Struct CoercionError 

pub struct CoercionError {
    pub message: String,
    pub parameter_path: Option<String>,
    pub expected_type: Option<String>,
    pub received_value: Option<Value>,
    pub hint: Option<String>,
}

Structured error type for coercion failures.

Provides rich error information to help AI agents understand what went wrong and how to fix it.

Fields

message: String

Human-readable error message

parameter_path: Option<String>

Path to the parameter that failed (e.g., “session_id”, “updates[0].interaction_type”)

expected_type: Option<String>

Expected type description (e.g., “UUID string”, “one of: qa, decision_made, …”)

received_value: Option<Value>

The actual value that was received

hint: Option<String>

Actionable hint for fixing the error

Implementations

impl CoercionError

pub fn new( message: &str, source_error: impl Error, received_value: Option<Value>, ) -> Self

Create a new coercion error.

pub fn with_parameter_path(self, path: String) -> Self

Set the parameter path for this error.

pub fn with_expected_type(self, type_desc: &str) -> Self

Set the expected type description for this error.

pub fn with_hint(self, hint: &str) -> Self

Set a hint for fixing this error.

pub fn to_mcp_error(&self) -> ErrorData

Convert this error to an MCP error response.

Creates a structured JSON error that agents can parse and understand. Includes automatically generated recovery suggestions.

Trait Implementations

impl Clone for CoercionError

fn clone(&self) -> CoercionError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for CoercionError

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

Formats the value using the given formatter.

impl Display for CoercionError

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

Formats the value using the given formatter.

impl Error for CoercionError

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.