Use Insomnia MCP clients to test aggregated MCP tools

Uses: Insomnia AI Gateway deck

Prerequisites

Insomnia

Download and install Insomnia.

decK v1.43+

decK is a CLI tool for managing Kong Gateway declaratively with state files. To complete this tutorial, install decK version 1.43 or later.

This guide uses deck gateway apply, which directly applies entity configuration to your Gateway instance. We recommend upgrading your decK installation to take advantage of this tool.

You can check your current decK version with deck version.

Aggregated MCP server

Before testing with Insomnia, complete the Aggregate MCP tools from multiple AI MCP Proxy plugins guide.
That guide produces:

Multiple conversion-only AI MCP Proxy plugin instances that each expose MCP tools
One listener-mode AI MCP Proxy plugin aggregating those tools by tag
A public listener endpoint:
```
http://localhost:8000/mcp-listener
```
Copied!

Network access

Ensure your local machine can reach the listener endpoint produced during aggregation.

Test connectivity:

curl http://localhost:8000/mcp-listener

Copied!

Use Insomnia to connect to an MCP server exposed through the AI MCP Proxy plugin in listener mode.

This listener server aggregates MCP tools from multiple upstream APIs, enabling you to validate end-to-end behaviour using Insomnia’s Params, Headers, Events, and Console panels.

After completing the aggregation workflow described in Aggregate MCP tools from multiple AI MCP Proxy plugins and exposing an autogenerated or aggregated MCP server, follow this guide to test and validate its MCP tools using Insomnia’s MCP Clients.

Create an MCP client

Open Insomnia.
In the sidebar, click MCP Clients.
Click New MCP Client.
In the Name field, enter a name: Aggregated MCP Tools
In the MCP Server URL field, enter your listener URL: http://localhost:8000/mcp-listener
Click Connect.

Insomnia connects to the MCP server and discovers all of the aggregated tools.

Validate tools

In the sidebar, locate the Tools drop-down section.
Review the list of available tools.

If any tools are missing:

Confirm that all conversion-only plugins use the same tags[] value.

Confirm that the listener-mode plugin’s server.tag matches that value.

Confirm that the listener Route is active and reachable.

Test tools

Use Insomnia’s testing panels to validate MCP tool behaviour:

In Tools, click any tool.
In the request pane, click the Params tab.
Enter the required parameter value.
Click Call Tool.
In the response pane, click the Console tab.

A successful response confirms that your aggregated MCP configuration is working correctly.