refactor(ai): remove maxSteps parameter from prepareStep function and update related calls

Author: yaonyan

packages/ai/core/generate-text/generate-text.ts

@@ -331,7 +331,6 @@ A function that attempts to repair a tool call that failed to parse.
         const prepareStepResult = await prepareStep?.({
           model,
           steps,
-          maxSteps,
           stepNumber: stepCount,
           messages: promptMessages,
         });

packages/ai/core/generate-text/prepare-step.ts

@@ -21,7 +21,6 @@ export type PrepareStepFunction<
 > = (options: {
   steps: Array<StepResult<NoInfer<TOOLS>>>;
   stepNumber: number;
-  maxSteps: number;
   model: LanguageModel;
   messages: Array<LanguageModelV1Message>;
 }) => PromiseLike<PrepareStepResult<TOOLS>> | PrepareStepResult<TOOLS>;

packages/ai/core/generate-text/stream-text.test.ts

@@ -2982,8 +2982,21 @@ describe('streamText', () => {
               case 1: {
                 expect(mode).toStrictEqual({
                   type: 'regular',
-                  toolChoice: { type: 'auto' },
-                  tools: [],
+                  toolChoice: { type: 'tool', toolName: 'tool1' },
+                  tools: [
+                    {
+                      type: 'function',
+                      name: 'tool1',
+                      description: undefined,
+                      parameters: {
+                        $schema: 'http://json-schema.org/draft-07/schema#',
+                        additionalProperties: false,
+                        properties: { value: { type: 'string' } },
+                        required: ['value'],
+                        type: 'object',
+                      },
+                    },
+                  ],
                 });
 
                 expect(prompt).toStrictEqual([

packages/ai/core/generate-text/stream-text.ts

@@ -995,8 +995,7 @@ class DefaultStreamTextResult<TOOLS extends ToolSet, OUTPUT, PARTIAL_OUTPUT>
           const prepareStepResult = await prepareStep?.({
             model,
             steps: recordedSteps,
-            stepNumber: currentStep,
-            maxSteps,
+            stepNumber: recordedSteps.length,
             messages: stepInputMessages
           });