Enum AgentError 

pub enum AgentError {
    Provider(ProviderError),
    Config(String),
    Validation(String),
    PermissionDenied(String),
    ToolNotFound(String),
    ToolExecution {
        tool: String,
        message: String,
    },
    MaxIterations(usize),
    ProviderRetriesExhausted {
        attempts: usize,
        last_error: String,
    },
    SessionBusy,
    Cancelled,
}

All error conditions surfaced by the agent runtime.

Variants

Provider(ProviderError)

The model provider (HTTP transport, API contract, deserialisation, …) failed.

Config(String)

A misconfigured session or backend (missing env var, unwritable storage dir, …).

Validation(String)

Tool input failed schema/business-rule validation before execution.

PermissionDenied(String)

The permission engine or a tool refused to execute the call.

ToolNotFound(String)

The assistant requested a tool that isn’t in the registry.

ToolExecution

A tool ran but reported a runtime failure.

Fields

tool: String

message: String

MaxIterations(usize)

The turn loop exceeded AgentConfig::max_iterations.

ProviderRetriesExhausted

Provider retries exhausted — every attempt failed.

Fields

attempts: usize

last_error: String

SessionBusy

Another turn is already running for this session.

Cancelled

The turn was cancelled via CancellationState.

Implementations

impl AgentError

pub fn is_retryable(&self) -> bool

Whether the error is transient and worth retrying.

Network errors and server-side 429/5xx responses are retryable; configuration errors, validation failures, and permission denials are not.

pub fn is_context_too_long(&self) -> bool

Whether the error indicates the context window was exceeded.

HTTP 400 with a message about context/token length means the request was too large for the model. This is NOT retryable in the normal sense (repeating the same request will fail), but it IS recoverable via compaction: summarise history, then retry with fewer tokens.

Trait Implementations

impl Clone for AgentError

fn clone(&self) -> AgentError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for AgentError

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

Formats the value using the given formatter.

impl Display for AgentError

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

Formats the value using the given formatter.

impl Error for AgentError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl Serialize for AgentError

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

where __S: Serializer,

Serialize this value into the given Serde serializer.