Implementation:Anthropics Anthropic sdk python BetaContentBlockParam

Knowledge Sources	Anthropic SDK Python
Domains	API_Types, Beta_Features
Last Updated	2026-02-15 12:00 GMT

Overview

BetaContentBlockParam is a central union type alias representing all possible content block parameter types that can be sent as input to the beta API. It covers 20 distinct block param variants plus the response-side BetaContentBlock union itself.

Description

BetaContentBlockParam is defined as a TypeAlias using typing.Union. Unlike its response counterpart BetaContentBlock, this union does not use a discriminator annotation because it is designed for request input rather than response deserialization.

The union includes input-oriented param types that mirror (and extend) the response block types. Notably, this union includes types that only appear in requests but never in responses, such as:

• BetaImageBlockParam -- For sending image content
• BetaRequestDocumentBlockParam -- For sending document content
• BetaToolResultBlockParam -- For returning tool results to the model
• BetaSearchResultBlockParam -- For providing search results
• BetaRequestMCPToolResultBlockParam -- For providing MCP tool results

The union also includes BetaContentBlock itself as a final member, which means you can pass response content blocks directly back into a new request without conversion.

Usage

Use BetaContentBlockParam when constructing the content field of message parameters sent to the beta API. This is the type expected for individual content items within user or assistant message params. It allows mixing text, images, documents, tool results, and other content types in a single message.

Code Reference

Source Location

• Repository: Anthropic SDK Python
• File: src/anthropic/types/beta/beta_content_block_param.py

Signature

BetaContentBlockParam: TypeAlias = Union[
    BetaTextBlockParam,
    BetaImageBlockParam,
    BetaRequestDocumentBlockParam,
    BetaSearchResultBlockParam,
    BetaThinkingBlockParam,
    BetaRedactedThinkingBlockParam,
    BetaToolUseBlockParam,
    BetaToolResultBlockParam,
    BetaServerToolUseBlockParam,
    BetaWebSearchToolResultBlockParam,
    BetaWebFetchToolResultBlockParam,
    BetaCodeExecutionToolResultBlockParam,
    BetaBashCodeExecutionToolResultBlockParam,
    BetaTextEditorCodeExecutionToolResultBlockParam,
    BetaToolSearchToolResultBlockParam,
    BetaMCPToolUseBlockParam,
    BetaRequestMCPToolResultBlockParam,
    BetaContainerUploadBlockParam,
    BetaCompactionBlockParam,
    BetaContentBlock,
]

Import

from anthropic.types.beta import BetaContentBlockParam

I/O Contract

BetaContentBlockParam is a pure type alias for request construction. Each variant is a TypedDict with a required type field.

Variant Type	Purpose	Direction
BetaTextBlockParam	Send text content	Request only
BetaImageBlockParam	Send image content (base64 or URL)	Request only
BetaRequestDocumentBlockParam	Send document content	Request only
BetaSearchResultBlockParam	Provide search results	Request only
BetaThinkingBlockParam	Pass back thinking blocks	Request (continuation)
BetaRedactedThinkingBlockParam	Pass back redacted thinking	Request (continuation)
BetaToolUseBlockParam	Pass back tool use blocks	Request (continuation)
BetaToolResultBlockParam	Return tool execution results	Request only
BetaServerToolUseBlockParam	Pass back server tool use	Request (continuation)
BetaWebSearchToolResultBlockParam	Pass back web search results	Request (continuation)
BetaWebFetchToolResultBlockParam	Pass back web fetch results	Request (continuation)
BetaCodeExecutionToolResultBlockParam	Pass back code execution results	Request (continuation)
BetaBashCodeExecutionToolResultBlockParam	Pass back bash execution results	Request (continuation)
BetaTextEditorCodeExecutionToolResultBlockParam	Pass back text editor results	Request (continuation)
BetaToolSearchToolResultBlockParam	Pass back tool search results	Request (continuation)
BetaMCPToolUseBlockParam	Pass back MCP tool use	Request (continuation)
BetaRequestMCPToolResultBlockParam	Return MCP tool results	Request only
BetaContainerUploadBlockParam	Pass back container upload	Request (continuation)
BetaCompactionBlockParam	Pass back compaction blocks	Request (continuation)
BetaContentBlock	Pass response blocks directly	Bidirectional

Usage Examples

Building a Multi-Modal Message

from anthropic.types.beta import BetaContentBlockParam

content: list[BetaContentBlockParam] = [
    {
        "type": "image",
        "source": {
            "type": "base64",
            "media_type": "image/png",
            "data": "<base64-encoded-data>",
        },
    },
    {
        "type": "text",
        "text": "What do you see in this image?",
    },
]

Passing Tool Results Back

from anthropic.types.beta import BetaContentBlockParam

tool_result: BetaContentBlockParam = {
    "type": "tool_result",
    "tool_use_id": "toolu_01abc123",
    "content": "The current temperature in San Francisco is 62F.",
}

Forwarding Response Blocks Into a New Request

from anthropic.types.beta import BetaContentBlockParam, BetaMessage

def continue_conversation(previous_response: BetaMessage) -> list[BetaContentBlockParam]:
    # BetaContentBlock is a valid BetaContentBlockParam variant,
    # so response blocks can be passed directly
    return list(previous_response.content)

Related Pages

• Anthropics_Anthropic_sdk_python_BetaContentBlock -- The response-side counterpart of this union type
• Anthropics_Anthropic_sdk_python_BetaMessage -- The response model whose content field uses BetaContentBlock
• Anthropics_Anthropic_sdk_python_MessageCreateParams -- Uses content block params in message construction
• Anthropics_Anthropic_sdk_python_ToolResultBlockParam -- Stable counterpart for tool result params