Skills — Single-Purpose Tools

Skills are atomic units of functionality. Each skill does exactly one thing: send an email, generate a PDF, create a JIRA ticket, enrich a lead record. They sit between raw Functions (general backend logic) and MCP Servers (multi-tool platform connectors) in the Aerostack hierarchy.

Note

Skills are deployed as Cloudflare Workers and installed into Workspaces. Once installed, they are available to any bot, LLM client, or agent connected to that workspace — no additional configuration required.

How Skills Fit In

You deploy a skill once. You install it into one or more workspaces. Every consumer of that workspace — bots, Claude Desktop, Cursor, custom agents — can call it immediately.

Skills vs Functions vs MCP Servers

	Functions	Skills	MCP Servers
Purpose	General backend logic	One tool, one job	Multi-tool platform connector
Tools exposed	0 (raw HTTP)	1	Many (5-50+)
Example	Order processing pipeline	send-email	Stripe MCP (20+ tools)
Deploy command	aerostack deploy function	aerostack deploy skill	aerostack deploy mcp
Workspace role	Added as a tool	Added as a tool	Added as a server
Complexity	You define everything	Structured single tool	Full protocol implementation
Best for	Custom APIs, pipelines	Reusable atomic actions	Platform integrations

When to use each:

• Function — you need a custom API, a multi-endpoint backend, or a pipeline that does not fit the single-tool model.
• Skill — you have one well-defined action that should be callable by any AI agent in the workspace.
• MCP Server — you are wrapping an external platform (Stripe, GitHub, Slack) and need to expose many related tools.

Use Cases

Single-purpose automation

Send a Slack alert, create a JIRA ticket, generate an invoice PDF, post to a Discord channel. One skill per action, composable across workspaces.

Workflow building block

Skills compose into multi-step bot workflows. A bot workflow might call validate-address, then calculate-shipping, then send-confirmation-email — each a separate skill.

Team utility toolkit

Build private skills for your organization: internal lookup tools, formatting utilities, data validation helpers. Install them into your team workspace and every team member’s AI tools can use them.

Bot capability extension

Need your bot to send emails? Install the send-email skill into the bot’s workspace. The bot can now call it — no code changes to the bot itself.

Cron-triggered actions

Skills can run on a schedule. A daily-digest skill aggregates data from your database and sends a summary. A weekly-report skill generates analytics and posts them to Slack.

Quick Example

A skill that sends a Slack notification:

src/index.ts

interface Env {
  SLACK_WEBHOOK_URL: string
}

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const { channel, message } = await request.json<{
      channel: string
      message: string
    }>()

    if (!channel || !message) {
      return Response.json(
        { error: 'channel and message are required' },
        { status: 400 }
      )
    }

    const response = await fetch(env.SLACK_WEBHOOK_URL, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify({ channel, text: message })
    })

    if (!response.ok) {
      return Response.json(
        { error: 'Failed to send Slack message' },
        { status: 502 }
      )
    }

    return Response.json({ success: true, channel })
  }
}

aerostack.json

{
  "name": "slack-notify",
  "type": "skill",
  "description": "Send a notification to a Slack channel",
  "tool": {
    "name": "send_slack_notification",
    "description": "Sends a message to a specified Slack channel",
    "input_schema": {
      "type": "object",
      "properties": {
        "channel": {
          "type": "string",
          "description": "The Slack channel to send to (e.g. #alerts)"
        },
        "message": {
          "type": "string",
          "description": "The message text to send"
        }
      },
      "required": ["channel", "message"]
    }
  }
}

Deploy it, install it into a workspace, and any bot or LLM client connected to that workspace can send Slack notifications.

Platform Bindings

Skills have full access to the same edge runtime bindings as Functions:

Binding	Access	Example
Database	env.DB	Store skill state, query data
Cache	env.CACHE	Cache expensive computations
Queue	env.QUEUE	Offload async work
AI	env.AI	Run LLM completions, embeddings
Vector Search	env.VECTORIZE	Semantic search
Storage	env.STORAGE	Store files (PDFs, images)

Next Steps

• Create a skill — step-by-step guide with three complete examples
• Deploy and test — CLI deployment, dashboard setup, and local testing
• Publish to Hub — share your skill with the Aerostack community