === undefined) return [state, NO_EVENTS] satisfies StepResult
   const result = yield* ToolStream.finish(ADAPTER, state.tools, event.index)
-  return [{ ...state, tools: result.tools }, result.event ? [result.event] : NO_EVENTS] satisfies StepResult
+  const events: LLMEvent[] = []
+  const resultEvents = result.events ?? []
+  const lifecycle = resultEvents.length
+    ? Lifecycle.stepStart(state.lifecycle, events)
+    : Lifecycle.reasoningEnd(
+        Lifecycle.textEnd(state.lifecycle, events, `text-${event.index}`),
+        events,
+        `reasoning-${event.index}`,
+      )
+  events.push(...resultEvents)
+  return [{ ...state, lifecycle, tools: result.tools }, events] satisfies StepResult
 })
 
 const onMessageDelta = (state: ParserState, event: AnthropicEvent): StepResult => {
   const usage = mergeUsage(state.usage, mapUsage(event.usage))
-  return [
+  const events: LLMEvent[] = []
-    { ...state, usage },
+  const lifecycle = Lifecycle.finish(state.lifecycle, events, {
-    [
+    reason: mapFinishReason(event.delta?.stop_reason),
-      LLMEvent.requestFinish({
+    usage,
-        reason: mapFinishReason(event.delta?.stop_reason),
+    providerMetadata: event.delta?.stop_sequence
-        usage,
+      ? anthropicMetadata({ stopSequence: event.delta.stop_sequence })
-        providerMetadata: event.delta?.stop_sequence
+      : undefined,
-          ? anthropicMetadata({ stopSequence: event.delta.stop_sequence })
+  })
-          : undefined,
+  return [{ ...state, lifecycle, usage }, events]
-      }),
-    ],
-  ]
 }
 
 const onError = (state: ParserState, event: AnthropicEvent): StepResult => [
@@ -634,7 +666,7 @@ export const protocol = Protocol.make({
   },
   stream: {
     event: Protocol.jsonEvent(AnthropicEvent),
-    initial: () => ({ tools: ToolStream.empty<number>() }),
+    initial: () => ({ tools: ToolStream.empty<number>(), lifecycle: Lifecycle.initial() }),
     step,
   },
 })

packages/llm/src/protocols/bedrock-converse.ts

@@ -17,6 +17,7 @@ import { JsonObject, optionalArray, ProviderShared } from "./shared"
 import { BedrockAuth, type Credentials as BedrockCredentials } from "./utils/bedrock-auth"
 import { BedrockCache } from "./utils/bedrock-cache"
 import { BedrockMedia } from "./utils/bedrock-media"
+import { Lifecycle } from "./utils/lifecycle"
 import { ToolStream } from "./utils/tool-stream"
 
 const ADAPTER = "bedrock-converse"
@@ -420,45 +421,64 @@ interface ParserState {
   // `metadata` (carries usage). Hold the terminal event in state so `onHalt`
   // can emit exactly one finish after both chunks have had a chance to arrive.
   readonly pendingFinish: { readonly reason: FinishReason; readonly usage?: Usage } | undefined
+  readonly hasToolCalls: boolean
+  readonly lifecycle: Lifecycle.State
 }
 
 const step = (state: ParserState, event: BedrockEvent) =>
   Effect.gen(function* () {
     if (event.contentBlockStart?.start?.toolUse) {
       const index = event.contentBlockStart.contentBlockIndex
+      const events: LLMEvent[] = []
+      const lifecycle = Lifecycle.stepStart(state.lifecycle, events)
       return [
         {
           ...state,
+          lifecycle,
           tools: ToolStream.start(state.tools, index, {
             id: event.contentBlockStart.start.toolUse.toolUseId,
             name: event.contentBlockStart.start.toolUse.name,
           }),
         },
-        [],
+        [
+          ...events,
+          LLMEvent.toolInputStart({
+            id: event.contentBlockStart.start.toolUse.toolUseId,
+            name: event.contentBlockStart.start.toolUse.name,
+          }),
+        ],
       ] as const
     }
 
     if (event.contentBlockDelta?.delta?.text) {
+      const events: LLMEvent[] = []
       return [
-        state,
+        {
-        [
+          ...state,
-          LLMEvent.textDelta({
+          lifecycle: Lifecycle.textDelta(
-            id: `text-${event.contentBlockDelta.contentBlockIndex}`,
+            state.lifecycle,
-            text: event.contentBlockDelta.delta.text,
+            events,
-          }),
+            `text-${event.contentBlockDelta.contentBlockIndex}`,
-        ],
+            event.contentBlockDelta.delta.text,
+          ),
+        },
+        events,
       ] as const
     }
 
     if (event.contentBlockDelta?.delta?.reasoningContent?.text) {
+      const events: LLMEvent[] = []
       return [
-        state,
+        {
-        [
+          ...state,
-          LLMEvent.reasoningDelta({
+          lifecycle: Lifecycle.reasoningDelta(
-            id: `reasoning-${event.contentBlockDelta.contentBlockIndex}`,
+            state.lifecycle,
-            text: event.contentBlockDelta.delta.reasoningContent.text,
+            events,
-          }),
+            `reasoning-${event.contentBlockDelta.contentBlockIndex}`,
-        ],
+            event.contentBlockDelta.delta.reasoningContent.text,
+          ),
+        },
+        events,
       ] as const
     }
 
