Struct McpError 

pub struct McpError { /* private fields */ }

A JSON-RPC error returned to the client.

Implementations

impl McpError

pub fn parse_error() -> Self

-32700: the message is not valid JSON.

pub fn invalid_request(reason: &'static str) -> Self

-32600: the message is not a valid JSON-RPC request.

pub fn method_not_found(method: &str) -> Self

-32601: the method does not exist.

pub fn method_not_found_explained( explanation: impl Into<Cow<'static, str>>, ) -> Self

-32601 with a custom, client-safe explanation.

pub fn invalid_params(message: impl Into<Cow<'static, str>>) -> Self

-32602: the parameters are malformed (including missing _meta).

pub fn unknown_tool(name: &str) -> Self

-32602: the requested tool does not exist.

pub fn request_failed(message: impl Into<Cow<'static, str>>) -> Self

-32602: a well-formed request the handler refused, with a client-safe message (for example a ToolError::user raised while reading a resource or getting a prompt).

pub fn resource_not_found(uri: &str) -> Self

-32602 with data.uri: the resource does not exist (the 2026-07-28 code for resource-not-found).

pub fn unknown_prompt(name: &str) -> Self

-32602: the requested prompt does not exist.

pub fn internal_with_message(message: &'static str) -> Self

-32603 with a client-safe message (no internal details).

pub fn internal() -> Self

-32603: a generic internal error. Details must be logged, not sent.

pub fn insufficient_scope(required: &[String]) -> Self

-32600 with data.requiredScopes: the access token does not grant every scope the handler needs. Over HTTP this is a 403 whose WWW-Authenticate challenge lists the scopes.

pub fn header_mismatch(message: impl Into<Cow<'static, str>>) -> Self

-32020: HTTP headers do not match the request body.

pub fn missing_client_capability(required: &ClientCapabilities) -> Self

-32021: the request needs client capabilities the client did not declare.

pub fn unsupported_protocol_version( requested: &str, supported: &[String], ) -> Self

-32022: the requested protocol version is not supported.

pub fn code(&self) -> i64

The JSON-RPC error code.

pub fn kind(&self) -> ErrorKind

How the error relates to the request.

pub fn message(&self) -> &str

The client-facing message.

pub fn data(&self) -> Option<&Value>

The optional data member.

pub fn into_spec(self) -> Error

Converts into the wire representation.

Trait Implementations

impl Clone for McpError

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for McpError

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

Formats the value using the given formatter.

impl Display for McpError

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

Formats the value using the given formatter.

impl Error for McpError

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 McpError

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for McpError