# Test your MCP server with the eval command

The `eval` command enables rapid testing of your MCP server directly from the command line, without firing up an MCP client like Cursor or Claude Desktop. Use it to verify tool functionality, debug issues, and iterate quickly during development.

## Enable the eval command

The `eval` command is not generated by default. To include it, set the `evalProvider` flag in your `gen.yaml` configuration:

```yaml filename="gen.yaml"
targets:
  mcp-typescript:
    evalProvider: anthropic
```

Set `evalProvider` to one of the following supported providers:

| Provider | Value |
| --- | --- |
| Anthropic | `anthropic` |
| OpenAI | `openai` |

<Callout type="info">
  The eval command uses the [Vercel AI SDK](https://sdk.vercel.ai/) internally, so adding support for additional providers is straightforward. If you'd like support for a provider not listed here, [reach out to us](https://speakeasy.com/contact).
</Callout>

After setting the `evalProvider` flag, regenerate your MCP server to include the `eval` command.

## Usage

Run the `eval` command with a natural language prompt describing what you want to test:

```bash
./bin/mcp-server.js eval \
  --username "{your-username}" \
  --password "{your-password}" \
  --anthropic-api-key "{your-anthropic-api-key}" \
  "give me a list of the names of all the connections in my account"
```

The command sends your prompt to the configured AI provider, which determines the appropriate MCP tools to call and returns the result.

### Flags

The `eval` command accepts the following flags depending on your API's authentication requirements and the configured provider:

- **`--username`**: Username for API authentication (if required by your API).
- **`--password`**: Password for API authentication (if required by your API).
- **`--anthropic-api-key`**: Your Anthropic API key (required when using the `anthropic` provider).
- **`--openai-api-key`**: Your OpenAI API key (required when using the `openai` provider).

<Callout type="info">
  The authentication flags vary based on your API's security scheme. The `eval` command inherits the same authentication options as the `start` command.
</Callout>

## Example workflows

### Verify tool discovery

Confirm that your MCP server exposes the expected tools:

```bash
./bin/mcp-server.js eval \
  --anthropic-api-key "{your-anthropic-api-key}" \
  "what tools are available?"
```

### Test a specific operation

Verify that a specific API operation works correctly:

```bash
./bin/mcp-server.js eval \
  --username "{your-username}" \
  --password "{your-password}" \
  --anthropic-api-key "{your-anthropic-api-key}" \
  "create a new booking from station 1 to station 5 for tomorrow"
```

### Debug error handling

Test how your server handles invalid inputs:

```bash
./bin/mcp-server.js eval \
  --username "{your-username}" \
  --password "{your-password}" \
  --anthropic-api-key "{your-anthropic-api-key}" \
  "delete a booking with ID that doesn't exist"
```