---
title: "Point links at a local playground"
description: "Generate monedula-sim-link links for a playground dev server on your machine instead of monedula.dev, with --base-url on connect, demo and mcp."
url: https://monedula.dev/flock/docs/sim-link/how-to/point-at-a-local-playground/
---
Every link `monedula-sim-link` prints starts with the address of the public playground. `--base-url` replaces it with the address of a playground you run yourself.

## Before you start

- A playground dev server that you can open in a browser. The examples use `http://localhost:4321/kafka-simulator/playground`.
- `monedula-sim-link` installed, as described in the [install section](/flock/docs/sim-link/#install).

## Steps

### 1. Pass `--base-url` to the command

`--base-url` takes the full address of the playground page, in place of the default `https://monedula.dev/kafka-simulator/playground`:

```bash
monedula-sim-link connect --brokers localhost:9092 \
  --base-url http://localhost:4321/kafka-simulator/playground
```

The flag works the same way on `demo`, which is a quick way to try your playground without a cluster:

```bash
monedula-sim-link demo --base-url http://localhost:4321/kafka-simulator/playground
```

### 2. Or set it for the MCP server

For an AI agent, add `--base-url` to the arguments of the server in your client configuration, so that every link the agent produces points at your playground:

```json
{
  "mcpServers": {
    "monedula-sim-link": {
      "command": "monedula-sim-link",
      "args": ["mcp", "--base-url", "http://localhost:4321/kafka-simulator/playground"]
    }
  }
}
```

[Use the MCP server](/flock/docs/sim-link/how-to/use-the-mcp-server/) shows where this configuration goes.

## Check it worked

The printed link starts with the address you gave, followed by `?scenario=free`:

```text
http://localhost:4321/kafka-simulator/playground?scenario=free&actions=...&size=...
```

Open it: your local playground loads the session. Only the part before the question mark changes: the same snapshot gives the same query string whatever the base URL is.

## Related

- The [`connect` command reference](/flock/docs/sim-link/reference/cli/connect/) lists `--base-url` and its default; `demo` and `mcp` take the same flag.
- The [playground URL format](/flock/docs/kafka-simulator/reference/url-format/) specifies the parameters after the question mark.