Give an agent a tool — fetch a URL

You'll take an agent and give it a single Fetch tool pointed at an HTTP API, so the model can pull live data into a conversation instead of answering from its training alone.

What you need

• A provider and a model that supports tool calls.
• One HTTP endpoint you want to reach, as a URL — public, or one you hold an API key for.
• The API key, if the endpoint needs one (it goes in your device keystore, not in the tool's configuration).

Steps

1. Open the agent you want to extend — or build a simple one first (see Build a simple agent) — and expand its Tools section. Add a Fetch tool.

2. Give the endpoint a name and a one-line description. The model reads the description to decide when to call the tool, and the name becomes part of the tool it sees.

3. Write the URL as a template. Plain text is literal; wrap the parts the model should fill as {variable} — for example https://api.example.com/search?q={query}. {query} is URL-encoded for you; use {+path} when a value must be inserted without encoding, and {?tags*} to expand a list into query parameters.

4. If the endpoint needs a key, put it in the API Key field and reference it in the URL or a header as {apiKey}. The key is stored in your device's keystore and substituted only at call time — it never appears in the tool's saved configuration.

5. Optionally refine the request: choose the HTTP Method and, for POST/PUT/PATCH/DELETE, a Body; add Headers; declare each Variable's type (Text, Integer, Decimal, Boolean), whether it's an array, whether it's required, and a default; and set Retry behaviour for endpoints that rate-limit (429/503 with backoff).

6. Optionally turn on Error handling so a failed response (by default any 4xx/5xx) is flagged as an error rather than passed off as a normal answer: the output filters are skipped and the raw error body comes back, optionally prefixed with the HTTP status. If a raw error page isn't useful to the model, fill in an Error message template — a small template rendered over the error body to produce a clean failure line. {{status}}, {{reason}}, and {{body}} are always available, and a JSON error body exposes its own fields too, so Request failed ({{status}}): {{message}} turns a 429 with {"message": "quota exceeded"} into Request failed (429): quota exceeded.

7. Save the agent and start a conversation. Ask something that needs the endpoint: the model calls the Fetch tool, the response comes back, and the agent answers from it.

Make it yours

• Search the web by pointing a Fetch tool at a search API's endpoint — there is no separate search tool; a fetch tool is how search works.
• Trim noisy responses with a Template output filter, so the model sees only the fields it needs instead of a whole JSON payload.
• Let a model do the trimming with a Model output filter when the response has no fields to pick — a whole HTML page, say. It asks one question about the body and passes the answer on; point it at a small local model and the agent never sees the page at all.
• Add several Fetch tools to one agent — one per endpoint — to hand it a small toolbox of APIs.