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# SwmlTransferSkill

> Transfer calls between agents/endpoints based on pattern matching.

[add-skill]: /docs/server-sdks/reference/typescript/agents/agent-base/add-skill

Transfer calls between agents or endpoints using SWML transfer actions. The
skill accepts either a **Python-style `transfers`** config (regex pattern →
per-entry config) or a **TypeScript-style `patterns`** array of named
destinations. At least one of the two shapes is required — `setup()` fails
closed otherwise.

**Class:** `SwmlTransferSkill`

**Tools:** `transfer_call` always; `list_transfer_destinations` additionally
registered when at least one entry is supplied in `patterns`.

**Env vars:** None

**Multi-instance:** yes — set a distinct `tool_name` per instance.

**`transfers`** `Record<string, TransferConfig>`

Python-style map of transfer configs keyed by regex pattern (or name). Each
entry includes either `url` or `address` (not both), plus optional
`message`, `return_message`, `post_process`, `final`, and `from_addr`.

Either `transfers` or `patterns` must be provided; both may be combined.
`setup()` fails closed when neither is configured.

---

**`patterns`** `TransferPattern[]`

TypeScript-style array of named transfer patterns. Each object has:

* `name` (string, required) — friendly name for the destination.
* `destination` (string, required) — SIP URI, phone number, or agent URL.
* `description` (string) — optional human-readable description.
* `message` / `returnMessage` / `postProcess` / `final` / `fromAddr` —
  optional per-pattern overrides.

---

**`allow_arbitrary`** `boolean`

Whether to allow transfers to arbitrary destinations not listed in
`patterns` / `transfers`. When unset, defaults depend on whether any
patterns are configured.

---

**`tool_name`** `string` — default: transfer\_call

Name of the transfer tool exposed to the AI.

---

**`description`** `string` — default: Transfer call based on pattern matching

Description for the transfer tool shown to the AI.

---

**`parameter_name`** `string` — default: transfer\_type

Name of the parameter that accepts the transfer type.

---

**`parameter_description`** `string` — default: The type of transfer to perform

Description for the transfer-type parameter.

---

**`default_message`** `string` — default: Please specify a valid transfer type.

Message spoken when no pattern matches.

---

**`default_post_process`** `boolean` — default: false

Whether to post-process the default message with the AI.

---

**`required_fields`** `Record<string, string>` — default: \{}

Map of additional fields (name → description) the agent must collect before
a transfer.

---

> **Note**
>
> Regex patterns in `transfers` are matched **case-sensitively**. Use character
> classes or flags in the source pattern when case-insensitive matching is
> needed.

## Example — TypeScript patterns

```typescript {6-20}
import { AgentBase, SwmlTransferSkill } from '@signalwire/sdk';

const agent = new AgentBase({ name: 'assistant', route: '/assistant' });
agent.setPromptText('You are a helpful assistant.');

await agent.addSkill(new SwmlTransferSkill({
  patterns: [
    {
      name: 'sales',
      destination: 'https://your-server.com/sales-agent',
      description: 'Sales team',
    },
    {
      name: 'support',
      destination: '+15551234567',
      description: 'Technical support line',
    },
  ],
  default_message: 'Please specify sales or support.',
}));

agent.run();
```

## Example — Python-style transfers

```typescript {6-14}
import { AgentBase, SwmlTransferSkill } from '@signalwire/sdk';

const agent = new AgentBase({ name: 'assistant', route: '/assistant' });
agent.setPromptText('You are a helpful assistant.');

await agent.addSkill(new SwmlTransferSkill({
  transfers: {
    '^sales$':   { address: 'sip:sales@signalwire.com' },
    '^support$': { url: 'https://your-server.com/support-agent' },
  },
}));

agent.run();
```

> Transfer calls between agents/endpoints based on pattern matching.