codex - 💡(How to fix) Fix Codex CLI sends invalid tools schema with OpenRouter (works in Codex IDE with identical config) [6 comments, 3 participants]

What version of Codex CLI is running?

v0.121.0)

What subscription do you have?

plus

Which model were you using?

custom

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What terminal emulator and version are you using (if applicable)?

PowerShell

What issue are you seeing?

When using Codex CLI (codex in PowerShell) with an OpenRouter model, every prompt fails with an invalid_prompt error.

Example prompt:

ping

Returned error:

{
  "error": {
    "code": "invalid_prompt",
    "message": "Invalid Responses API request"
  },
  "metadata": {
    "raw": "[ ... ]"
  }
}

Relevant part of the error details:

Invalid input: expected "openrouter:web_search"
Invalid input: expected "openrouter:datetime"
Invalid input: expected "openrouter:image_generation"
Invalid input: expected "openrouter:experimental__search_models"

The error points to invalid entries in:

tools[13] through tools[17]

The same prompt and configuration works correctly in Codex IDE.

What steps can reproduce the bug?

1. Use Codex CLI (v0.121.0) in PowerShell
2. Configure OpenRouter as provider:

• Endpoint: https://openrouter.ai/api/v1
• Model: (e.g. openai/gpt-5)
• Same config.toml and preset as Codex IDE

1. Run: codex
2. Enter any prompt (e.g. ping)

Result:

Request fails with invalid_prompt error Error indicates invalid tools schema

What is the expected behavior?

The model should return a normal response.

This works correctly in Codex IDE using:

• the same model
• the same config.toml
• the same preset

Additional information

Analysis suggests:

• Codex CLI is sending a tools array containing unsupported tool types
• OpenRouter only accepts:
  • type: "openrouter:*"
  • type: "function"
• Codex IDE likely normalizes or filters tools before sending
• Codex CLI appears to forward internal or unsupported tool definitions directly

Disabling tools (if possible) appears to resolve the issue, indicating tool serialization is the root cause.

This prevents using Codex CLI with OpenRouter, despite identical configurations working in Codex IDE.