Enum HarnessError 

#[non_exhaustive]
pub enum HarnessError {
    CapabilityNotSupported {
        primitive: String,
    },
    StaleTarget {
        detail: String,
    },
    Transport {
        detail: String,
    },
    Protocol {
        detail: String,
    },
    Harness {
        detail: String,
    },
}

The neutral error taxonomy for the harness-integration seam.

Every arm is harness-neutral. Self::CapabilityNotSupported is the first-class outcome an observability-only harness returns from crate::AgentSession::intervene for any command — it is a legitimate, gated rejection, not an internal failure.

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.

CapabilityNotSupported

The requested intervention primitive is not in the harness’s advertised capability set.

This is the first-class rejection an observability-only harness (empty capability set) returns for every command, and the rejection any harness returns for a primitive it did not advertise. It is a normal, expected outcome of capability gating — not a fault.

Fields

primitive: String

A neutral label naming the unsupported primitive (e.g. "pause_resume").

StaleTarget

The command targets a stale or unknown activity attempt and is a no-op.

A command addressed to a superseded attempt (a later attempt is now live) or to a session that has already reached its terminal result is dropped without effect.

Fields

detail: String

Human-readable detail describing why the target is stale.

Transport

The underlying transport failed (spawn/connect failure, broken pipe, EOF, I/O error).

Neutral: it describes that the transport failed and carries the detail, never which transport. An adapter maps its own I/O failures here.

Fields

detail: String

Human-readable description of the transport failure.

Protocol

A message was received that violates the wire protocol contract.

Malformed framing, an undecodable envelope, a response that correlates to no outstanding request, or a terminal result delivered on the wrong message kind. This signals a bug in the peer or the adapter, distinct from an ordinary transport outage.

Fields

detail: String

Human-readable description of the protocol violation.

Harness

The harness reported an application-level failure while running the agent.

The agent ran but ended in failure (a non-success exit, an error result, a rejected run). Distinct from Self::Transport (the channel broke) and Self::Protocol (a malformed message): here the channel and framing were sound and the harness reported failure.

Fields

detail: String

Human-readable description of the reported failure.

Implementations

impl HarnessError

pub fn capability_not_supported(primitive: impl Into<String>) -> Self

Builds a Self::CapabilityNotSupported naming the unsupported primitive.

pub fn stale_target(detail: impl Into<String>) -> Self

Builds a Self::StaleTarget with a detail message.

pub fn transport(detail: impl Into<String>) -> Self

Builds a Self::Transport with a detail message.

pub fn protocol(detail: impl Into<String>) -> Self

Builds a Self::Protocol with a detail message.

pub fn harness(detail: impl Into<String>) -> Self

Builds a Self::Harness with a detail message.

Trait Implementations

impl Clone for HarnessError

fn clone(&self) -> HarnessError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for HarnessError

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

Formats the value using the given formatter.

impl Display for HarnessError

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

Formats the value using the given formatter.

impl Eq for HarnessError

impl Error for HarnessError

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 PartialEq for HarnessError

fn eq(&self, other: &HarnessError) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for HarnessError