feat(core): add embedded v2 session runtime and tool foundation (#30632)

packages/llm/src/protocols/gemini.ts

@@ -10,6 +10,7 @@ import {
   type FinishReason,
   type LLMRequest,
   type MediaPart,
+  type ProviderMetadata,
   type TextPart,
   type ToolCallPart,
   type ToolDefinition,
@@ -136,6 +137,7 @@ interface ParserState {
   readonly nextToolCallId: number
   readonly usage?: Usage
   readonly lifecycle: Lifecycle.State
+  readonly reasoningSignature?: string
 }
 
 const mediaData = ProviderShared.mediaBytes
@@ -181,14 +183,32 @@ const lowerToolConfig = (toolChoice: NonNullable<LLMRequest["toolChoice"]>) =>
 const lowerUserPart = (part: TextPart | MediaPart) =>
   part.type === "text" ? { text: part.text } : { inlineData: { mimeType: part.mediaType, data: mediaData(part) } }
 
+const googleMetadata = (metadata: Record<string, unknown>): ProviderMetadata => ({ google: metadata })
+
+const thoughtSignature = (providerMetadata: ProviderMetadata | undefined) => {
+  const google = providerMetadata?.google
+  return ProviderShared.isRecord(google) && typeof google.thoughtSignature === "string"
+    ? google.thoughtSignature
+    : undefined
+}
+
 const lowerToolCall = (part: ToolCallPart) => ({
   functionCall: { name: part.name, args: part.input },
+  thoughtSignature: thoughtSignature(part.providerMetadata),
 })
 
 const lowerMessages = Effect.fn("Gemini.lowerMessages")(function* (request: LLMRequest) {
   const contents: GeminiContent[] = []
 
   for (const message of request.messages) {
+    if (message.role === "system") {
+      const part = yield* ProviderShared.wrappedSystemUpdate("Gemini", message)
+      const previous = contents.at(-1)
+      if (previous?.role === "user") contents[contents.length - 1] = { role: "user", parts: [...previous.parts, { text: part.text }] }
+      else contents.push({ role: "user", parts: [{ text: part.text }] })
+      continue
+    }
+
     if (message.role === "user") {
       const parts: Array<Schema.Schema.Type<typeof GeminiContentPart>> = []
       for (const part of message.content) {
@@ -210,7 +230,7 @@ const lowerMessages = Effect.fn("Gemini.lowerMessages")(function* (request: LLMR
           continue
         }
         if (part.type === "reasoning") {
-          parts.push({ text: part.text, thought: true })
+          parts.push({ text: part.text, thought: true, thoughtSignature: thoughtSignature(part.providerMetadata) })
           continue
         }
         if (part.type === "tool-call") {
@@ -326,7 +346,15 @@ const finish = (state: ParserState): ReadonlyArray<LLMEvent> =>
   state.finishReason || state.usage
     ? (() => {
         const events: LLMEvent[] = []
-        Lifecycle.finish(state.lifecycle, events, {
+        const lifecycle = state.reasoningSignature
+          ? Lifecycle.reasoningEnd(
+              state.lifecycle,
+              events,
+              "reasoning-0",
+              googleMetadata({ thoughtSignature: state.reasoningSignature }),
+            )
+          : state.lifecycle
+        Lifecycle.finish(lifecycle, events, {
           reason: mapFinishReason(state.finishReason, state.hasToolCalls),
           usage: state.usage,
         })
@@ -350,11 +378,20 @@ const step = (state: ParserState, event: GeminiEvent) => {
   let hasToolCalls = nextState.hasToolCalls
   let lifecycle = nextState.lifecycle
   let nextToolCallId = nextState.nextToolCallId
+  let reasoningSignature = nextState.reasoningSignature
 
   for (const part of candidate.content.parts) {
+    if ("thoughtSignature" in part && part.thoughtSignature && "thought" in part && part.thought)
+      reasoningSignature = part.thoughtSignature
     if ("text" in part && part.text.length > 0) {
       lifecycle = part.thought
-        ? Lifecycle.reasoningDelta(lifecycle, events, "reasoning-0", part.text)
+        ? Lifecycle.reasoningDelta(
+            lifecycle,
+            events,
+            "reasoning-0",
+            part.text,
+            part.thoughtSignature ? googleMetadata({ thoughtSignature: part.thoughtSignature }) : undefined,
+          )
         : Lifecycle.textDelta(lifecycle, events, "text-0", part.text)
       continue
     }
@@ -363,7 +400,14 @@ const step = (state: ParserState, event: GeminiEvent) => {
       const input = part.functionCall.args
       const id = `tool_${nextToolCallId++}`
       lifecycle = Lifecycle.stepStart(lifecycle, events)
-      events.push(LLMEvent.toolCall({ id, name: part.functionCall.name, input }))
+      events.push(
+        LLMEvent.toolCall({
+          id,
+          name: part.functionCall.name,
+          input,
+          providerMetadata: part.thoughtSignature ? googleMetadata({ thoughtSignature: part.thoughtSignature }) : undefined,
+        }),
+      )
       hasToolCalls = true
     }
   }
@@ -374,6 +418,7 @@ const step = (state: ParserState, event: GeminiEvent) => {
       hasToolCalls,
       lifecycle,
       nextToolCallId,
+      reasoningSignature,
       finishReason: candidate.finishReason ?? nextState.finishReason,
     },
     events,