Workers AI Function Calling types

[Cherry]

I copied the "traditional" example at https://developers.cloudflare.com/workers-ai/function-calling/ into a worker like this:

export default {
	async fetch(request, env, ctx): Promise<Response> {
		const response = await env.AI.run(
			"@hf/nousresearch/hermes-2-pro-mistral-7b", {
				messages: [{
					role: "user",
					content: "Who is Cloudflare on github?"
				}],
				tools: [{
					name: "getGithubUser",
					description: "Provides publicly available information about someone with a GitHub account.",
					parameters: {
						type: "object",
						properties: {
							username: {
								type: "string",
								description: "The handle for the GitHub user account.",
							},
						},
						required: ["username"],
					},
				}, ],
			},
		);

		const selected_tool = response.tool_calls[0];
		let res;

		if (selected_tool.name == "getGithubUser") {
			try {
				const username = selected_tool.arguments.username;
				const url = `https://api.github.com/users/${username}`;
				res = await fetch(url, {
					headers: {
						// Github API requires a User-Agent header
						"User-Agent": "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/112.0.0.0 Safari/537.36",
					},
				}).then((res) => res.json());
			} catch (error) {
				return error;
			}
		}

		const finalResponse = await env.AI.run(
			"@hf/nousresearch/hermes-2-pro-mistral-7b", {
				messages: [{
						role: "user",
						content: "Who is Cloudflare on github?",
					},
					{
						role: "assistant",
						content: "",
						tool_call: selected_tool.name,
					},
					{
						role: "tool",
						name: selected_tool.name,
						content: JSON.stringify(res),
					},
				],
				tools: [{
					name: "getGithubUser",
					description: "Provides publicly available information about someone with a GitHub account.",
					parameters: {
						type: "object",
						properties: {
							username: {
								type: "string",
								description: "The handle for the GitHub user account.",
							},
						},
						required: ["username"],
					},
				}, ],
			},
		);
		return new Response(JSON.stringify(finalResponse));
	},
} satisfies ExportedHandler<Env>;

where Env is:

interface Env {
	AI: Ai;
}

This resulted in the following TypeScript errors in VSCode and when I ran npx tsc --noEmit:

src/index.ts:4:4 - error TS2769: No overload matches this call.
  The last overload gave the following error.
    Argument of type '"@hf/nousresearch/hermes-2-pro-mistral-7b"' is not assignable to parameter of type 'BaseAiImageToTextModels'.

4    "@hf/nousresearch/hermes-2-pro-mistral-7b", {
     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  node_modules/@cloudflare/workers-types/experimental/index.d.ts:3718:3
    3718   run(
           ~~~
    The last overload is declared here.

src/index.ts:26:34 - error TS2339: Property 'tool_calls' does not exist on type '(((AiTextClassificationOutput & Uint8Array & (AiTextEmbeddingsOutput & AiSpeechRecognitionOutput & AiTextGenerationOutput)) & AiTranslationOutput) & AiSummarizationOutput) & AiImageToTextOutput'.
  Property 'tool_calls' does not exist on type 'AiTextClassificationOutput & Uint8Array & AiTextEmbeddingsOutput & AiSpeechRecognitionOutput & ReadableStream<...> & AiTranslationOutput & AiSummarizationOutput & AiImageToTextOutput'.

26   const selected_tool = response.tool_calls[0];
                                    ~~~~~~~~~~

src/index.ts:40:5 - error TS2322: Type 'unknown' is not assignable to type 'Response'.

40     return error;
       ~~~~~~

src/index.ts:45:4 - error TS2769: No overload matches this call.
  The last overload gave the following error.
    Argument of type '"@hf/nousresearch/hermes-2-pro-mistral-7b"' is not assignable to parameter of type 'BaseAiImageToTextModels'.

45    "@hf/nousresearch/hermes-2-pro-mistral-7b", {
      ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

  node_modules/@cloudflare/workers-types/experimental/index.d.ts:3718:3
    3718   run(
           ~~~
    The last overload is declared here.


Found 4 errors in the same file, starting at: src/index.ts:4

I suspect this is somewhat related to the function overloading DX issues as reported at #2181.

[petebacondarwin]

Thanks for the report. It looks like #2181 is being addressed. So let's circle back here after that is done and see if this is fixed.