Enum ContentBlock 

#[non_exhaustive]
pub enum ContentBlock {
    Text {
        text: String,
    },
    ToolUse {
        id: String,
        name: String,
        input: Value,
    },
    ToolResult {
        tool_use_id: String,
        content: String,
        is_error: bool,
    },
}

One piece of a message’s content.

A message is a list of blocks rather than a string because a single assistant turn routinely mixes prose with tool calls, and a user turn mixes prose with tool results. Flattening that to text loses the pairing between a call and its result — which is one of the concrete ways a handoff drops context.

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

Plain prose.

Fields

text: String

The prose itself.

ToolUse

The model asking for a tool to be run.

Fields

id: String

Correlates with the matching ContentBlock::ToolResult.

name: String

Which tool — a crate::tool::ToolSpec::name.

input: Value

Arguments, shaped by the tool’s declared schema.

ToolResult

The answer to a ContentBlock::ToolUse.

Fields

tool_use_id: String

The id of the ContentBlock::ToolUse this answers.

content: String

The tool’s output — or its error text — as the model will read it.

is_error: bool

The tool failed and content is its error text.

Implementations

impl ContentBlock

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

A prose block.

pub fn tool_use( id: impl Into<String>, name: impl Into<String>, input: Value, ) -> Self

A tool call: run name with input; id pairs it with its result.

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

A successful tool result, answering the call identified by tool_use_id.

pub fn tool_error( tool_use_id: impl Into<String>, content: impl Into<String>, ) -> Self

A failed tool call. Reported to the model rather than raised, so it can adapt — a tool that errors is information, not the end of the turn.

pub fn as_text(&self) -> Option<&str>

The prose in this block, if it is prose.

Trait Implementations

impl Clone for ContentBlock

fn clone(&self) -> ContentBlock

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ContentBlock

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ContentBlock

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ContentBlock

fn eq(&self, other: &ContentBlock) -> 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 ContentBlock

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 ContentBlock