Enum FinishReason 

pub enum FinishReason {
    Stop,
    ToolUse,
    Length,
    ContentFilter,
    Other(String),
}

Why a model stopped generating, normalized across providers.

Providers report this as Anthropic stop_reason, OpenAI finish_reason, or Gemini finishReason. It used to be parsed and discarded, so a max_tokens truncation or a content_filter/safety block looked identical to a clean finish. The agent loop now inspects it: Length surfaces a truncation notice, and an empty ContentFilter finish becomes an error.

Variants

Stop

Normal end of turn (end_turn, stop, stop_sequence, STOP).

ToolUse

Stopped to call a tool (tool_use, tool_calls).

Length

Hit the output token limit — the response is truncated.

ContentFilter

Blocked by a content filter / safety system / recitation check.

Other(String)

A reason we don’t specifically model; carries the raw provider string.

Trait Implementations

impl Clone for FinishReason

fn clone(&self) -> FinishReason

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for FinishReason

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for FinishReason

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for FinishReason

impl PartialEq for FinishReason

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

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 FinishReason