Struct ModelOptions 

pub struct ModelOptions {
    pub temperature: Option<f32>,
    pub max_tokens: Option<u32>,
    pub extra: BTreeMap<String, Value>,
    pub headers: BTreeMap<String, String>,
    pub structured: Option<Value>,
}

Model options for one conversation.

Common parameters are provided as typed fields (temperature / max tokens, where None means vendor default); vendor-specific or framework-unknown parameters go into extra and request headers go into headers — both are passed through to the vendor verbatim, so users can reach new parameters and endpoint requirements without waiting for a framework update:

use molo::ModelOptions;

let mut options = ModelOptions::default();
options.extra.insert("top_p".into(), serde_json::json!(0.9));
options.headers.insert("x-trace-id".into(), "abc-123".into());

Explicit settings win

When an extra key names a parameter the framework also manages (temperature / max_tokens / response_format), the extra value is the one sent: an explicitly written wire field is a deliberate override, and the typed field is dropped for that request instead of being merged (merging would emit the JSON key twice).

The request envelope is not a parameter: extra entries named messages / tools (the conversation the framework is driving), stream / stream_options (the delivery shape) and model (bound at provider construction and reported in run summaries — a per-request override would make those summaries name a model that did not answer) are ignored, since they would replace the request rather than tune it.

Fields

temperature: Option<f32>

Sampling temperature; None means vendor default.

max_tokens: Option<u32>

Maximum number of tokens for the reply; None means vendor default.

extra: BTreeMap<String, Value>

Vendor extension parameters: keys are wire request field names, serialized into the request body verbatim.

headers: BTreeMap<String, String>

Extra HTTP request headers, sent by HTTP providers alongside the headers the framework sets itself.

For endpoints that require more than the request body: gateways and proxies commonly route or trace by header (a tenant / project id, a gateway token, an x-trace-id), and some vendors authenticate with a header name of their own (api-key, x-api-key).

use molo::ModelOptions;

let mut options = ModelOptions::default();
options.headers.insert("api-key".into(), "secret".into());
options.headers.insert("x-trace-id".into(), "abc-123".into());

Semantics

• Names / values are taken as given (HTTP matches names case-insensitively); an entry that is not a valid HTTP header is reported by the provider as ProviderError::Protocol rather than dropped silently, since a header that quietly never arrives is worse than a failed request.
• An explicit Authorization wins over the provider’s api key: the endpoint sees the caller’s value and the provider does not add a bearer token of its own (two Authorization headers would be ambiguous — see the adapter’s request construction). Content-Type is likewise the caller’s when set.
• Transport-framing headers stay framework-owned: Content-Length / Transfer-Encoding / Connection / Host / Upgrade describe the request the framework actually sends, so entries with those names are ignored (a stale Content-Length corrupts the framing of the body).
• Values are masked in Debug output (names stay visible), so a credential carried in a header does not leak through {:?} logging; the map itself still prints plainly for deliberate inspection.

Providers that do not speak HTTP ignore this field.

structured: Option<Value>

Structured output: the final answer must be JSON conforming to this JSON Schema document (the serialized RootSchema produced by schemars, or a hand-written schema).

Two layers of semantics:

• Provider side: compatible endpoints receive it via response_format to best-effort constrain the model (the OpenAI-compatible json_schema shape; unsupported endpoints ignore it or error);
• Agent side: the final answer is validated framework-side, and on mismatch the validation error is fed back to the model for a retry (counted against the turn budget by the agent runtime’s structured output support).

None = free-form text reply.

Trait Implementations

impl Clone for ModelOptions

fn clone(&self) -> ModelOptions

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ModelOptions

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

Formats the value using the given formatter.

impl Default for ModelOptions

fn default() -> ModelOptions

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for ModelOptions

fn deserialize<__D>( __deserializer: __D, ) -> Result<ModelOptions, <__D as Deserializer<'de>>::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl PartialEq for ModelOptions

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

Equality operator ==.

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

Inequality operator !=.

impl Serialize for ModelOptions

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

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for ModelOptions