Setup Kerno MCP

This guide explains how to attach Cursor or Claude Code to Kerno’s local MCP endpoint after the Kerno IDE extension has started the Kerno agent for your project.

This guide explains how to attach Cursor or Claude Code to Kerno’s local MCP endpoint after the Kerno IDE extension has started the Kerno agent for your project.

What you get

Your assistant can use Kerno’s MCP tools from the IDE—for example workspace checks, listing applications and endpoints, starting environments, capturing baselines, and running validation—without leaving your editor.

Prerequisites

• Kerno IDE extension installed and your repository open in the IDE.

• The local Kerno agent is running for that workspace (wait until Kerno has finished its usual startup for the project).

• MCP is exposed by default on port 8086 at:

  http://127.0.0.1:8086/mcp

  Use this address only on the same computer where the IDE and agent run.

Important details

• Workspace path: When a tool asks for a workspace path, use the absolute path of the project folder Kerno is using. Paths that do not match that project are rejected.

• Long operations: Some tools start work in the background and return a job id quickly. Use the job tools Kerno exposes to check status or logs; avoid asking the model to poll every few seconds. Very long steps (for example environment builds) can take many minutes.

Cursor

1. Open Cursor’s MCP configuration (from Settings, or the MCP section documented in Cursor’s MCP help).

2. Add a server that points at Kerno’s endpoint.

Example:

{
  "mcpServers": {
    "kerno": {
      "url": "http://127.0.0.1:8086/mcp"
    }
  }
}

1. Save the configuration. If Kerno tools do not show up, reload MCP or restart Cursor.

Tool names in the UI may be prefixed by Cursor; they still correspond to Kerno’s tools.

Claude Code

Use the HTTP transport so Claude Code talks to the same local URL.

Project scope (configuration can live with the repository):

claude mcp add --transport http kerno --scope project http://127.0.0.1:8086/mcp

Local scope (for the current machine only):

claude mcp add --transport http kerno --scope local http://127.0.0.1:8086/mcp

If you edit JSON instead of using the CLI, use the same URL and the HTTP type your Claude Code version expects—for example:

{
  "mcpServers": {
    "kerno": {
      "type": "http",
      "url": "http://127.0.0.1:8086/mcp"
    }
  }
}

See Connect Claude Code to tools via MCP for scopes, headers, and troubleshooting.

Restart or reopen Claude Code in the project if the server does not appear.

If the connection fails

• Confirm the Kerno extension has started and your project is the active workspace.

• Confirm nothing else is blocking localhost access on port 8086.

• Confirm the URL is exactly http://127.0.0.1:8086/mcp (including /mcp).

• If your team uses a custom MCP port, replace 8086 with the value shown in Kerno’s settings or status in the IDE.

Further reading

• Kerno documentation