Built In Agent Helper Utilities

BuiltInAgent helper utilities — exported from @copilotkit/runtime/v2.

convertInputToTanStackAI

import { convertInputToTanStackAI } from "@copilotkit/runtime/v2";

// signature (simplified):
// convertInputToTanStackAI(input: RunAgentInput): {
//   messages: TanStackAIMessage[];
//   systemPrompts: string[];
// }

Converts the AG-UI RunAgentInput into TanStack AI's chat() inputs. System messages in the input are collected into the systemPrompts array (not the messages array). Unshift your own system prompt onto systemPrompts before calling chat():

const { messages, systemPrompts } = convertInputToTanStackAI(input);
systemPrompts.unshift("You are a helpful assistant.");
return chat({ adapter, messages, systemPrompts, abortController });

Source: packages/runtime/src/agent/converters/tanstack.ts:156.

convertMessagesToVercelAISDKMessages

import { convertMessagesToVercelAISDKMessages } from "@copilotkit/runtime/v2";

// signature:
// convertMessagesToVercelAISDKMessages(
//   messages: Message[],
//   options?: { forwardSystemMessages?: boolean; forwardDeveloperMessages?: boolean }
// ): ModelMessage[]

Converts AG-UI Message[] to the Vercel AI SDK's ModelMessage[]. Handles multimodal content (text, image, audio/video/document, and legacy binary). By default drops role: "system" and role: "developer" messages — set the options to opt in.

const messages = convertMessagesToVercelAISDKMessages(input.messages, {
  forwardSystemMessages: true,
});

Source: packages/runtime/src/agent/index.ts:435.

convertToolsToVercelAITools

import { convertToolsToVercelAITools } from "@copilotkit/runtime/v2";

// signature:
// convertToolsToVercelAITools(tools: RunAgentInput["tools"]): ToolSet

Converts AG-UI input.tools (tools registered on the frontend — their parameters are plain JSON Schema) into the AI SDK's ToolSet. Throws Invalid JSON schema for tool ${name} when a tool's parameters aren't a JSON schema object. The resulting tools have no execute — the AI SDK emits tool-call events and the frontend handles them.

const tools = convertToolsToVercelAITools(input.tools);
return streamText({ model, messages, tools, abortSignal });

Source: packages/runtime/src/agent/index.ts:599.

convertToolDefinitionsToVercelAITools

import { convertToolDefinitionsToVercelAITools } from "@copilotkit/runtime/v2";

// signature:
// convertToolDefinitionsToVercelAITools(tools: ToolDefinition[]): ToolSet

Converts server-side ToolDefinition[] (Standard Schema V1 parameters + execute function) into an AI SDK ToolSet. Zod schemas pass through directly; non-Zod Standard Schema V1 parameters (Valibot, ArkType, ...) are converted to JSON Schema via schemaToJsonSchema and wrapped with jsonSchema() from ai.

import { defineTool } from "@copilotkit/runtime/v2";
import { z } from "zod";

const searchTool = defineTool({
  name: "search",
  description: "Search the web.",
  parameters: z.object({ query: z.string() }),
  execute: async ({ query }) => ({ results: [] }),
});

const tools = convertToolDefinitionsToVercelAITools([searchTool]);
return streamText({ model, messages, tools, abortSignal });

Source: packages/runtime/src/agent/index.ts:633.

resolveModel

import { resolveModel } from "@copilotkit/runtime/v2";

// signature:
// resolveModel(spec: ModelSpecifier, apiKey?: string): LanguageModel

Resolves a "provider/model" (or "provider:model") string to a LanguageModel. If spec is already a LanguageModel, it's returned as-is. Throws Invalid model string "..." when the provider separator is missing.

Supported providers: openai, anthropic, google/gemini/google-gemini, vertex. Unknown providers throw Unknown provider "..." in "...". Supported: openai, anthropic, google (gemini).

const model = resolveModel("openai/gpt-4o", process.env.OPENAI_API_KEY);

Source: packages/runtime/src/agent/index.ts:176-249.