microfn

MicroFn Skills

Repo: microfnhq/skills

Agent kills for working with MicroFn - a cloud platform that turns JavaScript snippets into persistent, callable functions for your AI agent.

This is using the microfn CLI under the hood

What is MicroFn?

MicroFn is a programmable toolbox for AI agents. Instead of being limited to built-in tools, you can write custom JavaScript functions, deploy them to isolated sandboxes in the cloud, and have your AI agent execute them on demand.

Think of it like this: Your AI agent can now fetch weather data, send Discord messages, query databases, store state between conversations, access secrets securely, and call any API - all by deploying tiny JavaScript functions that live in the cloud and can be invoked anytime.

The magic: Your AI agent can write and deploy its own tools on the fly. Need a capability that doesn't exist yet? The agent can create a function, deploy it to MicroFn, and immediately start using it. It's like giving your AI the ability to extend itself with custom tools as needed.

Installation

npx skills add microfnhq/skills

To list all available skills:

npx skills add microfnhq/skills --list

Available Skills

microfn

This skill teaches Claude how to use the MicroFn CLI (microfn or mfn) to deploy, update, inspect, and execute sandboxed JavaScript functions. Functions can power your applications and be exposed as MCP tools that your AI agent can call directly.

Why is this powerful?

Your AI agent can now have custom capabilities beyond its built-in tools. Need to check the weather? Deploy a function. Want to send a Discord notification? Deploy a function. Need to remember something between conversations? Use KV storage. Want to call a private API? Store the API key as a secret and deploy a function.

Self-extending AI agents: The most powerful feature is that your AI agent can create new tools for itself. During a conversation, if your agent needs a capability that doesn't exist, it can:

1. Write a JavaScript function for that capability
2. Deploy it to MicroFn with microfn create
3. Immediately execute it with microfn execute
4. Optionally expose it as an MCP tool for reuse

This means your agent gets smarter and more capable over time by building its own toolbox.

Real-world examples:

🌤️ Weather service with caching

import kv from "@microfn/kv";

export async function main(input) {
  const cached = await kv.get(`weather:${input.city}`);
  if (cached) return cached;

  const response = await fetch(
    `https://api.openweathermap.org/data/2.5/weather?q=${input.city}`,
  );
  const weather = await response.json();

  await kv.set(`weather:${input.city}`, weather, { ttl: 3600 });
  return weather;
}

Deploy once, call anytime: microfn execute myuser/weather '{"city":"Tokyo"}'

💬 Discord/Slack notifications

import secret from "@microfn/secret";

export async function main(input) {
  const webhook = await secret.get("DISCORD_WEBHOOK");

  await fetch(webhook, {
    method: "POST",
    headers: { "Content-Type": "application/json" },
    body: JSON.stringify({
      content: input.message,
      username: "AI Agent Bot",
    }),
  });

  return { sent: true, timestamp: new Date().toISOString() };
}

Your AI can now send notifications to your team!

📊 Stateful counter with analytics

import kv from "@microfn/kv";

export async function main(input) {
  const count = (await kv.get("total_requests")) || 0;
  const newCount = count + 1;

  await kv.set("total_requests", newCount);
  await kv.set(`request:${newCount}`, {
    timestamp: Date.now(),
    data: input,
  });

  return { requestNumber: newCount, totalRequests: newCount };
}

Track state across conversations and function calls.

🔐 Authenticated API calls

import secret from "@microfn/secret";

export async function main(input) {
  const apiKey = await secret.get("GITHUB_TOKEN");

  const response = await fetch(
    `https://api.github.com/repos/${input.repo}/issues`,
    {
      headers: {
        Authorization: `Bearer ${apiKey}`,
        Accept: "application/vnd.github.v3+json",
      },
    },
  );

  return await response.json();
}

Securely call private APIs without exposing credentials.

More possibilities:

• Process and transform data in custom ways
• Validate inputs with your own business logic
• Integrate with any REST API (Stripe, Twilio, SendGrid, etc.)
• Build stateful workflows that remember context
• Create custom tools specifically for your AI agent's needs
• Schedule recurring tasks or webhooks

Invoke: /microfn

Resources

• MicroFn Platform