MCP TypeScript SDK (V2) / @modelcontextprotocol/server / shimsNode

shimsNode

Classes

DefaultJsonSchemaValidator

Defined in: packages/core-internal/src/validators/ajvProvider.ts:81

AJV-backed JSON Schema validator. See @modelcontextprotocol/{client,server}/validators/ajv for the customisation entry point (re-exports Ajv and addFormats from the bundled copy).

Default validates as JSON Schema 2020-12 (SEP-1613). Schemas declaring a different $schema are rejected with a plain Error; pass a pre-configured Ajv instance to validate other dialects. The SDK bundles ajv internally but does not re-export Ajv2020 (its type graph tips downstream declaration bundling — see #2339). To construct a custom 2020-12 instance, add ajv to your own dependencies (matching the SDK's pinned version) and import { Ajv2020 } from 'ajv/dist/2020.js' — new Ajv(...) is the draft-07 class and would silently downgrade dialect.

Examples

Use with default configuration

const validator = new AjvJsonSchemaValidator();

Use with a custom AJV instance

// import { Ajv2020 } from 'ajv/dist/2020.js';
const ajv = new Ajv2020({ strict: false, validateSchema: false, allErrors: true });
const validator = new AjvJsonSchemaValidator(ajv);

Register ajv-formats

// import { Ajv2020 } from 'ajv/dist/2020.js';
const ajv = new Ajv2020({ strict: false, validateSchema: false, allErrors: true });
addFormats(ajv);
const validator = new AjvJsonSchemaValidator(ajv);

Implements

• jsonSchemaValidator

Constructors

Constructor

new DefaultJsonSchemaValidator(ajv?): DefaultJsonSchemaValidator

Defined in: packages/core-internal/src/validators/ajvProvider.ts:96

Parameters

ajv?

AjvLike

Optional pre-configured AJV-compatible instance. When supplied, this instance is used for every schema regardless of its declared $schema (the caller owns dialect choice). When omitted, the provider constructs a single Ajv2020 instance with strict: false, validateFormats: true, validateSchema: false, allErrors: true, and ajv-formats registered — lazily, on the first getValidator call, so constructing the provider (e.g. as the default validator of a Client/Server that never validates a JSON Schema) does not pay the ajv + ajv-formats instantiation cost. The parameter is typed structurally so consumers who don't pass an instance need not have ajv installed.

Returns

DefaultJsonSchemaValidator

Methods

getValidator()

getValidator<T>(schema): JsonSchemaValidator<T>

Defined in: packages/core-internal/src/validators/ajvProvider.ts:106

Create a validator for the given JSON Schema

Type Parameters

T

T

Parameters

schema

JsonSchemaType

Standard JSON Schema object

Returns

JsonSchemaValidator<T>

A validator function that can be called multiple times

Implementation of

jsonSchemaValidator.getValidator

Variables

process

process: NodeJS.Process

Defined in: node_modules/.pnpm/@types+node@24.12.0/node_modules/@types/node/globals.d.ts:3