refactor(ai): rename flattened tool helper

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

@@ -1031,10 +1031,9 @@ const fromRequest = Effect.fn("AnthropicMessages.fromRequest")(function* (reques
   // messages. Tools live highest in the cache hierarchy, so when callers
   // over-mark we keep their tool hints and shed the message-tail ones first.
   const breakpoints = Cache.newBreakpoints(ANTHROPIC_BREAKPOINT_CAP)
-  const definitions = ProviderShared.toolDefinitions(request.tools)
-  const tools = definitions.length === 0 ? undefined : definitions.map((tool) => lowerTool(breakpoints, tool))
+  const tools = ProviderShared.flatTools(request.tools).map((tool) => lowerTool(breakpoints, tool))
   // Anthropic rejects tool_choice when tools are absent; "none" is only meaningful with tools present.
-  const toolChoice = tools === undefined || !request.toolChoice ? undefined : yield* lowerToolChoice(request.toolChoice)
+  const toolChoice = tools.length === 0 || !request.toolChoice ? undefined : yield* lowerToolChoice(request.toolChoice)
   const systemParts = request.system.filter((part) => part.text.length > 0)
   const system =
     systemParts.length === 0
@@ -1057,7 +1056,7 @@ const fromRequest = Effect.fn("AnthropicMessages.fromRequest")(function* (reques
     model: request.model.id,
     system,
     messages,
-    tools,
+    tools: tools.length === 0 ? undefined : tools,
     tool_choice: toolChoice,
     stream: true as const,
     max_tokens: maxTokens,

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

@@ -463,7 +463,7 @@ const applyThinkingBindingDefault = (request: LLMRequest, thinking: Readonly<Rec
 
 const fromRequest = Effect.fn("BedrockConverse.fromRequest")(function* (request: LLMRequest) {
   const toolChoice = request.toolChoice ? yield* lowerToolChoice(request.toolChoice) : undefined
-  const tools = ProviderShared.toolDefinitions(request.tools)
+  const tools = ProviderShared.flatTools(request.tools)
   const generation = request.generation
   const options = yield* decodeOptions(request.providerOptions ?? {})
   const maxTokens =

packages/ai/src/protocols/gemini.ts

@@ -438,7 +438,7 @@ const lowerMessages = Effect.fn("Gemini.lowerMessages")(function* (request: LLMR
 })
 
 const fromRequest = Effect.fn("Gemini.fromRequest")(function* (request: LLMRequest) {
-  const tools = ProviderShared.toolDefinitions(request.tools)
+  const tools = ProviderShared.flatTools(request.tools)
   const hasTools = tools.length > 0
   const generation = request.generation
   const options = yield* decodeOptions(request.providerOptions ?? {})

packages/ai/src/protocols/meta-messages.ts

@@ -26,7 +26,7 @@ const Body = Schema.Struct({
 })
 
 const fromRequest = Effect.fn("MetaMessages.fromRequest")(function* (request: LLMRequest) {
-  const tools = ProviderShared.toolDefinitions(request.tools)
+  const tools = ProviderShared.flatTools(request.tools)
   const body = yield* AnthropicMessages.protocol.body.from(request)
   return {
     ...body,

packages/ai/src/protocols/meta-responses.ts

@@ -67,7 +67,7 @@ const adapter = {
 
 const fromRequest = Effect.fn("MetaResponses.fromRequest")(function* (request: LLMRequest) {
   const key = request.model.route.providerMetadataKey ?? String(request.model.provider)
-  const tools = ProviderShared.toolDefinitions(request.tools)
+  const tools = ProviderShared.flatTools(request.tools)
   const projected = LLMRequest.update(request, {
     messages: request.messages.map((message) =>
       Message.make({

packages/ai/src/protocols/mistral-chat.ts

@@ -390,7 +390,7 @@ export const fromRequest = Effect.fn("MistralChat.fromRequest")(function* (reque
         tool: (name) => ({ type: "function" as const, function: { name } }),
       })
     : undefined
-  const tools = ProviderShared.toolDefinitions(request.tools)
+  const tools = ProviderShared.flatTools(request.tools)
   return {
     model: request.model.id,
     messages: yield* lowerMessages(request),

packages/ai/src/protocols/open-responses.ts

@@ -816,7 +816,7 @@ export const fromRequestWithAdapter = Effect.fn("OpenResponses.fromRequestWithAd
   request: LLMRequest,
   adapter: ProviderAdapter,
 ) {
-  const tools = ProviderShared.toolDefinitions(request.tools)
+  const tools = ProviderShared.flatTools(request.tools)
   return {
     ...(yield* lowerConversation(request, adapter)),
     ...lowerGeneration(request),

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

@@ -826,7 +826,7 @@ export const fromRequest = Effect.fn("OpenAIChat.fromRequest")(function* (
   const zaiToolStream =
     request.model.compatibility?.zaiToolStream ?? detectZaiToolStream(provider, baseURL, request.model.id)
   const hasHistory = hasToolHistory(request.messages)
-  const tools = ProviderShared.toolDefinitions(request.tools)
+  const tools = ProviderShared.flatTools(request.tools)
   const hasActiveTools = tools.length > 0
   return {
     model: request.model.id,

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

@@ -181,7 +181,7 @@ const lowerToolEntry = Effect.fn("OpenAIResponses.lowerToolEntry")(function* (to
     type: "namespace" as const,
     name: tool.name,
     description: tool.description ?? `Tools in the ${tool.name} namespace.`,
-    tools: yield* Effect.forEach(ProviderShared.toolDefinitions(tool.tools), (leaf) =>
+    tools: yield* Effect.forEach(ProviderShared.flatTools(tool.tools), (leaf) =>
       OpenResponses.lowerTool(NAME, leaf),
     ),
   }

packages/ai/src/protocols/shared.ts

@@ -287,11 +287,8 @@ export const unsupportedOperation = (input: {
     }),
   })
 
-/**
- * Tool definitions of a route-lowered request. The route flattens namespaces
- * before a flat protocol's `body.from`, so no namespace reaches this point.
- */
-export const toolDefinitions = (tools: ReadonlyArray<ToolEntry>) =>
+/** The route flattens namespaces before a flat protocol's `body.from`, so only plain tools remain. */
+export const flatTools = (tools: ReadonlyArray<ToolEntry>) =>
   tools.filter((tool): tool is ToolDefinition => tool.type === "tool")
 
 export const matchToolChoice = <Auto, None, Required, Tool>(

packages/ai/src/protocols/xai-responses.ts

@@ -95,7 +95,7 @@ export const protocol = Protocol.make({
 })
 
 export const compact = ResponsesCompaction.make(adapter, (request) =>
-  OpenResponses.lowerTools(ProviderShared.toolDefinitions(request.tools), adapter),
+  OpenResponses.lowerTools(ProviderShared.flatTools(request.tools), adapter),
 )
 
 export * as XAIResponses from "./xai-responses.js"

packages/core/src/aisdk.ts

@@ -487,7 +487,7 @@ function callOptions(
     presencePenalty: request.generation?.presencePenalty,
     frequencyPenalty: request.generation?.frequencyPenalty,
     seed: request.generation?.seed,
-    tools: ProviderShared.toolDefinitions(request.tools).map(tool),
+    tools: ProviderShared.flatTools(request.tools).map(tool),
     toolChoice: toolChoice(request.toolChoice),
     headers: request.http?.headers,
     providerOptions: requestProviderOptions(request.providerOptions, packageName, modelID, optionKey),