Yeachan-Heo/oh-my-codex · error · Error

Invalid setup install mode: ${next}. Expected one of: legacy

Error message

Invalid setup install mode: ${next}. Expected one of: legacy, plugin

What it means

The value after --install-mode must be exactly `legacy` or `plugin`; anything else is rejected. This is a typo/validation guard for the install mode enum.

Source

Thrown at src/cli/index.ts:598

  for (let index = 0; index < args.length; index += 1) {
    const arg = args[index];
    if (arg === "--plugin") {
      setValue("plugin", arg);
      continue;
    }
    if (arg === "--legacy") {
      setValue("legacy", arg);
      continue;
    }
    if (arg === "--install-mode") {
      const next = args[index + 1];
      if (!next || next.startsWith("-")) {
        throw new Error(
          `Missing setup install mode value after --install-mode. Expected one of: legacy, plugin`,
        );
      }
      if (next !== "legacy" && next !== "plugin") {
        throw new Error(
          `Invalid setup install mode: ${next}. Expected one of: legacy, plugin`,
        );
      }
      setValue(next, arg);
      index += 1;
      continue;
    }
    if (arg.startsWith("--install-mode=")) {
      const next = arg.slice("--install-mode=".length);
      if (next !== "legacy" && next !== "plugin") {
        throw new Error(
          `Invalid setup install mode: ${next}. Expected one of: legacy, plugin`,
        );
      }
      setValue(next, "--install-mode");
    }
  }

View on GitHub (pinned to 3ad79a8a6f)

Solutions

1. Correct the value to `legacy` or `plugin` (lowercase)
2. Check the CLI help for supported install modes in your version

Example fix

# before
omx setup --install-mode Plugins
# after
omx setup --install-mode plugin

const INSTALL_MODES = ['legacy', 'plugin'];
const v = args[args.indexOf('--install-mode') + 1];
if (!INSTALL_MODES.includes(v)) throw new Error(`invalid mode: ${v}`);

const isSetupInstallMode = (v: string): v is 'legacy' | 'plugin' => ['legacy','plugin'].includes(v);

When it happens

Trigger: `--install-mode plugins`, `--install-mode Legacy` (wrong case/typo), or any other string.

Common situations: Misspelling, wrong casing, or assuming a mode name from a different version of the tool.

Related errors

• Invalid setup MCP mode: ${next}. Expected one of: none, comp
• Invalid setup scope: ${value}. Expected one of: ${SETUP_SCOP
• Invalid setup Team mode: ${next}. Expected one of: enabled,
• Conflicting setup AGENTS merge policy flags: ${source} confl
• Setup AGENTS merge policy flags do not accept values: ${arg}

AI-assisted analysis of Yeachan-Heo/oh-my-codex@3ad79a8a6f (2026-08-27). Data as JSON: /api/errors/8ee2aa7c4296939a. Report an issue: GitHub.