Enum Error 

#[non_exhaustive]
pub enum Error {
    Protocol(Error),
    Json(Error),
    Verification(VerificationError),
    Cancelled,
    Disconnected,
    Agent(Box<dyn Error + Send + Sync>),
}

Everything that can go wrong while hosting an AG-UI run.

The variant list is #[non_exhaustive]: new emitters and verification rules are expected to add variants without a breaking release.

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.

Protocol(Error)

A core protocol type rejected a value — for example an interrupt outcome carrying no interrupts.

Json(Error)

State, tool arguments or a tool result could not be converted to or from JSON.

Verification(VerificationError)

The emitted event stream broke the protocol’s ordering rules.

Only produced when the verify feature is enabled (it is by default).

Cancelled

The run was cancelled — usually because the client disconnected.

Every emit after cancellation fails with this, so an agent that uses ? on its emits unwinds promptly without any cancellation code of its own.

Disconnected

The consumer dropped the event stream, so there is nowhere left to emit.

Agent(Box<dyn Error + Send + Sync>)

The agent itself failed. Build one with Error::agent.

Implementations

impl Error

pub fn agent<E>(error: E) -> Self

where E: Into<Box<dyn Error + Send + Sync>>,

Wraps an arbitrary agent-side error.

let err = Error::agent("the weather service is down");
assert_eq!(err.code(), "AGENT_ERROR");

pub const fn code(&self) -> &'static str

The machine-readable code placed on the RUN_ERROR event.

pub const fn is_cancelled(&self) -> bool

Whether this error means the run was cancelled rather than that it failed.

pub const fn is_disconnected(&self) -> bool

Whether the consumer has gone away, making further emits pointless.

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<VerificationError> for Error

fn from(source: VerificationError) -> Self

Converts to this type from the input type.