Struct RenderOptions 

pub struct RenderOptions {
    pub add_generation_prompt: bool,
    pub bos_token: Option<String>,
    pub eos_token: Option<String>,
    pub tools: Vec<Value>,
    pub extra: Map<String, Value>,
}

Everything a template can read besides messages.

extra is the OpenAI-extension chat_template_kwargs passthrough: whatever the client puts there becomes a top-level template variable, which is how enable_thinking (Qwen3, gemma-4), thinking (DeepSeek), and preserve_thinking are actually driven. Values in extra never shadow messages/tools/add_generation_prompt.

Fields

add_generation_prompt: bool

bos_token: Option<String>

The vocabulary’s BOS text (<s>, <|begin_of_text|>, <bos>). Templates that print {{ bos_token }} own BOS insertion; see ferrox-server’s generate for why that does not double-add.

eos_token: Option<String>

tools: Vec<Value>

OpenAI tools array, verbatim. Passed to every template; only templates that mention tools do anything with it (see ChatTemplate::handles_tools).

extra: Map<String, Value>

Trait Implementations

impl Clone for RenderOptions

fn clone(&self) -> RenderOptions

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for RenderOptions

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

Formats the value using the given formatter.

impl Default for RenderOptions

fn default() -> RenderOptions

Returns the “default value” for a type.