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Effect V4 Docs

AnthropicClient.ts

AnthropicClient.ts overview

Section titled “AnthropicClient.ts overview”

The AnthropicClient module defines the low-level Effect service for Anthropic’s Messages API. It builds a generated Anthropic HTTP client with authentication headers, API version headers, response decoding, and error mapping, then exposes helpers for regular and streaming message requests.

Since v4.0.0

Exports Grouped by Category

Section titled “Exports Grouped by Category”

constructors

Section titled “constructors”

make

Section titled “make”

Creates an Anthropic client service with the given options.

When to use

Use when you have explicit configuration values and need an Effect that constructs the Anthropic client service, rather than providing it as a Layer.

Details

The client handles API key authentication via the x-api-key header, API versioning via the anthropic-version header, error mapping to the unified AiError type, and request/response transformations via AnthropicConfig. It requires an HttpClient in the context.

See

  • layer for providing the client as a Layer from explicit options
  • layerConfig for providing the client as a Layer with Config-based settings

Signature

declare const make: (options: Options) => Effect.Effect<Service, never, HttpClient.HttpClient>

Source

Since v4.0.0

layers

Section titled “layers”

layer

Section titled “layer”

Creates a layer for the Anthropic client with the given options.

When to use

Use when you already have explicit Options values, such as an API key or custom API URL, and want to provide AnthropicClient as a Layer.

See

  • make for constructing the client service effectfully
  • layerConfig for loading client settings from Config

Signature

declare const layer: (options: Options) => Layer.Layer<AnthropicClient, never, HttpClient.HttpClient>

Source

Since v4.0.0

layerConfig

Section titled “layerConfig”

Creates a layer for the Anthropic client, loading the requisite configuration via Effect’s Config module.

When to use

Use when you want to provide the Anthropic client as a Layer with configuration loaded from Effect’s Config module, such as from environment variables or a secrets provider.

See

  • layer for providing the client from explicit options instead of Config
  • make for constructing the client service effectfully

Signature

declare const layerConfig: (options?: {
  readonly apiKey?: Config.Config<Redacted.Redacted<string> | undefined> | undefined
  readonly apiUrl?: Config.Config<string> | undefined
  readonly apiVersion?: Config.Config<string> | undefined
  readonly transformClient?: ((client: HttpClient.HttpClient) => HttpClient.HttpClient) | undefined
}) => Layer.Layer<AnthropicClient, Config.ConfigError, HttpClient.HttpClient>

Source

Since v4.0.0

models

Section titled “models”

MessageStreamEvent (type alias)

Section titled “MessageStreamEvent (type alias)”

Represents an event received from the Anthropic Messages API during a streaming request.

Details

Events include:

  • message_start: Initial event containing message metadata
  • message_delta: Incremental updates to the message (e.g., stop reason)
  • message_stop: Final event indicating the message is complete
  • content_block_start: Start of a content block
  • content_block_delta: Incremental content updates (text, tool use, etc.)
  • content_block_stop: End of a content block
  • error: Error events with type and message

Signature

type MessageStreamEvent =
  | typeof Generated.BetaMessageStartEvent.Type
  | typeof Generated.BetaMessageDeltaEvent.Type
  | typeof Generated.BetaMessageStopEvent.Type
  | typeof Generated.BetaContentBlockStartEvent.Type
  | typeof Generated.BetaContentBlockDeltaEvent.Type
  | typeof Generated.BetaContentBlockStopEvent.Type
  | typeof Generated.BetaErrorResponse.Type

Source

Since v4.0.0

Service (interface)

Section titled “Service (interface)”

Represents the Anthropic client service with methods for the Messages API, including regular and streaming message creation.

Signature

export interface Service {
  /**
   * The underlying generated Anthropic client that exposes all API endpoints.
   */
  readonly client: Generated.AnthropicClient


  /**
   * Executes a low-level streaming HTTP request and decodes the Server-Sent Events response using the provided schema.
   */
  readonly streamRequest: <S extends Sse.EventCodec>(
    schema: S
  ) => (
    request: HttpClientRequest.HttpClientRequest
  ) => Stream.Stream<S["Type"], HttpClientError.HttpClientError | Schema.SchemaError | Sse.Retry, S["DecodingServices"]>


  /**
   * Creates a message using the Anthropic Messages API and maps all errors to the unified `AiError` type.
   */
  readonly createMessage: (options: {
    readonly payload: typeof Generated.BetaCreateMessageParams.Encoded
    readonly params?: typeof Generated.BetaMessagesPostParams.Encoded | undefined
  }) => Effect.Effect<
    [body: typeof Generated.BetaMessage.Type, response: HttpClientResponse.HttpClientResponse],
    AiError.AiError
  >


  /**
   * Creates a streaming message using the Anthropic Messages API and maps all errors to the unified `AiError` type.
   *
   * **Details**
   *
   * The returned Effect yields the HTTP response and a stream of events as the model generates its response. The stream
   * automatically terminates when a `message_stop` event is received.
   */
  readonly createMessageStream: (options: {
    readonly payload: Omit<typeof Generated.BetaCreateMessageParams.Encoded, "stream">
    readonly params?: typeof Generated.BetaMessagesPostParams.Encoded | undefined
  }) => Effect.Effect<
    [response: HttpClientResponse.HttpClientResponse, stream: Stream.Stream<MessageStreamEvent, AiError.AiError>],
    AiError.AiError
  >
}

Source

Since v4.0.0

options

Section titled “options”

Options (type alias)

Section titled “Options (type alias)”

Configuration for creating an Anthropic client.

When to use

Use when the Anthropic client settings are already available as values and should be passed directly to make or layer.

Details

These options configure the base Anthropic URL, the x-api-key authentication header, the anthropic-version header, and an optional transformation of the underlying HttpClient.

See

  • make for constructing an Anthropic client from explicit options
  • layer for providing an Anthropic client from explicit options
  • layerConfig for loading Anthropic client settings from Config

Signature

type Options = {
  /**
   * The Anthropic API key for authentication. Requests are made without authentication when this is omitted, which is
   * useful for proxied setups or testing.
   */
  readonly apiKey?: Redacted.Redacted<string> | undefined


  /**
   * The base URL for the Anthropic API. Override this to use a proxy or a different API-compatible endpoint.
   *
   * @default "https://api.anthropic.com"
   */
  readonly apiUrl?: string | undefined


  /**
   * The Anthropic API version header value. This controls which version of the API to use.
   *
   * @default "2023-06-01"
   */
  readonly apiVersion?: string | undefined


  /**
   * Optional transformer for the underlying HTTP client, such as middleware, logging, or custom request/response
   * handling.
   */
  readonly transformClient?: ((client: HttpClient.HttpClient) => HttpClient.HttpClient) | undefined
}

Source

Since v4.0.0

services

Section titled “services”

AnthropicClient (class)

Section titled “AnthropicClient (class)”

Service tag for the Anthropic client.

When to use

Use when accessing or providing the Anthropic client service through Effect’s context.

See

  • make for constructing an Anthropic client effectfully
  • layer for providing a client from explicit options
  • layerConfig for providing a client from Config

Signature

declare class AnthropicClient

Source

Since v4.0.0