@@ -472,12 +492,33 @@ const step = (state: ParserState, event: BedrockEvent) =>
         "Bedrock Converse tool delta is missing its tool call",
       )
       if (ToolStream.isError(result)) return yield* result
-      return [{ ...state, tools: result.tools }, result.event ? [result.event] : []] as const
+      const events: LLMEvent[] = []
+      const lifecycle = result.events.length ? Lifecycle.stepStart(state.lifecycle, events) : state.lifecycle
+      events.push(...result.events)
+      return [{ ...state, lifecycle, tools: result.tools }, events] as const
     }
 
     if (event.contentBlockStop) {
       const result = yield* ToolStream.finish(ADAPTER, state.tools, event.contentBlockStop.contentBlockIndex)
-      return [{ ...state, tools: result.tools }, result.event ? [result.event] : []] as const
+      const events: LLMEvent[] = []
+      const resultEvents = result.events ?? []
+      const lifecycle = resultEvents.length
+        ? Lifecycle.stepStart(state.lifecycle, events)
+        : Lifecycle.reasoningEnd(
+            Lifecycle.textEnd(state.lifecycle, events, `text-${event.contentBlockStop.contentBlockIndex}`),
+            events,
+            `reasoning-${event.contentBlockStop.contentBlockIndex}`,
+          )
+      events.push(...resultEvents)
+      return [
+        {
+          ...state,
+          hasToolCalls: resultEvents.some(LLMEvent.is.toolCall) ? true : state.hasToolCalls,
+          lifecycle,
+          tools: result.tools,
+        },
+        events,
+      ] as const
     }
 
     if (event.messageStop) {
@@ -517,7 +558,15 @@ const framing = BedrockEventStream.framing(ADAPTER)
 
 const onHalt = (state: ParserState): ReadonlyArray<LLMEvent> =>
   state.pendingFinish
-    ? [LLMEvent.requestFinish({ reason: state.pendingFinish.reason, usage: state.pendingFinish.usage })]
+    ? (() => {
+        const events: LLMEvent[] = []
+        Lifecycle.finish(state.lifecycle, events, {
+          reason:
+            state.pendingFinish.reason === "stop" && state.hasToolCalls ? "tool-calls" : state.pendingFinish.reason,
+          usage: state.pendingFinish.usage,
+        })
+        return events
+      })()
     : []
 
 // =============================================================================
@@ -535,7 +584,12 @@ export const protocol = Protocol.make({
   },
   stream: {
     event: BedrockEvent,
-    initial: () => ({ tools: ToolStream.empty<number>(), pendingFinish: undefined }),
+    initial: () => ({
+      tools: ToolStream.empty<number>(),
+      pendingFinish: undefined,
+      hasToolCalls: false,
+      lifecycle: Lifecycle.initial(),
+    }),
     step,
     onHalt,
   },

packages/llm/src/protocols/gemini.ts

@@ -16,6 +16,7 @@ import {
 } from "../schema"
 import { JsonObject, optionalArray, ProviderShared } from "./shared"
 import { GeminiToolSchema } from "./utils/gemini-tool-schema"
+import { Lifecycle } from "./utils/lifecycle"
 
 const ADAPTER = "gemini"
 export const DEFAULT_BASE_URL = "https://generativelanguage.googleapis.com/v1beta"
@@ -134,10 +135,9 @@ interface ParserState {
   readonly hasToolCalls: boolean
   readonly nextToolCallId: number
   readonly usage?: Usage
+  readonly lifecycle: Lifecycle.State
 }
 
-const invalid = ProviderShared.invalidRequest
-
 const mediaData = ProviderShared.mediaBytes
 
 // =============================================================================
@@ -324,7 +324,14 @@ const mapFinishReason = (finishReason: string | undefined, hasToolCalls: boolean
 
 const finish = (state: ParserState): ReadonlyArray<LLMEvent> =>
   state.finishReason || state.usage
-    ? [LLMEvent.requestFinish({ reason: mapFinishReason(state.finishReason, state.hasToolCalls), usage: state.usage })]
+    ? (() => {
+        const events: LLMEvent[] = []
+        Lifecycle.finish(state.lifecycle, events, {
+          reason: mapFinishReason(state.finishReason, state.hasToolCalls),
+          usage: state.usage,
+        })
+        return events
+      })()
     : []
 
 const step = (state: ParserState, event: GeminiEvent) => {
@@ -341,21 +348,21 @@ const step = (state: ParserState, event: GeminiEvent) => {
 
   const events: LLMEvent[] = []
   let hasToolCalls = nextState.hasToolCalls
+  let lifecycle = nextState.lifecycle
   let nextToolCallId = nextState.nextToolCallId
 
   for (const part of candidate.content.parts) {
     if ("text" in part && part.text.length > 0) {
-      events.push(
+      lifecycle = part.thought
-        part.thought
+        ? Lifecycle.reasoningDelta(lifecycle, events, "reasoning-0", part.text)
-          ? LLMEvent.reasoningDelta({ id: "reasoning-0", text: part.text })
+        : Lifecycle.textDelta(lifecycle, events, "text-0", part.text)
-          : LLMEvent.textDelta({ id: "text-0", text: part.text }),
-      )
       continue
     }
 
     if ("functionCall" in part) {
       const input = part.functionCall.args
       const id = `tool_${nextToolCallId++}`
+      lifecycle = Lifecycle.stepStart(lifecycle, events)
       events.push(LLMEvent.toolCall({ id, name: part.functionCall.name, input }))
       hasToolCalls = true
     }
@@ -365,6 +372,7 @@ const step = (state: ParserState, event: GeminiEvent) => {
     {
       ...nextState,
       hasToolCalls,
+      lifecycle,
       nextToolCallId,
       finishReason: candidate.finishReason ?? nextState.finishReason,
     },
@@ -388,7 +396,7 @@ export const protocol = Protocol.make({
   },
   stream: {
     event: Protocol.jsonEvent(GeminiEvent),
-    initial: () => ({ hasToolCalls: false, nextToolCallId: 0 }),
+    initial: () => ({ hasToolCalls: false, nextToolCallId: 0, lifecycle: Lifecycle.initial() }),
     step,
     onHalt: finish,
   },

