Amazon Bedrock

Bedrock has two inference endpoints, and the library covers both. BedrockMantleProvider targets bedrock-mantle, the endpoint AWS recommends for new applications: OpenAI-compatible Responses and Chat Completions plus the Anthropic Messages API, all behind a Bedrock API key. BedrockModel targets bedrock-runtime, the Converse API, which is where guardrails, cross-region inference profiles, and SigV4 signing live.

bedrock-mantle

let bedrock = BedrockMantleProvider(region: "us-east-1")

let responses = bedrock("openai.gpt-oss-120b")
let chat = bedrock.chat("deepseek.v3-2")
let messages = bedrock.messages("anthropic.claude-sonnet-4-6-v1")

callAsFunction (and languageModel(_:)) returns the Responses-API model, which is the endpoint's recommended surface. All three factories report provider == "bedrock" for telemetry.

The key comes from AWS_BEARER_TOKEN_BEDROCK or an explicit apiKey:. The OpenAI-compatible surfaces send it as Authorization: Bearer, the Messages surface as x-api-key with anthropic-version: 2023-06-01 — the same headers AWS documents. Base URLs derive from the region (https://bedrock-mantle.{region}.api.aws, then /v1 or /anthropic/v1) unless you pass baseURL:; a baseURL that already ends in /v1 or /anthropic/v1 is normalized, so a gateway origin works either way.

Mantle model ids carry no region prefix — there are no cross-region inference profiles on this endpoint. Use anthropic.claude-sonnet-4-6-v1, not us.anthropic.claude-sonnet-4-6-v1.

Responses-API reasoning effort rides providerOptions here, because the unified reasoning: knob keys off OpenAI's own model-id shapes:

let result = try await generateText(
  model: bedrock("openai.gpt-oss-120b"),
  messages: [.user("Plan the migration.")],
  providerOptions: ["reasoning": ["effort": "high"], "store": false]
)

bedrock.chat(...) and bedrock.messages(...) take the unified reasoning: parameter directly — chat completions map it to reasoning_effort, and Claude ids map to the same thinking tiers as the Anthropic pack.

bedrock-runtime

let model = BedrockModel(
  "anthropic.claude-sonnet-4-5-20250929-v1:0",
  region: "us-east-1"
)

Two auth modes. The simplest is Bedrock's API-key auth via AWS_BEARER_TOKEN_BEDROCK. For IAM credentials, pass accessKeyID: / secretAccessKey: (and sessionToken: for temporary creds), or set AWS_ACCESS_KEY_ID / AWS_SECRET_ACCESS_KEY / AWS_SESSION_TOKEN — the request is then SigV4-signed for the region. When both are present, SigV4 wins. The base URL derives from the region (https://bedrock-runtime.{region}.amazonaws.com) unless you pass one.

let model = BedrockModel(
  "anthropic.claude-sonnet-4-5-20250929-v1:0",
  region: "us-east-1",
  accessKeyID: "AKIA…",
  secretAccessKey: "…"
)

Features

• Tools, structured output, and vision over the Converse API.
• Responses stream in AWS's binary event-stream framing; the library decodes it natively.
• usage.cachedInputTokens is populated where the model reports cache reads; guardrail trace and cacheWriteInputTokens arrive on result.providerMetadata["bedrock"].

Models

The reasoning parameter translates by model-id family:

Model ids are Bedrock's prefixed forms, e.g. anthropic.claude-sonnet-4-5-20250929-v1:0 or an inference profile like us.anthropic.claude-sonnet-4-5-20250929-v1:0. Amazon's own Nova line (as of July 2026): nova-2-lite (December 2025), plus nova-pro, nova-lite, and nova-micro.