Struct CircuitBreaker 

pub struct CircuitBreaker { /* private fields */ }

Per-tool circuit breaker that tracks failure state independently for each tool. This prevents one misbehaving tool from disabling all tools in the system.

Uses parking_lot::RwLock for better concurrent access:

• Read operations (allow_request, state checks) can proceed in parallel
• Write operations (record_success/failure) acquire exclusive access
• parking_lot is more efficient for short critical sections than std::Mutex

Implementations

impl CircuitBreaker

pub fn new(config: CircuitBreakerConfig) -> Self

pub fn with_metrics( config: CircuitBreakerConfig, metrics: Arc<MetricsCollector>, ) -> Self

pub fn allow_request_for_tool(&self, tool_name: &str) -> bool

Check if a request for a specific tool is allowed to proceed. Returns true if allowed, false if the circuit is open for this tool.

Uses optimistic read-first approach:

1. Try read lock first (allows concurrent reads)
2. Only upgrade to write lock if state transition is needed

pub fn remaining_backoff(&self, tool_name: &str) -> Option<Duration>

Get remaining backoff time for a tool (if Open)

pub fn record_success_for_tool(&self, tool_name: &str)

Record success for a specific tool

State transitions on success:

• HalfOpen -> Closed (probe succeeded)
• Closed -> Closed (reset failure count)
• Open -> Closed (forced recovery, e.g., manual reset)

pub fn record_failure_category_for_tool( &self, tool_name: &str, category: ErrorCategory, )

Record failure for a specific tool. Non-retryable validation, policy, and permission failures are ignored.

State transitions on failure:

• Closed -> Open (when threshold reached)
• HalfOpen -> Open (probe failed, increase backoff)
• Open -> Open (no change, just update timestamp)

pub fn record_failure_for_tool(&self, tool_name: &str, is_argument_error: bool)

Convenience wrapper that maps a boolean argument error flag to the appropriate ErrorCategory.

pub fn state_for_tool(&self, tool_name: &str) -> CircuitState

Get the circuit state for a specific tool

pub fn reset_tool(&self, tool_name: &str)

Reset the circuit breaker state for a specific tool

pub fn reset_all(&self)

Reset all tool circuit breaker states

pub fn get_open_circuits(&self) -> Vec<String>

Get list of tools with currently OPEN circuits

pub fn get_diagnostics(&self, tool_name: &str) -> ToolCircuitDiagnostics

Get diagnostic information for a specific tool

pub fn get_all_diagnostics(&self) -> Vec<ToolCircuitDiagnostics>

Get diagnostics for all tools

pub fn snapshot(&self) -> CircuitBreakerSnapshot

Get a full snapshot of circuit breaker state under a single read lock.

pub fn should_pause_for_recovery(&self, max_open_circuits: usize) -> bool

Check if recovery pause should be triggered based on open circuit count

pub fn open_circuit_count(&self) -> usize

Get count of currently open circuits

Trait Implementations

impl Clone for CircuitBreaker

fn clone(&self) -> CircuitBreaker

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for CircuitBreaker

fn default() -> Self

Returns the “default value” for a type.