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,
   },

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

@@ -17,6 +17,7 @@ import {
 } from "../schema"
 import { 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-responses"
@@ -165,6 +166,7 @@ type OpenAIResponsesEvent = Schema.Schema.Type<typeof OpenAIResponsesEvent>
 interface ParserState {
   readonly tools: ToolStream.State<string>
   readonly hasFunctionCall: boolean
+  readonly lifecycle: Lifecycle.State
 }
 
 const invalid = ProviderShared.invalidRequest
@@ -385,23 +387,32 @@ const TERMINAL_TYPES = new Set(["response.completed", "response.incomplete", "re
 
 const onOutputTextDelta = (state: ParserState, event: OpenAIResponsesEvent): StepResult => {
   if (!event.delta) return [state, NO_EVENTS]
-  return [state, [LLMEvent.textDelta({ id: event.item_id ?? "text-0", text: event.delta })]]
+  const events: LLMEvent[] = []
+  return [
+    { ...state, lifecycle: Lifecycle.textDelta(state.lifecycle, events, event.item_id ?? "text-0", event.delta) },
+    events,
+  ]
 }
 
 const onOutputItemAdded = (state: ParserState, event: OpenAIResponsesEvent): StepResult => {
   const item = event.item
   if (item?.type !== "function_call" || !item.id) return [state, NO_EVENTS]
+  const providerMetadata = openaiMetadata({ itemId: item.id })
+  const events: LLMEvent[] = []
+  const lifecycle = Lifecycle.stepStart(state.lifecycle, events)
   return [
     {
+      ...state,
+      lifecycle,
       hasFunctionCall: state.hasFunctionCall,
       tools: ToolStream.start(state.tools, item.id, {
         id: item.call_id ?? item.id,
         name: item.name ?? "",
         input: item.arguments ?? "",
-        providerMetadata: openaiMetadata({ itemId: item.id }),
+        providerMetadata,
       }),
     },
-    NO_EVENTS,
+    [...events, LLMEvent.toolInputStart({ id: item.call_id ?? item.id, name: item.name ?? "", providerMetadata })],
   ]
 }
 
@@ -418,10 +429,10 @@ const onFunctionCallArgumentsDelta = Effect.fn("OpenAIResponses.onFunctionCallAr
     "OpenAI Responses tool argument delta is missing its tool call",
   )
   if (ToolStream.isError(result)) return yield* result
-  return [
+  const events: LLMEvent[] = []
-    { hasFunctionCall: state.hasFunctionCall, tools: result.tools },
+  const lifecycle = result.events.length ? Lifecycle.stepStart(state.lifecycle, events) : state.lifecycle
-    result.event ? [result.event] : NO_EVENTS,
+  events.push(...result.events)
-  ] satisfies StepResult
+  return [{ ...state, lifecycle, tools: result.tools }, events] satisfies StepResult
 })
 
 const onOutputItemDone = Effect.fn("OpenAIResponses.onOutputItemDone")(function* (
@@ -440,33 +451,46 @@ const onOutputItemDone = Effect.fn("OpenAIResponses.onOutputItemDone")(function*
       item.arguments === undefined
         ? yield* ToolStream.finish(ADAPTER, tools, item.id)
         : yield* ToolStream.finishWithInput(ADAPTER, tools, item.id, item.arguments)
+    const events: LLMEvent[] = []
+    const resultEvents = result.events ?? []
+    const lifecycle = resultEvents.length ? Lifecycle.stepStart(state.lifecycle, events) : state.lifecycle
+    events.push(...resultEvents)
     return [
-      { hasFunctionCall: result.event ? true : state.hasFunctionCall, tools: result.tools },
+      {
-      result.event ? [result.event] : NO_EVENTS,
+        ...state,
+        lifecycle,
+        hasFunctionCall: resultEvents.some(LLMEvent.is.toolCall) ? true : state.hasFunctionCall,
+        tools: result.tools,
+      },
+      events,
     ] satisfies StepResult
   }
 
-  if (isHostedToolItem(item)) return [state, hostedToolEvents(item)] satisfies StepResult
+  if (isHostedToolItem(item)) {
+    const events: LLMEvent[] = []
+    const lifecycle = Lifecycle.stepStart(state.lifecycle, events)
+    events.push(...hostedToolEvents(item))
+    return [{ ...state, lifecycle }, events] satisfies StepResult
+  }
 
   return [state, NO_EVENTS] satisfies StepResult
 })
 
