# spec-no-duplicated-method-params

Each method's `params` list must not contain more than one parameter with the same `name`.

| Open-RPC | Compatibility |
|  --- | --- |
| 1.x | ✅ |


## API design principles

Duplicate parameter names make it unclear which definition applies and can break tooling that indexes parameters by name.

## Configuration

| Option | Type | Description |
|  --- | --- | --- |
| severity | string | Possible values: `off`, `warn`, `error`. Default `error` (in `recommended` ruleset). |



```yaml
rules:
  spec-no-duplicated-method-params: error
```

## Resources

- [Rule source](https://github.com/Redocly/redocly-cli/blob/main/packages/core/src/rules/openrpc/spec-no-duplicated-method-params.ts)