Github Copilot GPT4.1 incorrect context window #783
Description
In commit e5e859a Github Copilot GPT4.1 was updated to a context window of only 64k. The previous 128k context window was correct based on the API and general usage.
Models API output:
{
"billing": {
"is_premium": false,
"multiplier": 0
},
"capabilities": {
"family": "gpt-4.1",
"limits": {
"max_context_window_tokens": 128000,
"max_output_tokens": 16384,
"max_prompt_tokens": 128000,
"vision": {
"max_prompt_image_size": 3145728,
"max_prompt_images": 1,
"supported_media_types": [
"image/jpeg",
"image/png",
"image/webp",
"image/gif"
]
}
},
"object": "model_capabilities",
"supports": {
"parallel_tool_calls": true,
"streaming": true,
"structured_outputs": true,
"tool_calls": true,
"vision": true
},
"tokenizer": "o200k_base",
"type": "chat"
},
"id": "gpt-4.1",
"is_chat_default": true,
"is_chat_fallback": true,
"model_picker_category": "versatile",
"model_picker_enabled": true,
"name": "GPT-4.1",
"object": "model",
"policy": {
"state": "enabled",
"terms": "Enable access to the latest GPT-4.1 model from OpenAI. [Learn more about how GitHub Copilot serves GPT-4.1](https://docs.github.com/en/copilot/using-github-copilot/ai-models/choosing-the-right-ai-model-for-your-task#gpt-41)."
},
"preview": false,
"vendor": "Azure OpenAI",
"version": "gpt-4.1-2025-04-14"
}