Alloy.Provider.Anthropic (alloy v0.12.4)

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Provider for Anthropic's Claude Messages API.

Uses Req for HTTP calls. Since Anthropic's wire format uses content blocks (the most expressive format), this provider has the simplest normalization.

Config

Required:

  • :api_key - Anthropic API key
  • :model - Model name (e.g., "claude-opus-4-6", "claude-sonnet-4-6", "claude-haiku-4-5")

Optional:

  • :max_tokens - Max output tokens (default: 4096)
  • :system_prompt - System prompt string
  • :api_url - Base URL (default: "https://api.anthropic.com")
  • :api_version - API version header (default: "2023-06-01")
  • :extra_headers - Additional headers as [{name, value}]
  • :extra_body - Additional request body fields, merged last
  • :req_options - Additional options passed to Req (useful for testing)
  • :extended_thinking - Enable extended thinking. Pass a keyword list with :budget_tokens (e.g., [budget_tokens: 5000]). Thinking blocks are returned in the message content and must be round-tripped verbatim in subsequent turns (Anthropic requires the signature field).
  • :on_event - Streaming event callback (event -> :ok). Called for each streaming delta. When used via Server.stream_chat/4, event is a normalized envelope map:
    • %{v: 1, seq:, correlation_id:, turn:, ts_ms:, event: :text_delta, payload: text}
    • %{v: 1, seq:, correlation_id:, turn:, ts_ms:, event: :thinking_delta, payload: text} Pass via Server.stream_chat/4 opts: on_event: fn event -> ... end. Note: direct callers of Alloy.Provider.Anthropic.stream/4 (without Turn) receive provider-native tuples (for example {:thinking_delta, text}).

Example

Alloy.run("What is Elixir?",
  provider: {Alloy.Provider.Anthropic,
    api_key: System.get_env("ANTHROPIC_API_KEY"),
    model: "claude-sonnet-4-6"
  }
)

Summary

Types

config()

Configuration for the Anthropic provider. See the module doc for field semantics.

Functions

stream(messages, tool_defs, config, on_chunk)

Stream a completion using Anthropic's SSE streaming API.

Types

config()

@type config() :: %{
  :api_key => String.t(),
  :model => String.t(),
  optional(:max_tokens) => pos_integer(),
  optional(:system_prompt) => String.t(),
  optional(:api_url) => String.t(),
  optional(:api_version) => String.t(),
  optional(:extra_headers) => [{String.t(), String.t()}],
  optional(:extra_body) => map(),
  optional(:req_options) => keyword(),
  optional(:extended_thinking) => keyword(),
  optional(:on_event) => (term() -> :ok),
  optional(:cache) => boolean(),
  optional(:memory) => {module(), term()}
}

Configuration for the Anthropic provider. See the module doc for field semantics.

Functions

stream(messages, tool_defs, config, on_chunk)

@spec stream(
  [Alloy.Message.t()],
  [Alloy.Provider.tool_def()],
  config(),
  (String.t() -> :ok)
) ::
  {:ok, Alloy.Provider.completion_response()} | {:error, term()}

Stream a completion using Anthropic's SSE streaming API.

Calls on_chunk for each text delta as it arrives. Accumulates all content blocks and returns the same {:ok, completion_response()} shape as complete/3 once the stream finishes.