Documentation Index
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Overview
Validation errors are thrown when input parameters fail schema validation, when tool output doesn’t match the expected schema, when an HTTP method doesn’t match, or when a required prompt argument is missing.
Error Reference
Thrown when input parameters fail Zod schema validation. This is a public error — validation details are included in the response to help clients fix their requests.
| Property | Type | Value |
|---|
code | string | INVALID_INPUT |
statusCode | number | 400 |
isPublic | boolean | true |
validationErrors | any | Zod validation error details |
new InvalidInputError(message?: string, validationErrors?: any)
import { InvalidInputError } from '@frontmcp/sdk';
throw new InvalidInputError('Validation failed', {
field: 'email',
reason: 'Invalid format',
});
InvalidOutputError
Thrown when a tool’s output does not match the declared output schema. This is an internal error — schema details are not exposed to clients.
| Property | Type | Value |
|---|
code | string | INVALID_OUTPUT |
statusCode | number | 500 |
isPublic | boolean | false |
new InvalidOutputError(errorId?: string)
errorId (e.g., a request ID) is provided, it is included in the public message for correlation. Otherwise, a generic message is returned.
Example:
import { InvalidOutputError } from '@frontmcp/sdk';
throw new InvalidOutputError('req_abc123');
// Client sees: "Output validation failed. Please contact support with error ID: req_abc123"
InvalidMethodError
Thrown when a request uses the wrong HTTP method (e.g., GET instead of POST).
| Property | Type | Value |
|---|
code | string | INVALID_METHOD |
statusCode | number | 400 |
isPublic | boolean | true |
new InvalidMethodError(method: string, expected: string)
import { InvalidMethodError } from '@frontmcp/sdk';
throw new InvalidMethodError('GET', 'POST');
// "Invalid method "GET". Expected "POST""
MissingPromptArgumentError
Thrown when a required prompt argument is not provided by the caller.
| Property | Type | Value |
|---|
code | string | MISSING_PROMPT_ARGUMENT |
statusCode | number | 400 |
isPublic | boolean | true |
new MissingPromptArgumentError(argName: string)
import { MissingPromptArgumentError } from '@frontmcp/sdk';
throw new MissingPromptArgumentError('topic');
// "Missing required argument: topic"