-const onResponseFinish = (state: ParserState, event: OpenAIResponsesEvent): StepResult => [
+const onResponseFinish = (state: ParserState, event: OpenAIResponsesEvent): StepResult => {
-  state,
+  const events: LLMEvent[] = []
-  [
+  const lifecycle = Lifecycle.finish(state.lifecycle, events, {
-    LLMEvent.requestFinish({
+    reason: mapFinishReason(event, state.hasFunctionCall),
-      reason: mapFinishReason(event, state.hasFunctionCall),
+    usage: mapUsage(event.response?.usage),
-      usage: mapUsage(event.response?.usage),
+    providerMetadata:
-      providerMetadata:
+      event.response?.id || event.response?.service_tier
-        event.response?.id || event.response?.service_tier
+        ? openaiMetadata({
-          ? openaiMetadata({
+            responseId: event.response.id,
-              responseId: event.response.id,
+            serviceTier: event.response.service_tier,
-              serviceTier: event.response.service_tier,
+          })
-            })
+        : undefined,
-          : undefined,
+  })
-    }),
+  return [{ ...state, lifecycle }, events]
-  ],
+}
-]
 
 const onResponseFailed = (state: ParserState, event: OpenAIResponsesEvent): StepResult => [
   state,
@@ -506,7 +530,7 @@ export const protocol = Protocol.make({
   },
   stream: {
     event: Protocol.jsonEvent(OpenAIResponsesEvent),
-    initial: () => ({ hasFunctionCall: false, tools: ToolStream.empty<string>() }),
+    initial: () => ({ hasFunctionCall: false, tools: ToolStream.empty<string>(), lifecycle: Lifecycle.initial() }),
     step,
     terminal: (event) => TERMINAL_TYPES.has(event.type),
   },

packages/llm/src/protocols/utils/lifecycle.ts

@@ -0,0 +1,88 @@
+import { LLMEvent, type FinishReason, type ProviderMetadata, type Usage } from "../../schema"
+
+export interface State {
+  readonly stepStarted: boolean
+  readonly text: ReadonlySet<string>
+  readonly reasoning: ReadonlySet<string>
+}
+
+export const initial = (): State => ({ stepStarted: false, text: new Set(), reasoning: new Set() })
+
+export const stepStart = (state: State, events: LLMEvent[]): State => {
+  if (state.stepStarted) return state
+  events.push(LLMEvent.stepStart({ index: 0 }))
+  return { ...state, stepStarted: true }
+}
+
+export const textDelta = (state: State, events: LLMEvent[], id: string, text: string): State => {
+  const stepped = stepStart(state, events)
+  if (stepped.text.has(id)) {
+    events.push(LLMEvent.textDelta({ id, text }))
+    return stepped
+  }
+  events.push(LLMEvent.textStart({ id }), LLMEvent.textDelta({ id, text }))
+  return { ...stepped, text: new Set([...stepped.text, id]) }
+}
+
+export const reasoningDelta = (state: State, events: LLMEvent[], id: string, text: string): State => {
+  const stepped = stepStart(state, events)
+  if (stepped.reasoning.has(id)) {
+    events.push(LLMEvent.reasoningDelta({ id, text }))
+    return stepped
+  }
+  events.push(LLMEvent.reasoningStart({ id }), LLMEvent.reasoningDelta({ id, text }))
+  return { ...stepped, reasoning: new Set([...stepped.reasoning, id]) }
+}
+
+export const reasoningEnd = (
+  state: State,
+  events: LLMEvent[],
+  id: string,
+  providerMetadata?: ProviderMetadata,
+): State => {
+  if (!state.reasoning.has(id)) return state
+  const stepped = stepStart(state, events)
+  events.push(LLMEvent.reasoningEnd({ id, providerMetadata }))
+  const reasoning = new Set(stepped.reasoning)
+  reasoning.delete(id)
+  return { ...stepped, reasoning }
+}
+
+export const textEnd = (state: State, events: LLMEvent[], id: string, providerMetadata?: ProviderMetadata): State => {
+  if (!state.text.has(id)) return state
+  const stepped = stepStart(state, events)
+  events.push(LLMEvent.textEnd({ id, providerMetadata }))
+  const text = new Set(stepped.text)
+  text.delete(id)
+  return { ...stepped, text }
+}
+
+const closeOpenBlocks = (state: State, events: LLMEvent[]): State => {
+  for (const id of state.reasoning) events.push(LLMEvent.reasoningEnd({ id }))
+  for (const id of state.text) events.push(LLMEvent.textEnd({ id }))
+  return { ...state, text: new Set(), reasoning: new Set() }
+}
+
+export const finish = (
+  state: State,
+  events: LLMEvent[],
+  input: {
+    readonly reason: FinishReason
+    readonly usage?: Usage
+    readonly providerMetadata?: ProviderMetadata
+  },
+): State => {
+  const stepped = closeOpenBlocks(stepStart(state, events), events)
+  events.push(
+    LLMEvent.stepFinish({
+      index: 0,
+      reason: input.reason,
+      usage: input.usage,
+      providerMetadata: input.providerMetadata,
+    }),
+    LLMEvent.requestFinish(input),
+  )
+  return { ...stepped, stepStarted: false }
+}
+
+export * as Lifecycle from "./lifecycle"

packages/llm/src/protocols/utils/tool-stream.ts

@@ -1,5 +1,5 @@
 import { Effect } from "effect"
-import { LLMError, LLMEvent, type ProviderMetadata, type ToolCall, type ToolInputDelta } from "../../schema"
+import { LLMError, LLMEvent, type ProviderMetadata, type ToolCall } from "../../schema"
 import { eventError, parseToolInput, type ToolAccumulator } from "../shared"
 
 type StreamKey = string | number
@@ -27,13 +27,13 @@ export type State<K extends StreamKey> = Partial<Record<K, PendingTool>>
 /**
  * Result of adding argument text to one pending tool call. It returns both the
  * next `tools` state and the updated `tool` because parsers often need the
- * current id/name immediately. `event` is present only when new text arrived;
+ * current id/name immediately. `events` contains lifecycle and delta events
- * metadata-only deltas update identity without emitting `tool-input-delta`.
+ * produced by the append; metadata-only deltas update identity without output.
  */
 export interface AppendOutcome<K extends StreamKey> {
   readonly tools: State<K>
   readonly tool: PendingTool
-  readonly event?: ToolInputDelta
+  readonly events: ReadonlyArray<LLMEvent>
 }
 
