strands.models.bedrock

AWS Bedrock model provider.

• Docs: https://aws.amazon.com/bedrock/

BedrockModel

class BedrockModel(Model)

Defined in: src/strands/models/bedrock.py:60

AWS Bedrock model provider implementation.

The implementation handles Bedrock-specific features such as:

• Tool configuration for function calling
• Guardrails integration
• Caching points for system prompts and tools
• Streaming responses
• Context window overflow detection

BedrockConfig

class BedrockConfig(TypedDict)

Defined in: src/strands/models/bedrock.py:72

Configuration options for Bedrock models.

Attributes:

• additional_args - Any additional arguments to include in the request
• additional_request_fields - Additional fields to include in the Bedrock request
• additional_response_field_paths - Additional response field paths to extract
• cache_prompt - Cache point type for the system prompt (deprecated, use cache_config)
• cache_config - Configuration for prompt caching. Use CacheConfig(strategy=“auto”) for automatic caching.
• cache_tools - Cache point type for tools
• guardrail_id - ID of the guardrail to apply
• guardrail_trace - Guardrail trace mode. Defaults to enabled.
• guardrail_version - Version of the guardrail to apply
• guardrail_stream_processing_mode - The guardrail processing mode
• guardrail_redact_input - Flag to redact input if a guardrail is triggered. Defaults to True.
• guardrail_redact_input_message - If a Bedrock Input guardrail triggers, replace the input with this message.
• guardrail_redact_output - Flag to redact output if guardrail is triggered. Defaults to False.
• guardrail_redact_output_message - If a Bedrock Output guardrail triggers, replace output with this message.
• guardrail_latest_message - Flag to send only the lastest user message to guardrails. Defaults to False.
• max_tokens - Maximum number of tokens to generate in the response
• model_id - The Bedrock model ID (e.g., “us.anthropic.claude-sonnet-4-20250514-v1:0”)
• include_tool_result_status - Flag to include status field in tool results. True includes status, False removes status, “auto” determines based on model_id. Defaults to “auto”.
• stop_sequences - List of sequences that will stop generation when encountered
• streaming - Flag to enable/disable streaming. Defaults to True.
• temperature - Controls randomness in generation (higher = more random)
• top_p - Controls diversity via nucleus sampling (alternative to temperature)

__init__

def __init__(*,
             boto_session: boto3.Session | None = None,
             boto_client_config: BotocoreConfig | None = None,
             region_name: str | None = None,
             endpoint_url: str | None = None,
             **model_config: Unpack[BedrockConfig])

Defined in: src/strands/models/bedrock.py:125

Initialize provider instance.

Arguments:

• boto_session - Boto Session to use when calling the Bedrock Model.
• boto_client_config - Configuration to use when creating the Bedrock-Runtime Boto Client.
• region_name - AWS region to use for the Bedrock service. Defaults to the AWS_REGION environment variable if set, or “us-west-2” if not set.
• endpoint_url - Custom endpoint URL for VPC endpoints (PrivateLink)
• **model_config - Configuration options for the Bedrock model.

update_config

@override
def update_config(**model_config: Unpack[BedrockConfig]) -> None

Defined in: src/strands/models/bedrock.py:192

Update the Bedrock Model configuration with the provided arguments.

Arguments:

• **model_config - Configuration overrides.

get_config

@override
def get_config() -> BedrockConfig

Defined in: src/strands/models/bedrock.py:202

Get the current Bedrock Model configuration.

Returns:

The Bedrock model configuration.

stream

@override
async def stream(messages: Messages,
                 tool_specs: list[ToolSpec] | None = None,
                 system_prompt: str | None = None,
                 *,
                 tool_choice: ToolChoice | None = None,
                 system_prompt_content: list[SystemContentBlock] | None = None,
                 **kwargs: Any) -> AsyncGenerator[StreamEvent, None]

Defined in: src/strands/models/bedrock.py:736

Stream conversation with the Bedrock model.

This method calls either the Bedrock converse_stream API or the converse API based on the streaming parameter in the configuration.

Arguments:

• messages - List of message objects to be processed by the model.
• tool_specs - List of tool specifications to make available to the model.
• system_prompt - System prompt to provide context to the model.
• tool_choice - Selection strategy for tool invocation.
• system_prompt_content - System prompt content blocks to provide context to the model.
• **kwargs - Additional keyword arguments for future extensibility.

Yields:

Model events.

Raises:

• ContextWindowOverflowException - If the input exceeds the model’s context window.
• ModelThrottledException - If the model service is throttling requests.

structured_output

@override
async def structured_output(
        output_model: type[T],
        prompt: Messages,
        system_prompt: str | None = None,
        **kwargs: Any) -> AsyncGenerator[dict[str, T | Any], None]

Defined in: src/strands/models/bedrock.py:1047

Get structured output from the model.

Arguments:

• output_model - The output model to use for the agent.
• prompt - The prompt messages to use for the agent.
• system_prompt - System prompt to provide context to the model.
• **kwargs - Additional keyword arguments for future extensibility.

Yields:

Model events with the last being the structured output.