Use KV API

Last updated Oct 13, 2025 Interact with persistent storage to retrieve or store information enables for powerful use cases.

In this example we show how embedded function calling can interact with other resources on the Cloudflare Developer Platform with a few lines of code.

Pre-Requisites

For this example to work, you need to provision a KV namespace first. To do so, follow the KV - Get started guide.

Importantly, your Wrangler file must be updated to include the KV binding definition to your respective namespace.

Worker code

Embedded function calling example with KV APIts

import { runWithTools } from "@cloudflare/ai-utils";

type Env = {
    AI: Ai;
    KV: KVNamespace;
};

export default {
    async fetch(request, env, ctx) {
        // Define function
        const updateKvValue = async ({
            key,
            value,
        }: {
            key: string;
            value: string;
        }) => {
            const response = await env.KV.put(key, value);
            return `Successfully updated key-value pair in database: ${response}`;
        };

        // Run AI inference with function calling
        const response = await runWithTools(
            env.AI,
            "@hf/nousresearch/hermes-2-pro-mistral-7b",
            {
                messages: [
                    { role: "system", content: "Put user given values in KV" },
                    { role: "user", content: "Set the value of banana to yellow." },
                ],
                tools: [
                    {
                        name: "KV update",
                        description: "Update a key-value pair in the database",
                        parameters: {
                            type: "object",
                            properties: {
                                key: {
                                    type: "string",
                                    description: "The key to update",
                                },
                                value: {
                                    type: "string",
                                    description: "The value to update",
                                },
                            },
                            required: ["key", "value"],
                        },
                        function: updateKvValue,
                    },
                ],
            },
        );
        return new Response(JSON.stringify(response));
    },
} satisfies ExportedHandler<Env>;

Verify results

To verify the results, run the following command

npx wrangler kv key get banana --binding KV --local

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description: Generate Workers AI function calling tools from an OpenAPI specification using the ai-utils package. title: Tools based on OpenAPI Spec image: https://developers.cloudflare.com/workers-ai/features/function-calling/embedded/examples/openapi/og.png?v=d57cb6344a7eb170

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