 /** Create empty accumulator state for one provider stream. */
@@ -49,7 +49,14 @@ const withoutTool = <K extends StreamKey>(tools: State<K>, key: K): State<K> =>
   return next
 }
 
-const inputDelta = (tool: PendingTool, text: string): ToolInputDelta =>
+const inputStart = (tool: PendingTool) =>
+  LLMEvent.toolInputStart({
+    id: tool.id,
+    name: tool.name,
+    providerMetadata: tool.providerMetadata,
+  })
+
+const inputDelta = (tool: PendingTool, text: string) =>
   LLMEvent.toolInputDelta({
     id: tool.id,
     name: tool.name,
@@ -76,11 +83,16 @@ const appendTool = <K extends StreamKey>(
   key: K,
   tool: PendingTool,
   text: string,
-): AppendOutcome<K> => ({
+): AppendOutcome<K> => {
-  tools: withTool(tools, key, tool),
+  const events: LLMEvent[] = []
-  tool,
+  if (!tools[key]) events.push(inputStart(tool))
-  event: text.length === 0 ? undefined : inputDelta(tool, text),
+  if (text.length > 0) events.push(inputDelta(tool, text))
-})
+  return {
+    tools: withTool(tools, key, tool),
+    tool,
+    events,
+  }
+}
 
 export const isError = <K extends StreamKey>(result: AppendOutcome<K> | LLMError): result is LLMError =>
   result instanceof LLMError
@@ -121,7 +133,8 @@ export const appendOrStart = <K extends StreamKey>(
     providerExecuted: current?.providerExecuted,
     providerMetadata: current?.providerMetadata,
   }
-  if (current && delta.text.length === 0 && current.id === id && current.name === name) return { tools, tool: current }
+  if (current && delta.text.length === 0 && current.id === id && current.name === name)
+    return { tools, tool: current, events: [] }
   return appendTool(tools, key, tool, delta.text)
 }
 
@@ -139,7 +152,7 @@ export const appendExisting = <K extends StreamKey>(
 ): AppendOutcome<K> | LLMError => {
   const current = tools[key]
   if (!current) return eventError(route, missingToolMessage)
-  if (text.length === 0) return { tools, tool: current }
+  if (text.length === 0) return { tools, tool: current, events: [] }
   return appendTool(tools, key, { ...current, input: `${current.input}${text}` }, text)
 }
 
@@ -152,7 +165,13 @@ export const finish = <K extends StreamKey>(route: string, tools: State<K>, key:
   Effect.gen(function* () {
     const tool = tools[key]
     if (!tool) return { tools }
-    return { tools: withoutTool(tools, key), event: yield* toolCall(route, tool) }
+    return {
+      tools: withoutTool(tools, key),
+      events: [
+        LLMEvent.toolInputEnd({ id: tool.id, name: tool.name, providerMetadata: tool.providerMetadata }),
+        yield* toolCall(route, tool),
+      ],
+    }
   })
 
 /**
@@ -164,7 +183,13 @@ export const finishWithInput = <K extends StreamKey>(route: string, tools: State
   Effect.gen(function* () {
     const tool = tools[key]
     if (!tool) return { tools }
-    return { tools: withoutTool(tools, key), event: yield* toolCall(route, tool, input) }
+    return {
+      tools: withoutTool(tools, key),
+      events: [
+        LLMEvent.toolInputEnd({ id: tool.id, name: tool.name, providerMetadata: tool.providerMetadata }),
+        yield* toolCall(route, tool, input),
+      ],
+    }
   })
 
 /**
@@ -179,7 +204,14 @@ export const finishAll = <K extends StreamKey>(route: string, tools: State<K>) =
     )
     return {
       tools: empty<K>(),
-      events: yield* Effect.forEach(pending, (tool) => toolCall(route, tool)),
+      events: yield* Effect.forEach(pending, (tool) =>
+        toolCall(route, tool).pipe(
+          Effect.map((call) => [
+            LLMEvent.toolInputEnd({ id: tool.id, name: tool.name, providerMetadata: tool.providerMetadata }),
+            call,
+          ]),
+        ),
+      ).pipe(Effect.map((events) => events.flat())),
     }
   })
 

packages/llm/src/tool-runtime.ts

@@ -154,8 +154,8 @@ const accumulate = (state: StepState, event: LLMEvent) => {
     )
     return
   }
-  if (event.type === "request-finish") {
+  if (event.type === "step-finish" || event.type === "request-finish") {
-    state.finishReason = event.reason
+    state.finishReason = event.reason === "stop" && state.toolCalls.length > 0 ? "tool-calls" : event.reason
   }
 }
 

packages/llm/test/provider/anthropic-messages.test.ts

@@ -146,24 +146,46 @@ describe("Anthropic Messages route", () => {
           tools: [{ name: "lookup", description: "Lookup data", inputSchema: { type: "object" } }],
         }),
       ).pipe(Effect.provide(fixedResponse(body)))
+      const usage = new Usage({
+        inputTokens: 5,
+        outputTokens: 1,
+        nonCachedInputTokens: 5,
+        cacheReadInputTokens: undefined,
+        cacheWriteInputTokens: undefined,
+        totalTokens: 6,
+        providerMetadata: { anthropic: { input_tokens: 5, output_tokens: 1 } },
+      })
 
