Module content 

Content block types used within Claude messages.

Claude’s protocol carries heterogeneous content as a tagged union. This module provides the ContentBlock enum (used inside assistant messages) and UserContent (used when constructing user turns).

Serde representation

Both enums use an externally-tagged representation via #[serde(tag = "type", rename_all = "snake_case")], matching the NDJSON format produced by the Claude Code CLI.

Example

use claude_cli_sdk::types::content::{UserContent, ContentBlock};

let msg = UserContent::text("Hello, Claude!");
let with_image = UserContent::image_url("https://example.com/img.png", "image/png");

Structs

Base64ImageSource

Inline base64 image data.

ImageBlock

An image content block, supporting both base64-encoded and URL sources.

TextBlock

A plain-text content block.

ThinkingBlock

Extended thinking produced by the model (chain-of-thought).

ToolResultBlock

The result of a tool invocation, returned as part of a user turn.

ToolUseBlock

A tool invocation requested by the model.

UrlImageSource

A URL-referenced image.

Enums

ContentBlock

A single block of content within an assistant message.

ImageSource

The source of an image — either inline base64 data or a remote URL.

ToolResultContent

Either a plain string or a list of content blocks — both are valid in the protocol.

UserContent

Content that can be sent as part of a user turn.

Constants

ALLOWED_IMAGE_MIME_TYPES

MIME types accepted by the Claude API for image inputs.

MAX_IMAGE_BASE64_BYTES

Maximum allowed size for a base64-encoded image payload (15 MiB).