Struct NativeLoopConfig 

pub struct NativeLoopConfig {
    pub model: Option<String>,
    pub exclude_models: Vec<String>,
    pub max_iterations: u32,
    pub max_turns_per_iteration: u32,
    pub max_tokens_per_turn: usize,
    pub prompt_overlay: Option<String>,
    pub deadline: Arc<SessionDeadline>,
    pub auth_gate: Option<Arc<dyn AuthGate>>,
    pub can_adjudicate_no_change: bool,
    pub auth_wait: Duration,
    pub baseline_captures: BaselineCaptures,
}

Tuning for the native loop.

Fields

model: Option<String>

Pinned model id; None routes adaptively (TaskHint::Code).

exclude_models: Vec<String>

Models the adaptive arm must not use. Ignored when Self::model is pinned: a caller’s explicit model is either honored or refused by its own admission gate, never silently routed around.

max_iterations: u32

Contract-evaluation rounds before giving up.

max_turns_per_iteration: u32

Model turns within one iteration before forcing evaluation.

max_tokens_per_turn: usize

Generation budget per turn.

prompt_overlay: Option<String>

Extra guidance appended to the system prompt, set by the harness evolution loop (car#708). None = the byte-identical prompt the coder used before overlays existed.

deadline: Arc<SessionDeadline>

The session’s absolute deadline, SHARED with every other rung of the fallback ladder. An Arc rather than a value so a rung cannot restart a clock it does not own — the defect that made the first version a per-loop ceiling calling itself a session one.

auth_gate: Option<Arc<dyn AuthGate>>

Lets a session blocked on sign-in wait for the human rather than dying. None keeps the previous behaviour byte for byte.

can_adjudicate_no_change: bool

Whether this caller can adjudicate a no-change nomination — i.e. it holds the baseline results, the contract’s provenance and the mutation ledger, and will run super::no_change::evaluate_nomination on whatever the loop hands back.

The report_no_change tool is offered ONLY when this is set. A caller that cannot judge a nomination must not invite one: LoopOutcome would come back neither green nor failed, and a caller not looking for that third shape reads it as an ordinary red and silently discards the finding. Advertising a tool nobody can honour is worse than not having it.

Defaults to false, which is the correct answer for every caller that has not been taught the third shape — this is a capability declaration, not a behaviour switch.

auth_wait: Duration

How long to wait for the human to re-authenticate before giving up.

Generous because it bounds a person, not a process — they may be away from the machine. The session deadline still applies on top, so this can never extend a run past its own ceiling.

baseline_captures: BaselineCaptures

The session-start baseline captures differential checks compare against (car#1067). Empty when the contract declares none — and under an empty map a differential check fails closed with a “never captured” message rather than passing silently.

Implementations

impl NativeLoopConfig

pub fn merge_harness(&mut self, h: &HarnessConfig)

Fold the general harness knobs the Evolution Agent tunes (car_memgine::HarnessConfig) onto the coder’s own budgets, so a harness patch applied through evolution.run’s gated path actually changes coder behavior. The coder’s native loop does NOT read HarnessConfig directly (it lives on the general car_engine::Runtime executor), so without this an applied patch would be inert and the A/B improvement loop could never converge. Mapping: planning_max_replans (how many replan/repair rounds the runtime grants) → the coder’s max_iterations (contract-eval repair rounds); max_retries (per-action retry budget) → a floor on max_turns_per_iteration. Only ever RAISES a budget — a harness fix grants headroom; it never starves the coder below its base config.

The session wall clock (deadline) is deliberately NOT raised here. It is an operator-owned safety ceiling, not a tuning knob, and the Evolution Agent granting itself more wall time would defeat the one bound that stops a runaway session. The consequence is real and worth stating: a patch raising max_iterations 8 -> 16 can be capped by a wall clock the harness cannot touch, so a converged-looking A/B result may in fact have been cut off. Raise max_session_wall_secs in ~/.car/coder.toml when running long-budget experiments.

Trait Implementations

impl Clone for NativeLoopConfig

fn clone(&self) -> NativeLoopConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for NativeLoopConfig

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

Formats the value using the given formatter.

impl Default for NativeLoopConfig

fn default() -> Self

Returns the “default value” for a type.