AWS Bedrock¶

The Converse API: Bedrock's unified interface, where one request shape serves Claude, Nova, Llama, Mistral, and DeepSeek alike. Generation never uses InvokeModel and its per-model request bodies; only embeddings do, because Converse has no embeddings surface.

streaming structured output tool calls reasoning cache accounting

Setup¶

Two ways to authenticate. A Bedrock API key is the simplest:

import anyinfer as ai

client = ai.Client(
    [
        ai.ProviderSettings.of(
            "bedrock",
            api_key="env://AWS_BEARER_TOKEN_BEDROCK",
            options={"region": "us-east-1"},
        ),
    ]
)

result = client.generate(prompt, target="bedrock:us.anthropic.claude-sonnet-4-5")

Or AWS credentials, which are SigV4-signed per request:

ai.ProviderSettings.of("bedrock", options={"region": "us-west-2"})

With no explicit key, credentials are resolved in order: explicit aws_access_key_id / aws_secret_access_key options, then boto3's chain if it is installed (it knows about SSO caches, instance metadata, and profiles), then AWS_ACCESS_KEY_ID and friends from the environment. Neither boto3 nor any other SDK is a dependency; signing is implemented against the standard library.

aws-bedrock: and amazon-bedrock: are accepted aliases.

Model Ids¶

Bedrock accepts base model ids, inference-profile ids, and full ARNs. Cross-region inference profiles carry a region prefix:

client.generate(prompt, target="bedrock:us.anthropic.claude-sonnet-4-5")
client.generate(prompt, target="bedrock:amazon.nova-pro-v1:0")

Ids containing colons work because targets split on the first colon only.

Binary Streaming¶

ConverseStream answers with AWS's vnd.amazon.eventstream framing and offers no SSE or JSON alternative. AnyInfer decodes it, including verifying both frame checksums; from the application's side it is an ordinary stream:

with client.stream(prompt, target="bedrock:us.anthropic.claude-sonnet-4-5") as stream:
    for event in stream:
        if isinstance(event, ai.TextDelta):
            print(event.text, end="", flush=True)
    print(stream.result.usage.input_tokens)

Why usage only appears at the end

Bedrock sends token counts only in the terminal metadata event, after messageStop. A client that stopped at the stop reason would report zero tokens for every request; AnyInfer reads through to the metadata frame.

Structured Output¶

Converse has no response-format field, so a schema is emulated as a single forced tool call (the same approach the Anthropic adapter takes, because the API genuinely constrains tool input):

result = client.generate(article, target="bedrock:amazon.nova-pro-v1:0", schema=SUMMARY)
print(result.structured["headline"])
print(result.structured_mechanism)  # "json_schema"

See structured output for how mechanisms are chosen and validated.

Reasoning¶

Converse has no reasoning parameter of its own; extended thinking is a model-specific field, so normalized effort travels in additionalModelRequestFields:

result = client.generate(prompt, target="bedrock:us.anthropic.claude-sonnet-4-5", reasoning="high")

Thinking text arrives as ReasoningDelta events and stays out of result.text. Models without extended thinking ignore the field.

Provider-Specific Parameters¶

Anything Converse does not model (Claude's top_k, guardrail configuration, a service tier) passes through provider_options, under keys such as additionalModelRequestFields and guardrailConfig. See the escape hatch.

Discovery and Health¶

Discovery reads the Bedrock control plane, a different host than the runtime. An account without bedrock:ListFoundationModels gets an empty list rather than an error; a permission gap should not make the provider look broken.

Health makes no network call at all: every runtime endpoint costs a generation, and the control plane may be denied by policy even when inference works perfectly. It reports whether credentials are present.

Pricing¶

Bedrock prices per model and per region; the bundled table carries the common us-east-1 on-demand rates for the Nova family and Claude, and capability_overrides covers rates that differ; see cost and spending.

Embeddings¶

Since Converse has no embeddings surface, embeddings go through the older InvokeModel action (a separate code path from generation, sharing only auth and addressing):

result = client.embed(
    ["first text", "second text"],
    target="bedrock:amazon.titan-embed-text-v2:0",
)

Titan Text Embeddings V2 accepts one inputText per call, so the adapter declares max_batch_inputs=1 and the core's batching policy fans a multi-text call into one request per input. dimensions= requests native truncation to 1024 (default), 512, or 256; the model has no input-intent concept.

Cohere Embed v3 runs on the same action, under a different body shape selected by the cohere. model-id prefix. It is batch-capable (up to 96 texts per call) and requires input_type:

result = client.embed(
    ["first text", "second text"],
    target="bedrock:cohere.embed-english-v3",
    input_type="document",
)

Bedrock's Cohere embed response reports no token usage, so result.usage is None, never a guessed value.

Reranking¶

Rerank is a third action entirely: bedrock-agent-runtime's POST /rerank, a different host than InvokeModel/Converse (though SigV4-signed under the same bedrock service name). It is model-agnostic at the wire level: the same request/response shape serves both amazon.rerank-v1:0 and cohere.rerank-v3-5:0, selected only by the modelArn the adapter builds from the model id. Up to 1,000 documents per call; top_n maps to the action's native numberOfResults. No usage/search-unit field is reported.

result = client.rerank(
    query="What is Amazon Bedrock?",
    documents=["Amazon Bedrock is a fully managed service.", "Amazon S3 is storage."],
    target="bedrock:cohere.rerank-v3-5:0",
)

Multimodal Inputs¶

Converse image, document, and audio blocks are used directly. Inline inputs are base64; remote image/document references must be S3 URIs. The selected model still decides which block types it accepts.

Wire Contract¶

For the exact request/response fields this adapter depends on, see contracts/bedrock.md.