Struct ThinkingBlock 

pub struct ThinkingBlock {
    pub thinking: String,
    pub signature: Option<String>,
}

Thinking block (extended thinking mode)

Contains Claude’s reasoning process when extended thinking mode is enabled. This block is OPTIONAL and only appears when the user explicitly enables extended thinking in their Claude settings.

Example

{
  "type": "thinking",
  "thinking": "The user is asking about...",
  "signature": "ErQYCkYICxgCKkA1FuCoAqSF..."
}

Usage

• Available when extended thinking mode is enabled
• Contains full reasoning process
• Includes cryptographic signature for verification
• Makes Claude competitive with Gemini for reasoning extraction

Frequency

Variable - only present when extended thinking is enabled by user

Fields

thinking: String

Full reasoning text

Contains Claude’s complete thought process, including:

• Analysis of the request
• Consideration of alternatives
• Decision-making rationale
• Context evaluation

signature: Option<String>

Cryptographic signature for verification

Used to verify the authenticity of the thinking content. Optional field that may not be present in all thinking blocks.

Trait Implementations

impl Clone for ThinkingBlock

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ThinkingBlock

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for ThinkingBlock

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

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for ThinkingBlock

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

where __S: Serializer,

Serialize this value into the given Serde serializer.