ModelRouter

Defined in: src/models/routing/router.ts:117

Routes each agent invocation among an immutable set of candidate models.

The default FallbackStrategy prefers the candidate with the fewest recorded failures and breaks ties by declaration order. maxSwitches bounds successful candidate changes per invocation.

Example

const router = new ModelRouter([
  new RoutingCandidate({ model: primary, name: 'primary' }),
  new RoutingCandidate({ model: fallback, name: 'fallback' }),
])
const agent = new Agent({ model: router })

Implements

• Plugin

Constructors

Constructor

new ModelRouter(models, options?): ModelRouter;

Defined in: src/models/routing/router.ts:133

Create a model router.

Parameters

Parameter	Type	Description
models	readonly CandidateInput[]	Candidate models, nested routers, or candidate wrappers
options	ModelRouterOptions	Routing strategy and switch cap

Returns

ModelRouter

Throws

TypeError if models or the strategy are invalid

Throws

Error if candidates are empty, duplicated, named alike, stateful, or maxSwitches is not a non-negative integer

Properties

name

readonly name: "strands:model-router" = 'strands:model-router';

Defined in: src/models/routing/router.ts:118

A stable string identifier for the plugin. Used for logging, duplicate detection, and plugin management.

For strands-vended plugins, names should be prefixed with strands:.

Implementation of

Plugin.name

Accessors

candidates

Get Signature

get candidates(): readonly RoutingCandidate[];

Defined in: src/models/routing/router.ts:152

Normalized candidates in declaration order.

Returns

readonly RoutingCandidate[]

---

defaultModel

Get Signature

get defaultModel(): Model;

Defined in: src/models/routing/router.ts:157

First declared candidate resolved without consulting a strategy.

Returns

Model

Methods

initAgent()

initAgent(agent): void;

Defined in: src/models/routing/router.ts:179

Register routing middleware and lifecycle hooks.

Parameters

Parameter	Type	Description
agent	LocalAgent	Agent using this router as its model

Returns

void

Throws

Error if attached as an ordinary plugin rather than as the model

Implementation of

Plugin.initAgent