diff --git a/packages/ai/src/llm.ts b/packages/ai/src/llm.ts
index e4781d8608b..ecdf30ae47d 100644
--- a/packages/ai/src/llm.ts
+++ b/packages/ai/src/llm.ts
@@ -81,7 +81,7 @@ const GENERATE_OBJECT_TOOL_NAME = "generate_object"
 
 const GENERATE_OBJECT_TOOL_DESCRIPTION = "Return the structured result by calling this tool."
 
-type GenerateObjectBase = Omit<RequestInput, "tools" | "toolChoice" | "responseFormat">
+type GenerateObjectBase = Omit<RequestInput, "tools" | "toolChoice">
 
 export class GenerateObjectResponse<T> {
   constructor(
diff --git a/packages/ai/src/schema/messages.ts b/packages/ai/src/schema/messages.ts
index 4a9de3a735e..e6617ddc9ed 100644
--- a/packages/ai/src/schema/messages.ts
+++ b/packages/ai/src/schema/messages.ts
@@ -261,13 +261,6 @@ export namespace ToolChoice {
   }
 }
 
-export const ResponseFormat = Schema.Union([
-  Schema.Struct({ type: Schema.Literal("text") }),
-  Schema.Struct({ type: Schema.Literal("json"), schema: JsonSchema }),
-  Schema.Struct({ type: Schema.Literal("tool"), tool: ToolDefinition }),
-]).pipe(Schema.toTaggedUnion("type"))
-export type ResponseFormat = Schema.Schema.Type<typeof ResponseFormat>
-
 export class LLMRequest extends Schema.Class<LLMRequest>("LLM.Request")({
   id: Schema.optional(Schema.String),
   model: ModelSchema,
@@ -278,7 +271,6 @@ export class LLMRequest extends Schema.Class<LLMRequest>("LLM.Request")({
   generation: Schema.optional(GenerationOptions),
   providerOptions: Schema.optional(ProviderOptions),
   http: Schema.optional(HttpOptions),
-  responseFormat: Schema.optional(ResponseFormat),
   cache: Schema.optional(CachePolicy),
   metadata: Schema.optional(Schema.Record(Schema.String, Schema.Unknown)),
 }) {}
@@ -296,7 +288,6 @@ export namespace LLMRequest {
     generation: request.generation,
     providerOptions: request.providerOptions,
     http: request.http,
-    responseFormat: request.responseFormat,
     cache: request.cache,
     metadata: request.metadata,
   })
diff --git a/packages/core/src/aisdk.ts b/packages/core/src/aisdk.ts
index 6d749b8526f..33a4d670af3 100644
--- a/packages/core/src/aisdk.ts
+++ b/packages/core/src/aisdk.ts
@@ -422,7 +422,6 @@ function callOptions(request: LLMRequest): LanguageModelV3CallOptions {
     presencePenalty: request.generation?.presencePenalty,
     frequencyPenalty: request.generation?.frequencyPenalty,
     seed: request.generation?.seed,
-    responseFormat: responseFormat(request),
     tools: request.tools.map(tool),
     toolChoice: toolChoice(request.toolChoice),
     headers: request.http?.headers,
@@ -527,12 +526,6 @@ function toolChoice(input: LLMRequest["toolChoice"]): LanguageModelV3ToolChoice
   return { type: input.type }
 }
 
-function responseFormat(request: LLMRequest): LanguageModelV3CallOptions["responseFormat"] {
-  if (request.responseFormat?.type === "json")
-    return { type: "json", schema: request.responseFormat.schema as JSONSchema7 }
-  if (request.responseFormat) return { type: "text" }
-}
-
 function providerOptions(input: LLMRequest["providerOptions"]): SharedV3ProviderOptions | undefined {
   if (!input) return undefined
   return Object.fromEntries(Object.entries(input).map(([key, value]) => [key, jsonObject(value)]))