C3 OpenAI-Compatible Client for Godot

A drop-in Godot 4 client node for OpenAI-compatible HTTP APIs. Works with OpenAI, LM Studio, speaches, and any other server that speaks the OpenAI REST API.

Features

• Chat completions with vision (image input) support
• Text-to-speech (returns a ready-to-play AudioStream)
• Speech-to-text / transcription (AudioStreamMP3 and AudioStreamWAV)
• List available models
• Every method returns a typed response object — check .ok to detect failure

Compatibility

Tested on Godot 4.6.x with automated (GUT) and manual tests. Manually verified to work back to Godot 4.0.0.

Installation

Copy the c3_openai_client/ directory into your project's addons/ directory.

Quick start

1. In your scene, choose Add Child Node and search for C3OpenAIClient.
2. Set Base URL in the Inspector (e.g. https://api.openai.com/v1).
3. Reference it from your scene script:

   @onready var client: C3OpenAIClient = $C3OpenAIClient
   
   func _ready() -> void:
       # Get the API key from an environment variable and set it on the client.
       # You can skip this step for servers that don't require authentication.
       client.api_key = OS.get_environment("OPENAI_API_KEY")
   
       var messages := [
           C3OpenAIClient.make_system_msg("You are a helpful assistant."),
           C3OpenAIClient.make_user_msg("What is the capital of France?"),
       ]
       var opts := C3OpenAIClient.ChatOptions.new()
       opts.model = "gpt-5.4-mini"
   
       var res := await client.chat_completion(messages, opts)
       if res.ok:
           print(res.content)
       else:
           push_error("Chat failed: " + str(res.error))
   

Full example

See examples/openai_client_demo/openai_client_demo.gd for a complete walkthrough covering model listing, chat, vision, TTS, and STT.