astral-sh/ruff · error

InvalidParams

InvalidParams

Error message

Invalid command `{name}`

What it means

The Ruff language server accepts exactly four workspace/executeCommand command IDs: ruff.applyAutofix, ruff.applyFormat, ruff.applyOrganizeImports, and ruff.printDebugInformation. The command string from the request is parsed via FromStr; anything else fails to parse and the request is rejected with an InvalidParams error.

Solutions

1. Use one of the exact IDs: ruff.applyAutofix, ruff.applyFormat, ruff.applyOrganizeImports, ruff.printDebugInformation
2. Update the Ruff extension and server together so command names match the running version
3. Check the server's tracing log to see the raw command string it received
4. Prefer LSP native requests (textDocument/formatting, codeAction source.fixAll) over executeCommand where available

Example fix

// before
await connection.sendRequest('workspace/executeCommand', { command: 'ruff.applyFix', arguments: [{ uri: docUri }] });
// Error: Invalid command `ruff.applyFix`

// after
await connection.sendRequest('workspace/executeCommand', { command: 'ruff.applyAutofix', arguments: [{ uri: docUri }] });

// Whitelist the commands this server version supports before invoking
const SUPPORTED = new Set([
  'ruff.applyAutofix',
  'ruff.applyFormat',
  'ruff.applyOrganizeImports',
  'ruff.printDebugInformation',
]);
if (!SUPPORTED.has(command)) throw new Error(`unsupported command: ${command}`);
await conn.sendRequest('workspace/executeCommand', { command, arguments });

function isSupportedRuffCommand(cmd: string): cmd is
  | 'ruff.applyAutofix' | 'ruff.applyFormat'
  | 'ruff.applyOrganizeImports' | 'ruff.printDebugInformation' {
  return cmd === 'ruff.applyAutofix' || cmd === 'ruff.applyFormat'
    || cmd === 'ruff.applyOrganizeImports' || cmd === 'ruff.printDebugInformation';
}

When it happens

Trigger: Typos like `ruff.applyFix` or `ruff.autofix`; invoking commands from a newer/older extension than the running server; clients guessing command names instead of using the ones the extension advertises; wrappers forwarding commands meant for another server.

Common situations: Custom editor integrations hardcoding command IDs across Ruff versions; mismatched extension/server versions after an upgrade; copy-pasted sample code using renamed commands.

Related errors

• Failed to send notification
• Failed to send response for request
• InternalError
• InternalError
• InternalError

AI-assisted analysis of astral-sh/ruff@d1087a4b9e (2026-08-20). Data as JSON: /api/errors/1ffb4e3e14108265. Report an issue: GitHub.

Appendix: source

Thrown at crates/ruff_server/src/server.rs:368

        [
            SupportedCommand::Format,
            SupportedCommand::FixAll,
            SupportedCommand::OrganizeImports,
            SupportedCommand::Debug,
        ]
    }
}

impl FromStr for SupportedCommand {
    type Err = anyhow::Error;

    fn from_str(name: &str) -> anyhow::Result<Self, Self::Err> {
        Ok(match name {
            "ruff.applyAutofix" => Self::FixAll,
            "ruff.applyFormat" => Self::Format,
            "ruff.applyOrganizeImports" => Self::OrganizeImports,
            "ruff.printDebugInformation" => Self::Debug,
            _ => return Err(anyhow::anyhow!("Invalid command `{name}`")),
        })
    }
}

type PanicHook = Box<dyn Fn(&PanicHookInfo<'_>) + 'static + Sync + Send>;

struct ServerPanicHookHandler {
    hook: Option<PanicHook>,
    // Hold on to the strong reference for as long as the panic hook is set.
    _client: Arc<Client>,
}

impl ServerPanicHookHandler {
    fn new(client: Client) -> Self {
        let hook = std::panic::take_hook();
        let client = Arc::new(client);

        // Use a weak reference to the client because it must be dropped when exiting or the

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