url-shortener-mcp

A URL shortener exposed as an MCP server. Built with Express, Prisma, TypeScript, and SQLite.

Shorten URLs, set expiry times, tag them with a purpose note, and manage your links directly from any MCP-compatible LLM client.

This server is designed to be deployed remotely. Short URLs are only useful if they resolve publicly, and MCP clients connect over HTTP — so the server should run on a machine with a public hostname (e.g. a VPS, cloud VM, or PaaS). Set HOSTNAME to your public domain and HTTPS=true in production. Running it on localhost is fine for development, but short links won't be shareable outside your machine.

Table of Contents

• Quick Start (npx)

• Getting Started (from source)

• Docker

• MCP Configuration

• MCP Capabilities

  • Tools

  • Resources

  • Prompts

  • Sampling

• AI Agent Rules

• REST API

• Environment Variables

• Example Use Cases

• Development

Quick Start (npx)

The fastest way to get running — no cloning required:

npx url-shortener-mcp --port 3000 --hostname your-domain.com --https true

On first run the server will:

1. Create a fresh SQLite database and apply all migrations automatically

2. Generate an API key and print it once — save it, it will not be shown again

3. Start listening

All environment variables can be passed as CLI flags:

npx url-shortener-mcp \
  --port 3000 \
  --database-url file:/data/urls.db \
  --hostname your-domain.com \
  --https true \
  --enable-api true \
  --enable-mcp true

Flags take precedence over values set in a .env file.

Creating a user

To create a user without starting the server, pass --create-user:

npx url-shortener-mcp --create-user

This prints a user ID and API key, then exits. Store the key securely — it will not be shown again.

Getting Started (from source)

1. Install dependencies

pnpm install

2. Set up environment

pnpm init-env

This copies .env.example to .env. Edit .env to configure your hostname, port, and other settings.

3. Run database migrations

pnpm db:migrate

4. Create a user

pnpm user:create

This outputs a user ID and API key. Store the key securely — it will not be shown again.

User created successfully.

  ID:  clxyz...
  Key: a1b2c3d4...

Store this key securely — it will not be shown again.

5. Start the server

Development (with hot reload):

pnpm dev

Production:

pnpm build && pnpm start

The server runs on http://localhost:3000 by default.

Docker

Setup

pnpm init-env

Edit .env to configure your hostname, port, and other settings.

Development

Hot reload via nodemon + ts-node:

docker compose up

Production

Compiles TypeScript and runs the built output:

docker compose -f docker-compose.prod.yaml up

The database is persisted in a named Docker volume (db_data).

MCP Configuration

Add this server to your MCP client (e.g. Claude Desktop, Cursor):

{
  "mcpServers": {
    "url-shortener": {
      "url": "https://your-domain.com/mcp",
      "headers": {
        "Authorization": "Bearer <your-api-key>"
      }
    }
  }
}

Replace https://your-domain.com with the public URL of your deployed server.

MCP Capabilities

Tools

The tag field

shorten_url and bulk_shorten_urls accept an optional tag — a short, agent-written note describing a URL's purpose (e.g. "stripe webhook docs", "PR #99", "staging deploy"). Tags are stored alongside the URL and are searchable via search_urls. Setting a tag at creation time means you can retrieve any URL later by purpose without keeping the full URL in context.

The estimatedTokensSaved field

Each URL record includes estimatedTokensSaved — an estimate of how many tokens are saved per substitution when using the slug instead of the full URL (computed using a ~4 chars/token heuristic). This is a per-use delta, not a cumulative total. Token savings only materialise when the slug is reused across multiple turns; single-use URLs will cost more context overall than pasting the original URL inline. get_stats returns the sum across all active URLs.

Resources

Prompts

Sampling

When a client supports the MCP sampling capability and either slug or tag is missing from a shorten_url call, the server asks the connected LLM to suggest both in a single round-trip — returning a JSON object with a short, memorable slug and a brief purpose tag. If sampling is not supported or fails, a random slug is generated and tag is left unset.

AI Agent Rules

Add the following rule to your CLAUDE.md, system prompt, or any file your AI client loads as instructions. It tells the agent to automatically load URLs into the shortener during research so they can be retrieved later without bloating the context window.

## URL Shortener

This MCP server is available for shortening and tracking URLs.

When you encounter or are given a URL during research, browsing, or tool use:
1. Shorten it immediately using the `shorten_url` tool.
2. Always set a `tag` — a short phrase describing the URL's purpose
   (e.g. "auth API reference", "PR #42", "deployment guide").
3. Use the returned short URL in all subsequent messages and tool calls
   instead of the full URL.

When you need to refer back to a URL:
- Use `search_urls` with a partial `tag` or `longUrl` fragment to find it.
- Do not keep full URLs in your context when a slug exists for them.

Tag examples:
  "stripe webhook docs"   — for https://stripe.com/docs/webhooks
  "main repo"             — for the project's GitHub URL
  "PR #99"                — for a specific pull request
  "staging deploy"        — for a deployment URL you need to revisit

This rule is particularly effective in long research sessions where many URLs appear — tagging at creation time means you can retrieve any link later with a natural-language search rather than scrolling back through the conversation.

REST API

The server exposes a REST API under /urls using the same Bearer token auth. Short URLs resolve via public redirects at /:slug.

Environment Variables

Example Use Cases

Once configured, you can ask your LLM assistant:

"Shorten https://github.com/anthropics/anthropic-sdk-python/blob/main/README.md with a custom slug anthropic-py that expires in 12 hours, then list all my active URLs."

The assistant will call shorten_url with longUrl, slug, and ttl set appropriately, then call list_urls to show you the results — returning something like http://localhost:3000/anthropic-py.

If no slug or tag is provided and sampling is supported, the assistant will automatically suggest both:

"Shorten https://github.com/anthropics/anthropic-sdk-python/blob/main/README.md"

→ The server asks the LLM to suggest a slug (e.g. anthropic-sdk-py) and a tag (e.g. anthropic python SDK readme), then creates the short URL with both set.

You can retrieve a URL later by the tag you set at creation time:

"Find the URL I saved for the Anthropic SDK docs."

→ The assistant calls search_urls with tag: "anthropic" and returns the matching short URL — no need to keep the full URL in context.

You can also check your overall usage:

"How many URLs have I shortened and what's my total estimated token savings?"

→ The assistant calls get_stats and reports the aggregate count and totalEstimatedTokensSaved across all active URLs.

You can also read your URLs as resources:

"Show me everything at urls://all"

→ The client fetches the urls://all resource and the assistant summarises your active links.

Development

pnpm test           # run tests
pnpm test:coverage  # coverage report
pnpm check          # lint + format
pnpm db:studio      # open Prisma Studio