@checkspec/core

Core library for CheckSpec — the test framework for MCP servers.

This package contains the test runner, assertion engine, security scanner, schema-driven input generator, and reporters. It is used internally by @checkspec/cli and @checkspec/sdk. You probably want one of those instead unless you're building custom tooling on top of CheckSpec.

Install

npm install @checkspec/core

What's inside

• MCPRecordingClient — wraps the MCP SDK client, records all request/response pairs
• TestRunner — executes test collections with hooks, retry, parametrize, and concurrency
• SecurityScanner — detects tool poisoning, rug-pull attacks, and prompt injection
• SchemaInputGenerator — generates valid, invalid, edge-case, and fuzz inputs from JSON Schemas
• MCPExpect — chainable assertion API (contains, equals, matches, schema, jsonPath, timing)
• Reporters — Console, HTML, JUnit XML, and JSON output formats
• HookRunner — beforeAll/afterAll/beforeEach/afterEach with capture variables

Subpath exports

import { TestRunner, MCPRecordingClient, SecurityScanner } from "@checkspec/core";
import { collectionSchema, validateCollection } from "@checkspec/core/schema";
import { MCPRecordingClient } from "@checkspec/core/client";
import { TestRunner } from "@checkspec/core/runner";
import { SecurityScanner } from "@checkspec/core/security";
import { SchemaInputGenerator } from "@checkspec/core/generators";
import { HTMLReporter, JUnitReporter } from "@checkspec/core/reporters";

Documentation

Full docs, examples, and the collection format reference are in the main repository.

License

MIT