Enum Error 

#[non_exhaustive]
pub enum Error {
    Llm {
        provider: String,
        message: String,
    },
    RateLimited {
        provider: String,
        retry_after_ms: u64,
    },
    Tool {
        name: String,
        call_id: Option<String>,
        message: String,
    },
    BadToolArgs {
        name: String,
        message: String,
    },
    ToolRejected {
        name: String,
        reason: String,
    },
    UnknownTool(String),
    PermissionDenied {
        name: String,
        reason: DecisionReason,
    },
    PermissionDeniedLimit {
        name: String,
    },
    ProviderTruncated(String),
    Mcp {
        server: String,
        message: String,
    },
    Config {
        message: String,
    },
    Io(Error),
    Http(Error),
    Json(Error),
    Cancelled,
    Timeout {
        duration_ms: u64,
    },
    Storage {
        message: String,
    },
    NotFound(String),
    SchemaTooNew {
        session_id: String,
        found: u32,
        supported: u32,
    },
    Internal {
        context: String,
        message: String,
    },
}

Variants (Non-exhaustive)

Non-exhaustive enums could have additional variants added in future. Therefore, when matching against variants of non-exhaustive enums, an extra wildcard arm must be added to account for any future variants.

Llm

LLM provider returned an error (HTTP, parse, etc.)

Fields

provider: String

message: String

RateLimited

LLM rate limited — caller should retry after retry_after_ms

Fields

provider: String

retry_after_ms: u64

Tool

Tool execution failure (spawn, timeout, I/O)

call_id links this error back to the tool_call_id of the triggering ToolCall, enabling audit logs and session persistence to correlate the failure with the exact turn that requested the tool.

Fields

name: String

call_id: Option<String>

The tool_call_id from the triggering ToolCall, if available.

message: String

BadToolArgs

Invalid arguments passed to a tool

Fields

name: String

message: String

ToolRejected

Tool rejected execution (policy, constraints, safety)

Fields

name: String

reason: String

UnknownTool(String)

Tool not found in registry

PermissionDenied

Permission denied for a tool call

Fields

name: String

reason: DecisionReason

PermissionDeniedLimit

Auto-classifier denial limit exceeded — agent should stop

Fields

name: String

ProviderTruncated(String)

LLM response truncated by provider

Mcp

MCP protocol/transport error

Fields

server: String

message: String

Config

Configuration error (missing env var, invalid value)

Fields

message: String

Io(Error)

I/O error

Http(Error)

HTTP client error

Json(Error)

JSON serialization/deserialization error

Cancelled

Operation cancelled via CancellationToken.

Timeout

Timeout after a specified duration

Fields

duration_ms: u64

Storage

Storage backend error (I/O, serialization, remote storage, etc.)

Fields

message: String

NotFound(String)

A named resource (team, task, etc.) was requested but does not exist.

SchemaTooNew

Session metadata on disk has a schema_version newer than this build of the binary knows how to interpret. Raised by SessionReader::load_meta when it sees a version greater than the supported maximum — the safe action is to refuse to load the session, not to silently drop fields.

Fields

session_id: String

found: u32

supported: u32

Internal

Internal agent error — unexpected state that does not map to any typed variant. Prefer a specific variant; use Internal only as last resort.

Fields

context: String

message: String

Implementations

impl Error

pub fn is_retryable(&self) -> bool

Returns true if the error is safe to retry (rate limits, timeouts).

pub fn is_transient(&self) -> bool

Returns true if the error is transient (network issues, timeouts). Transient errors may resolve without changing the request.

Trait Implementations

impl Debug for Error

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

Formats the value using the given formatter.

impl Display for Error

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

Formats the value using the given formatter.

impl Error for Error

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 From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.

impl From<Error> for Error

fn from(source: Error) -> Self

Converts to this type from the input type.