       expect(response.toolCalls).toEqual([
-        { type: "tool-call", id: "call_1", name: "lookup", input: { query: "weather" } },
+        {
+          type: "tool-call",
+          id: "call_1",
+          name: "lookup",
+          input: { query: "weather" },
+          providerExecuted: undefined,
+          providerMetadata: undefined,
+        },
       ])
       expect(response.events).toEqual([
+        { type: "step-start", index: 0 },
+        { type: "tool-input-start", id: "call_1", name: "lookup" },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: '{"query"' },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: ':"weather"}' },
-        { type: "tool-call", id: "call_1", name: "lookup", input: { query: "weather" } },
+        { type: "tool-input-end", id: "call_1", name: "lookup", providerMetadata: undefined },
+        {
+          type: "tool-call",
+          id: "call_1",
+          name: "lookup",
+          input: { query: "weather" },
+          providerExecuted: undefined,
+          providerMetadata: undefined,
+        },
+        { type: "step-finish", index: 0, reason: "tool-calls", usage, providerMetadata: undefined },
         {
           type: "request-finish",
           reason: "tool-calls",
-          usage: new Usage({
+          providerMetadata: undefined,
-            inputTokens: 5,
+          usage,
-            outputTokens: 1,
-            nonCachedInputTokens: 5,
-            totalTokens: 6,
-            providerMetadata: { anthropic: { input_tokens: 5, output_tokens: 1 } },
-          }),
         },
       ])
     }),

packages/llm/test/provider/gemini.test.ts

@@ -204,30 +204,37 @@ describe("Gemini route", () => {
         reasoningTokens: 1,
         totalTokens: 7,
       })
+      const usage = new Usage({
+        inputTokens: 5,
+        outputTokens: 3,
+        nonCachedInputTokens: 4,
+        cacheReadInputTokens: 1,
+        reasoningTokens: 1,
+        totalTokens: 7,
+        providerMetadata: {
+          google: {
+            promptTokenCount: 5,
+            candidatesTokenCount: 2,
+            totalTokenCount: 7,
+            thoughtsTokenCount: 1,
+            cachedContentTokenCount: 1,
+          },
+        },
+      })
       expect(response.events).toEqual([
+        { type: "step-start", index: 0 },
+        { type: "reasoning-start", id: "reasoning-0" },
         { type: "reasoning-delta", id: "reasoning-0", text: "thinking" },
+        { type: "text-start", id: "text-0" },
         { type: "text-delta", id: "text-0", text: "Hello" },
         { type: "text-delta", id: "text-0", text: "!" },
+        { type: "reasoning-end", id: "reasoning-0" },
+        { type: "text-end", id: "text-0" },
+        { type: "step-finish", index: 0, reason: "stop", usage, providerMetadata: undefined },
         {
           type: "request-finish",
           reason: "stop",
-          usage: new Usage({
+          usage,
-            inputTokens: 5,
-            outputTokens: 3,
-            nonCachedInputTokens: 4,
-            cacheReadInputTokens: 1,
-            reasoningTokens: 1,
-            totalTokens: 7,
-            providerMetadata: {
-              google: {
-                promptTokenCount: 5,
-                candidatesTokenCount: 2,
-                totalTokenCount: 7,
-                thoughtsTokenCount: 1,
-                cachedContentTokenCount: 1,
-              },
-            },
-          }),
         },
       ])
     }),
@@ -252,22 +259,41 @@ describe("Gemini route", () => {
           tools: [{ name: "lookup", description: "Lookup data", inputSchema: { type: "object" } }],
         }),
       ).pipe(Effect.provide(fixedResponse(body)))
+      const usage = new Usage({
+        inputTokens: 5,
+        outputTokens: 1,
+        nonCachedInputTokens: 5,
+        cacheReadInputTokens: undefined,
+        reasoningTokens: undefined,
+        totalTokens: 6,
+        providerMetadata: { google: { promptTokenCount: 5, candidatesTokenCount: 1 } },
+      })
 
       expect(response.toolCalls).toEqual([
-        { type: "tool-call", id: "tool_0", name: "lookup", input: { query: "weather" } },
+        {
+          type: "tool-call",
+          id: "tool_0",
+          name: "lookup",
+          input: { query: "weather" },
+          providerExecuted: undefined,
+          providerMetadata: undefined,
+        },
       ])
       expect(response.events).toEqual([
-        { type: "tool-call", id: "tool_0", name: "lookup", input: { query: "weather" } },
+        { type: "step-start", index: 0 },
+        {
+          type: "tool-call",
+          id: "tool_0",
+          name: "lookup",
+          input: { query: "weather" },
+          providerExecuted: undefined,
+          providerMetadata: undefined,
+        },
+        { type: "step-finish", index: 0, reason: "tool-calls", usage, providerMetadata: undefined },
         {
           type: "request-finish",
           reason: "tool-calls",
-          usage: new Usage({
+          usage,
-            inputTokens: 5,
-            outputTokens: 1,
-            nonCachedInputTokens: 5,
-            totalTokens: 6,
-            providerMetadata: { google: { promptTokenCount: 5, candidatesTokenCount: 1 } },
-          }),
         },
       ])
     }),
@@ -318,8 +344,10 @@ describe("Gemini route", () => {
         ),
       )
 
