"Allowing an AI agent to ask user questions during a task" matching MCP connectors:

Free platform to test MCP clients without installing anything. Create mock tools with dynamic templates, configurable delays, conditions (if/then), and response sequences. Supports JSON-RPC 2.0 over Streamable HTTP. Built-in text_echo and json_echo tools. Rate-limited tiers: anonymous (5 calls/min, 1 mock tool), registered (10 calls/min, 4 mock tools), premium (60 calls/min, unlimited). Zero setup — no install, no registration required. More info: https://www.testmcp.dev

Point Gecko at an OpenAPI spec; get first-call-correct, auth-hidden agent tools.

Deterministic JSON checks with signed evidence and x402-paid execution

Check an MCP endpoint resolves: liveness, live tool list, schema drift. Free.

Anonymous webhook capture, inspection, waiting, and response configuration for AI agents.

Instant no-signup webhook & HTTP-request inspector for testing webhooks and agent tool-callbacks.

Verify x402 endpoints before payment or publish service profiles for agent discovery.

Deterministic validation for AI-generated artifacts: JSON Schema, OpenAPI response, SQL syntax.

Debug webhooks from your AI agent: inspect and replay captured webhooks on localhost.

API governance for AI agents. Detects breaking changes, scores blast radius, blocks unsafe calls.

End-to-end API testing — generate and run tests from OpenAPI, curl, Postman, or real user traffic.

MCP server that delivers up-to-date Bitrix24 REST API documentation.

An MCP server that provides tools to validate an email address using Dilli Email Validation API.

Swagger Petstore API (v1.0.27) as MCP for testing and prototyping powered by the HAPI MCP server

Public benchmark where agents submit Q&A answers and get scored on a leaderboard.

A webhook inbox for agents: one call returns a live URL. Mock, verify, inspect and replay.

Manage your Nahook webhooks from your AI client — inspect deliveries, retry failures, and manage endpoints. Connects over OAuth, no API keys

Search, document and execute authenticated API calls across 700+ apps via one MCP server

MCP server for AI access to SmartBear tools, including BugSnag, Reflect, Swagger, PactFlow, QTM4J.

MCP server for AI access to Swagger by SmartBear.