Struct EngineConfig 

pub struct EngineConfig {

    pub model: String,
    pub max_tokens: u32,
    pub max_turns: i64,
    pub thinking: bool,
    pub cache_static: bool,
    pub cache_ttl: CacheTtl,
    pub fallback_models: Vec<String>,
    pub tool_failure_budget: u32,
    pub context_window: u64,
    pub fast_model: Option<String>,
    pub compaction_reset: bool,
    pub show_context_pct: bool,
    pub evict_threshold_tokens: u64,
    /* private fields */
}

Fields

model: String

max_tokens: u32

max_turns: i64

Model samples one prompt may spend before the turn is cut short with Outcome::TurnLimit. Every tool round-trip costs one, so this is a step budget for the agent loop, not a count of conversational turns.

Negative = unlimited: the turn runs until the model stops on its own, the context fills, a tool budget trips, or the user cancels. That is a deliberate opt-in — the bound is what keeps an unattended (Auto/DontAsk) run from looping on the owner’s money, so removing it should be a choice, never a default.

thinking: bool

cache_static: bool

cache_ttl: CacheTtl

The lifetime compose_request asks explicit-cache breakpoints for when cache_static is set (CachePolicy::Static { prefix_ttl } — consumed by the Anthropic serializer’s prefix and rolling-anchor markers; the latest marker always renders plain regardless). Default FiveMinutes; long-lived human-supervised surfaces (hotl tui, hotl acp, hotl bg/attach) raise it to OneHour after scaffold() returns, and sub-agent children pin it back to FiveMinutes explicitly in HotlChildBuilder::spawn_child.

fallback_models: Vec<String>

Availability-only fallback models (≤3 total — RELIABILITY.md).

tool_failure_budget: u32

Consecutive failures of one tool before the turn stops.

context_window: u64

Model context window in tokens; compaction triggers at 80% (M2).

fast_model: Option<String>

Housekeeping model (compaction summarize); defaults to model.

compaction_reset: bool

Reset-mode compaction (M4/#9): the continuation gets the preserved prefix + digest only, no verbatim tail — a fresh slate rather than a summarized-then-refilling window. Default false = M2 in-place behavior.

show_context_pct: bool

Include context_used% in the MOIM turn-context block (M4/#9). Default true = M2 behavior; false to avoid inducing context anxiety.

evict_threshold_tokens: u64

Evict a successful tool result larger than this (estimated tokens) to a masked blob, leaving a head preview + read pointer (T4). 0 disables.

Trait Implementations

impl Clone for EngineConfig

fn clone(&self) -> EngineConfig

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for EngineConfig

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

Formats the value using the given formatter.

impl Default for EngineConfig

fn default() -> Self

Returns the “default value” for a type.