-      expect(length.events).toEqual([{ type: "request-finish", reason: "length" }])
+      expect(length.events.map((event) => event.type)).toEqual(["step-start", "step-finish", "request-finish"])
-      expect(filtered.events).toEqual([{ type: "request-finish", reason: "content-filter" }])
+      expect(length.events.at(-1)).toMatchObject({ type: "request-finish", reason: "length" })
+      expect(filtered.events.map((event) => event.type)).toEqual(["step-start", "step-finish", "request-finish"])
+      expect(filtered.events.at(-1)).toMatchObject({ type: "request-finish", reason: "content-filter" })
     }),
   )
 

packages/llm/test/provider/openai-chat.test.ts

@@ -222,31 +222,36 @@ describe("OpenAI Chat route", () => {
         }),
       )
       const response = yield* LLMClient.generate(request).pipe(Effect.provide(fixedResponse(body)))
+      const usage = new Usage({
+        inputTokens: 5,
+        outputTokens: 2,
+        nonCachedInputTokens: 4,
+        cacheReadInputTokens: 1,
+        reasoningTokens: 0,
+        totalTokens: 7,
+        providerMetadata: {
+          openai: {
+            prompt_tokens: 5,
+            completion_tokens: 2,
+            total_tokens: 7,
+            prompt_tokens_details: { cached_tokens: 1 },
+            completion_tokens_details: { reasoning_tokens: 0 },
+          },
+        },
+      })
 
       expect(response.text).toBe("Hello!")
       expect(response.events).toEqual([
+        { type: "step-start", index: 0 },
+        { type: "text-start", id: "text-0" },
         { type: "text-delta", id: "text-0", text: "Hello" },
         { type: "text-delta", id: "text-0", text: "!" },
+        { type: "text-end", id: "text-0" },
+        { type: "step-finish", index: 0, reason: "stop", usage, providerMetadata: undefined },
         {
           type: "request-finish",
           reason: "stop",
-          usage: new Usage({
+          usage,
-            inputTokens: 5,
-            outputTokens: 2,
-            nonCachedInputTokens: 4,
-            cacheReadInputTokens: 1,
-            reasoningTokens: 0,
-            totalTokens: 7,
-            providerMetadata: {
-              openai: {
-                prompt_tokens: 5,
-                completion_tokens: 2,
-                total_tokens: 7,
-                prompt_tokens_details: { cached_tokens: 1 },
-                completion_tokens_details: { reasoning_tokens: 0 },
-              },
-            },
-          }),
         },
       ])
     }),
@@ -269,9 +274,20 @@ describe("OpenAI Chat route", () => {
       ).pipe(Effect.provide(fixedResponse(body)))
 
       expect(response.events).toEqual([
+        { type: "step-start", index: 0 },
+        { type: "tool-input-start", id: "call_1", name: "lookup", providerMetadata: undefined },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: '{"query"' },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: ':"weather"}' },
-        { type: "tool-call", id: "call_1", name: "lookup", input: { query: "weather" } },
+        { type: "tool-input-end", id: "call_1", name: "lookup", providerMetadata: undefined },
+        {
+          type: "tool-call",
+          id: "call_1",
+          name: "lookup",
+          input: { query: "weather" },
+          providerExecuted: undefined,
+          providerMetadata: undefined,
+        },
+        { type: "step-finish", index: 0, reason: "tool-calls", usage: undefined, providerMetadata: undefined },
         { type: "request-finish", reason: "tool-calls", usage: undefined },
       ])
     }),
@@ -293,6 +309,8 @@ describe("OpenAI Chat route", () => {
       ).pipe(Effect.provide(fixedResponse(body)))
 
       expect(response.events).toEqual([
+        { type: "step-start", index: 0 },
+        { type: "tool-input-start", id: "call_1", name: "lookup", providerMetadata: undefined },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: '{"query"' },
         { type: "tool-input-delta", id: "call_1", name: "lookup", text: ':"weather"}' },
       ])
@@ -352,7 +370,7 @@ describe("OpenAI Chat route", () => {
       const events = Array.from(
         yield* LLMClient.stream(request).pipe(Stream.take(1), Stream.runCollect, Effect.provide(fixedResponse(body))),
       )
-      expect(events.map((event) => event.type)).toEqual(["text-delta"])
+      expect(events.map((event) => event.type)).toEqual(["step-start"])
     }),
   )
 })

packages/llm/test/provider/openai-responses.test.ts

@@ -333,32 +333,43 @@ describe("OpenAI Responses route", () => {
         },
       )
       const response = yield* LLMClient.generate(request).pipe(Effect.provide(fixedResponse(body)))
+      const usage = new Usage({
+        inputTokens: 5,
+        outputTokens: 2,
+        nonCachedInputTokens: 4,
+        cacheReadInputTokens: 1,
+        reasoningTokens: 0,
+        totalTokens: 7,
+        providerMetadata: {
+          openai: {
+            input_tokens: 5,
+            output_tokens: 2,
+            total_tokens: 7,
+            input_tokens_details: { cached_tokens: 1 },
+            output_tokens_details: { reasoning_tokens: 0 },
+          },
+        },
+      })
 
