MCP Server Tester for Connection and Tool Debugging

Test MCP server connections, JSON-RPC requests, and tool responses so you can debug MCP setups before they block agent work.

Quick orientation

When to use this tool

Use this MCP tester when the server connection exists on paper but you need proof that requests, tools, and responses are actually behaving the way your agent expects.

1
When bringing a new MCP server online
2
When a tool call fails and you are not sure whether the issue is transport or payload
3
When validating a server before sharing it with a team

Server URL

API Key (optional)

Method

Params (JSON)

Response

Response will appear here

Common MCP reality check

A server can be reachable and still be unusable if the method names, payload shape, or tool exposure are off. This tool is meant to catch that gap before the bigger workflow inherits it.

Check raw JSON-RPC calls before layering agent logic on top
Confirm tool discovery and responses outside the full app
Narrow down whether the fault is config, transport, or tool implementation

Transport vs tool layer

How to narrow down an MCP failure faster

The trick is separating connection problems from method and payload problems early. Otherwise every failure starts to look the same.

Run initialize and ping first when you are not even sure the transport layer is healthy.

If tools/list works but tools/call fails, the problem is often params shape, not connectivity.

Treat resource and prompt endpoints as separate surfaces. One passing does not prove the rest are fine.

Save one real successful call so you can compare later regressions against it instead of guessing.

Related tools

Keep the decision moving

Most tool decisions connect to a second task right away. These are the next pages worth opening if you want fewer surprises later.

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API Tester

Probe OpenClaw and related APIs quickly so you can debug payloads, auth, and response shape in one place.

📨

A2A Sender

Test agent-to-agent messages before you wire them into a real orchestration flow.

✅

JSON Validator

Catch malformed JSON and schema mismatches before they break an automation, integration, or deploy.

Learn next

Turn the estimate into a better setup

If the tool solved the immediate question, this is the next place to go for the broader workflow, tradeoffs, and implementation detail.

Read the guide to MCP servers

FAQ

Can I use this before writing any custom MCP client code?

Yes. That is one of the best uses for it. Validate the server behavior first, then build the client around what actually works.

Does this replace full end-to-end MCP testing?

No. It helps you prove the server layer, which makes later end-to-end testing much easier and cleaner.