Enum UserBlock 

#[non_exhaustive]
pub enum UserBlock {
    Text {
        text: String,
        cache_control: Option<CacheControl>,
    },
    ToolResult {
        call_id: String,
        content: ToolResultContent,
        cache_control: Option<CacheControl>,
    },
    Image {
        source: Source,
        cache_control: Option<CacheControl>,
    },
    Document {
        source: Source,
        cache_control: Option<CacheControl>,
    },
}

One block inside a Message::User turn.

Free user text, tool results, and inline media (images, documents) all live here because providers route tool results — and the rest of the multimodal surface — back through the user role on the wire.

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Text

Free user text.

Fields

text: String

Text content.

cache_control: Option<CacheControl>

Per-request cache hint. #[serde(skip)] — the cache breakpoint is a per-call directive to the provider, not part of the persisted conversation state, so it is dropped on snapshot round-trip and restored as None.

ToolResult

Result of a tool invocation paired with the assistant AssistantBlock::ToolCall of the previous turn (matched by id).

Fields

call_id: String

Matches the id on the originating AssistantBlock::ToolCall.

content: ToolResultContent

The tool’s reply. content.is_error flags tool-reported failures separately from the block list, so an error reply can still carry images.

cache_control: Option<CacheControl>

See UserBlock::Text::cache_control.

Image

Image content rendered inline. Adapters map this to the provider’s image content type (Anthropic image, Chat Completions image_url). Adapters that cannot represent the chosen Source (e.g. a Chat Completions deployment with no vision support) surface a typed error.

Fields

source: Source

Image source: base64, URL, or provider-side file ID.

cache_control: Option<CacheControl>

See UserBlock::Text::cache_control.

Document

Document content rendered inline (PDF and similar). Anthropic has a dedicated document content type; Chat Completions does not, so the Azure adapter surfaces a typed UnsupportedContent error and callers downgrade via ChatMiddleware::on_chat_request if they want a text substitute.

Fields

source: Source

Document source: base64, URL, or provider-side file ID.

cache_control: Option<CacheControl>

See UserBlock::Text::cache_control.

Implementations

impl UserBlock

pub fn text(text: impl Into<String>) -> Self

Build a UserBlock::Text with no cache breakpoint.

pub fn tool_result( call_id: impl Into<String>, content: impl Into<ToolResultContent>, ) -> Self

Build a UserBlock::ToolResult with no cache breakpoint. The content argument is anything that converts into ToolResultContent — String and &str produce a single text block with is_error = false. Use ToolResultContent::error to flag a tool-reported failure or ToolResultContent::from_blocks to build a multi-block reply.

pub fn image(source: Source) -> Self

Build a UserBlock::Image with no cache breakpoint.

pub fn document(source: Source) -> Self

Build a UserBlock::Document with no cache breakpoint.

pub fn with_cache_control(self, cache_control: Option<CacheControl>) -> Self

Builder-style helper: set or replace the cache breakpoint on this block. Use None to clear.

pub fn cache_control(&self) -> Option<&CacheControl>

Read the current cache breakpoint, if any.

Trait Implementations

impl Clone for UserBlock

fn clone(&self) -> UserBlock

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for UserBlock

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for UserBlock

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for UserBlock

fn eq(&self, other: &UserBlock) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Serialize for UserBlock

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for UserBlock