What causes "key requires argument (e.g. Enter, Tab, Escape)" in Mintplex-Labs/anything-llm?

Pass a key name: `node cdp-input.js key Enter`.

Mintplex-Labs/anything-llm · error · Error

key requires <key> argument (e.g. Enter, Tab, Escape)

Error message

key requires <key> argument (e.g. Enter, Tab, Escape)

What it means

Thrown by the 'key' branch of cdp-input.js when process.argv[3] is falsy. The key action dispatches a single keyDown/keyUp pair using either a definition from the specialKeys map (Enter, Tab, Escape, arrows, etc.) or a synthesized {Key<UPPER>} definition, so a key name is mandatory.

Source

Thrown at open-computer/services/interface-service/utils/cdp-input.js:175

          key: char,
          code: charToCode(char),
          unmodifiedText: char,
        }, sessionId);

        await cdpSend(ws, "Input.dispatchKeyEvent", {
          type: "keyUp",
          key: char,
          code: charToCode(char),
        }, sessionId);

        await sleep(keystrokeDelay());
      }

      process.stdout.write(`typed ${text.length} chars`);

    } else if (action === "key") {
      const key = process.argv[3];
      if (!key) throw new Error("key requires <key> argument (e.g. Enter, Tab, Escape)");

      const keyDef = specialKeys[key] || { key, code: `Key${key.toUpperCase()}` };

      await cdpSend(ws, "Input.dispatchKeyEvent", {
        type: "keyDown",
        key: keyDef.key,
        code: keyDef.code,
        windowsVirtualKeyCode: keyDef.keyCode || 0,
        nativeVirtualKeyCode: keyDef.keyCode || 0,
      }, sessionId);
      await sleep(50);

      await cdpSend(ws, "Input.dispatchKeyEvent", {
        type: "keyUp",
        key: keyDef.key,
        code: keyDef.code,
        windowsVirtualKeyCode: keyDef.keyCode || 0,
        nativeVirtualKeyCode: keyDef.keyCode || 0,

View on GitHub (pinned to 526360e320)

Solutions

Pass a key name: `node cdp-input.js key Enter`.
For special keys use the exact map names: Enter, Tab, Escape, Backspace, Delete, ArrowUp/Down/Left/Right, Home, End, PageUp, PageDown, Space.
In the caller, assert the key string is non-empty before spawning.

Example fix

// before
spawn('node', ['cdp-input.js', 'key']);
// after
spawn('node', ['cdp-input.js', 'key', 'Enter']);

Defensive patterns

Strategy: validation

Validate before calling

if (typeof key !== 'string' || key.length === 0) {
  throw new Error('A non-empty key name is required for key action');
}

Prevention

Use exact specialKeys names (Enter, Tab, Escape, ArrowUp, etc.).
Assert key is non-empty before spawning.
Document the key action's argv layout: key <key> [target_url].

When it happens

Trigger: Running `node cdp-input.js key` with no key argument. The key must be a recognized special-key name or a single letter; an empty value cannot be mapped to a code.

Common situations: Caller passed an undefined key variable; the key name used a different casing than the specialKeys map (e.g. 'enter' vs 'Enter') — though that would not throw this error, it would synthesize a wrong code.

Related errors

AI-assisted analysis of Mintplex-Labs/anything-llm@526360e320 (2026-08-13). Data as JSON: /api/errors/e1a32eae646143c1. Report an issue: GitHub.