Enum McpError 

pub enum McpError {
    Integration(IntegrationError),
    Protocol(ProtocolError),
    NotConnected,
    CapabilityNegotiationFailed {
        reason: String,
    },
    UnsupportedCapability {
        capability: String,
    },
    ResourceNotFound {
        uri: String,
    },
    ToolNotFound {
        name: String,
    },
    ToolExecutionFailed {
        name: String,
        reason: String,
    },
    PromptNotFound {
        name: String,
    },
    InvalidPromptArguments {
        prompt: String,
        reason: String,
    },
    SubscriptionFailed {
        uri: String,
        reason: String,
    },
    ServerError {
        message: String,
    },
    Timeout {
        seconds: u64,
    },
    InvalidResponse {
        reason: String,
    },
    AlreadyConnected,
    InvalidState {
        state: String,
    },
    Custom {
        message: String,
    },
}

MCP-specific error types

Variants

Integration(IntegrationError)

Integration layer error (JSON-RPC, transport)

Protocol(ProtocolError)

Protocol-specific error (validation, format)

NotConnected

Connection not established or lost

CapabilityNegotiationFailed

Capability negotiation failed

Fields

reason: String

UnsupportedCapability

Server does not support requested capability

Fields

capability: String

ResourceNotFound

Resource not found

Fields

uri: String

ToolNotFound

Tool not found

Fields

name: String

ToolExecutionFailed

Tool execution failed

Fields

name: String

reason: String

PromptNotFound

Prompt not found

Fields

name: String

InvalidPromptArguments

Invalid prompt arguments

Fields

prompt: String

reason: String

SubscriptionFailed

Subscription failed

Fields

uri: String

reason: String

ServerError

Server error response

Fields

message: String

Timeout

Timeout waiting for response

Fields

seconds: u64

InvalidResponse

Invalid server response format

Fields

reason: String

AlreadyConnected

Connection already established

InvalidState

Operation not allowed in current state

Fields

state: String

Custom

Custom error for user-defined errors

Fields

message: String

Implementations

impl McpError

pub fn custom(message: impl Into<String>) -> Self

Create a new custom error

pub fn capability_negotiation_failed(reason: impl Into<String>) -> Self

Create a capability negotiation failed error

pub fn unsupported_capability(capability: impl Into<String>) -> Self

Create an unsupported capability error

pub fn resource_not_found(uri: impl Into<String>) -> Self

Create a resource not found error

pub fn tool_not_found(name: impl Into<String>) -> Self

Create a tool not found error

pub fn tool_execution_failed( name: impl Into<String>, reason: impl Into<String>, ) -> Self

Create a tool execution failed error

pub fn prompt_not_found(name: impl Into<String>) -> Self

Create a prompt not found error

pub fn invalid_response(reason: impl Into<String>) -> Self

Create an invalid response error

pub fn invalid_request(details: impl Into<String>) -> Self

Create an invalid request error

pub fn method_not_found(method: impl Into<String>) -> Self

Create a method not found error

pub fn server_error(message: impl Into<String>) -> Self

Create a server error

pub fn already_connected() -> Self

Create an already connected error

pub fn invalid_state(state: impl Into<String>) -> Self

Create an invalid state error

pub fn internal_error(message: impl Into<String>) -> Self

Create an internal error (alias for server_error)

pub fn invalid_prompt_arguments( prompt: impl Into<String>, reason: impl Into<String>, ) -> Self

Create an invalid prompt arguments error

pub fn subscription_failed( uri: impl Into<String>, reason: impl Into<String>, ) -> Self

Create a subscription failed error

pub fn timeout(seconds: u64) -> Self

Create a timeout error

pub fn is_recoverable(&self) -> bool

Check if this error is recoverable (can retry)

pub fn is_connection_error(&self) -> bool

Check if this error indicates a connection problem

pub fn category(&self) -> &'static str

Get the error category for telemetry/logging

Trait Implementations

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, __formatter: &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 From<IntegrationError> for McpError

fn from(source: IntegrationError) -> Self

Converts to this type from the input type.

impl From<ProtocolError> for McpError

fn from(source: ProtocolError) -> Self

Converts to this type from the input type.

impl From<TransportError> for McpError

fn from(err: TransportError) -> Self

Converts to this type from the input type.

impl From<TransportError> for McpError

fn from(err: TransportError) -> Self

Converts to this type from the input type.