URL Shortener (guide)#

This skill is instructions-only. It does not run any code on the device. When the user asks to shorten a URL, the agent should use the existing http_fetch tool to call one of the public shortener APIs below and then return the response body as the short URL.

Preferred backend: da.gd#

GET https://da.gd/s?url=<URL-encoded original URL>

Exactly one call. Response body is the short URL as plain text (no JSON).

Agent procedure#

1. Extract the original URL from the user's message.

   • It must start with http:// or https://. If not, ask the user to provide one.

2. URL-encode the original URL (apply encodeURIComponent to it).

3. Call http_fetch with these parameters:

   • url: https://da.gd/s?url=<encoded original>
   • method: GET

4. Take the raw response body, strip surrounding whitespace, and verify it starts with https://da.gd/. If so, return that as the short URL.

5. If the body doesn't match, or the status is not 2xx, fall back to one of the alternate backends below.

Example#

Original:

text

https://github.com/anthropics/claude-code/tree/main/docs/very/long/path

Encoded:

text

https%3A%2F%2Fgithub.com%2Fanthropics%2Fclaude-code%2Ftree%2Fmain%2Fdocs%2Fvery%2Flong%2Fpath

Fetch:

text

http_fetch({ url: "https://da.gd/s?url=https%3A%2F%2Fgithub.com%2Fanthropics%2Fclaude-code%2Ftree%2Fmain%2Fdocs%2Fvery%2Flong%2Fpath", method: "GET" })

Expected response body: https://da.gd/XXXXXX

Fallback 1: cleanuri.com#

POST https://cleanuri.com/api/v1/shorten

• method: POST
• content_type: application/x-www-form-urlencoded
• body: url=<URL-encoded original URL>

Response is JSON: {"result_url": "https://cleanuri.com/XXXXXX"}. Parse and return result_url.

Fallback 2: tinyurl.com (unreliable)#

GET https://tinyurl.com/api-create.php?url=<URL-encoded original URL>

Response body is plain text like https://tinyurl.com/XXXXXX. Some clients get bot-detected and receive a "deprecated preview" placeholder — if the response body lies outside the https://tinyurl.com/ domain or redirects to tinyurl.com/preview/deprecated, treat it as a failure and move on.

Notes for the agent#

• Always verify the final short URL's domain matches the backend's own domain before returning it.
• If all three backends fail, tell the user honestly — do not fabricate a short URL.
• The user cares about reaching the original URL through the short link. Do not silently substitute a different destination.