Struct InvalidParamsError 

pub struct InvalidParamsError {
    pub code: i64,
    pub data: Option<Value>,
    pub message: String,
}

Latest MCP Protocol 2026_07_28 A JSON-RPC error indicating that the method parameters are invalid or malformed. In MCP, this error is returned in various contexts when request parameters fail validation:

• Tools: Unknown tool name or invalid tool arguments
• Prompts: Unknown prompt name or missing required arguments
• Pagination: Invalid or expired cursor values
• Logging: Invalid log level
• Elicitation: Server requests an elicitation mode not declared in client capabilities
• Sampling: Missing tool result or tool results mixed with other content

JSON schema

{
 "description": "A JSON-RPC error indicating that the method parameters are invalid or malformed.\n\nIn MCP, this error is returned in various contexts when request parameters fail validation:\n\n- **Tools**: Unknown tool name or invalid tool arguments\n- **Prompts**: Unknown prompt name or missing required arguments\n- **Pagination**: Invalid or expired cursor values\n- **Logging**: Invalid log level\n- **Elicitation**: Server requests an elicitation mode not declared in client capabilities\n- **Sampling**: Missing tool result or tool results mixed with other content",
 "type": "object",
 "required": [
   "code",
   "message"
 ],
 "properties": {
   "code": {
     "description": "The error type that occurred.",
     "type": "integer",
     "const": -32602
   },
   "data": {
     "description": "Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.)."
   },
   "message": {
     "description": "A short description of the error. The message SHOULD be limited to a concise single sentence.",
     "type": "string"
   }
 }
}

Fields

code: i64

The error type that occurred.

data: Option<Value>

Additional information about the error. The value of this member is defined by the sender (e.g. detailed error information, nested errors etc.).

message: String

A short description of the error. The message SHOULD be limited to a concise single sentence.

Trait Implementations

impl Clone for InvalidParamsError

fn clone(&self) -> InvalidParamsError

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for InvalidParamsError

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

Formats the value using the given formatter.

impl<'de> Deserialize<'de> for InvalidParamsError

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Serialize for InvalidParamsError

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.