       expect(response.text).toBe("Hello!")
       expect(response.events).toEqual([
+        { type: "step-start", index: 0 },
+        { type: "text-start", id: "msg_1" },
         { type: "text-delta", id: "msg_1", text: "Hello" },
         { type: "text-delta", id: "msg_1", text: "!" },
+        { type: "text-end", id: "msg_1" },
+        {
+          type: "step-finish",
+          index: 0,
+          reason: "stop",
+          providerMetadata: { openai: { responseId: "resp_1", serviceTier: "default" } },
+          usage,
+        },
         {
           type: "request-finish",
           reason: "stop",
           providerMetadata: { openai: { responseId: "resp_1", serviceTier: "default" } },
-          usage: new Usage({
+          usage,
-            inputTokens: 5,
-            outputTokens: 2,
-            nonCachedInputTokens: 4,
-            cacheReadInputTokens: 1,
-            reasoningTokens: 0,
-            totalTokens: 7,
-            providerMetadata: {
-              openai: {
-                input_tokens: 5,
-                output_tokens: 2,
-                total_tokens: 7,
-                input_tokens_details: { cached_tokens: 1 },
-                output_tokens_details: { reasoning_tokens: 0 },
-              },
-            },
-          }),
         },
       ])
     }),
@@ -390,8 +401,24 @@ describe("OpenAI Responses route", () => {
           tools: [{ name: "lookup", description: "Lookup data", inputSchema: { type: "object" } }],
         }),
       ).pipe(Effect.provide(fixedResponse(body)))
+      const usage = new Usage({
+        inputTokens: 5,
+        outputTokens: 1,
+        nonCachedInputTokens: 5,
+        cacheReadInputTokens: undefined,
+        reasoningTokens: undefined,
+        totalTokens: 6,
+        providerMetadata: { openai: { input_tokens: 5, output_tokens: 1 } },
+      })
 
       expect(response.events).toEqual([
+        { type: "step-start", index: 0 },
+        {
+          type: "tool-input-start",
+          id: "call_1",
+          name: "lookup",
+          providerMetadata: { openai: { itemId: "item_1" } },
+        },
         {
           type: "tool-input-delta",
           id: "call_1",
@@ -404,23 +431,26 @@ describe("OpenAI Responses route", () => {
           name: "lookup",
           text: ':"weather"}',
         },
+        {
+          type: "tool-input-end",
+          id: "call_1",
+          name: "lookup",
+          providerMetadata: { openai: { itemId: "item_1" } },
+        },
         {
           type: "tool-call",
           id: "call_1",
           name: "lookup",
           input: { query: "weather" },
+          providerExecuted: undefined,
           providerMetadata: { openai: { itemId: "item_1" } },
         },
+        { type: "step-finish", index: 0, reason: "tool-calls", usage, providerMetadata: undefined },
         {
           type: "request-finish",
           reason: "tool-calls",
-          usage: new Usage({
+          providerMetadata: undefined,
-            inputTokens: 5,
+          usage,
-            outputTokens: 1,
-            nonCachedInputTokens: 5,
-            totalTokens: 6,
-            providerMetadata: { openai: { input_tokens: 5, output_tokens: 1 } },
-          }),
         },
       ])
     }),

packages/llm/test/tool-runtime.test.ts

@@ -313,7 +313,14 @@ describe("LLMClient tools", () => {
         ),
       )
 
-      expect(events.map((event) => event.type)).toEqual(["text-delta", "request-finish"])
+      expect(events.map((event) => event.type)).toEqual([
+        "step-start",
+        "text-start",
+        "text-delta",
+        "text-end",
+        "step-finish",
+        "request-finish",
+      ])
       expect(LLMResponse.text({ events })).toBe("Done.")
     }),
   )

packages/llm/test/tool-stream.test.ts

@@ -21,11 +21,17 @@ describe("ToolStream", () => {
       if (ToolStream.isError(second)) return yield* second
       const finished = yield* ToolStream.finish(ADAPTER, second.tools, 0)
 
-      expect(first.event).toEqual({ type: "tool-input-delta", id: "call_1", name: "lookup", text: '{"query"' })
+      expect(first.events).toEqual([
-      expect(second.event).toEqual({ type: "tool-input-delta", id: "call_1", name: "lookup", text: ':"weather"}' })
+        { type: "tool-input-start", id: "call_1", name: "lookup" },
+        { type: "tool-input-delta", id: "call_1", name: "lookup", text: '{"query"' },
+      ])
+      expect(second.events).toEqual([{ type: "tool-input-delta", id: "call_1", name: "lookup", text: ':"weather"}' }])
       expect(finished).toEqual({
         tools: {},
-        event: { type: "tool-call", id: "call_1", name: "lookup", input: { query: "weather" } },
+        events: [
+          { type: "tool-input-end", id: "call_1", name: "lookup" },
+          { type: "tool-call", id: "call_1", name: "lookup", input: { query: "weather" } },
+        ],
       })
     }),
   )
@@ -50,7 +56,10 @@ describe("ToolStream", () => {
 
       expect(finished).toEqual({
         tools: {},
-        event: { type: "tool-call", id: "call_1", name: "lookup", input: { query: "final" } },
+        events: [
+          { type: "tool-input-end", id: "call_1", name: "lookup" },
+          { type: "tool-call", id: "call_1", name: "lookup", input: { query: "final" } },
+        ],
       })
     }),
   )
@@ -73,7 +82,9 @@ describe("ToolStream", () => {
       expect(finished).toEqual({
         tools: {},
         events: [
+          { type: "tool-input-end", id: "call_1", name: "lookup" },
           { type: "tool-call", id: "call_1", name: "lookup", input: {} },
+          { type: "tool-input-end", id: "call_2", name: "web_search" },
           {
             type: "tool-call",
             id: "call_2",