# Links

Declare static destinations on the agent that may hand them out:

```yaml
agent:
  instructions: …
  links:
    help: https://acme.com/help
    product:
      url: https://acme.com/products/{category}
      when: The visitor wants to browse a product category.
      values:
        category: [picking, packing, sorting]
```

A value can be a URL string or a mapping with `url`, optional `when`, and
`values` for every placeholder. URLs must be absolute HTTP or HTTPS URLs.
Placeholder values use letters, digits, `.`, `_`, `~`, or `-`.

Vatio expands every combination at deploy time, with a limit of 100 URLs.
Use a tool for dynamic destinations or larger catalogs. Links returned by a
tool are allowed for the rest of that conversation.

A URL written straight into `instructions` is shareable too, so a one-off
mention needs no entry here. `links` remains the better place for a
destination the agent should actually offer: it carries a `when` that tells
the agent when to reach for it, and it expands placeholders.

Which URLs a reply may carry at all is enforced by the
[safeguards](https://vatio.ai/docs/safeguards).