server : add VSCode's Github Copilot Chat support

[ggerganov]

Overview

VSCode recently added support to use local models with Github Copilot Chat:

https://code.visualstudio.com/updates/v1_99#_bring-your-own-key-byok-preview

This PR adds compatibility of llama-server with this feature.

Usage

• Start a llama-server on port 11434 with an instruct model of your choice. For example, using Qwen 2.5 Coder Instruct 3B:

  # downloads ~3GB of data
  
  llama-server \
      -hf ggml-org/Qwen2.5-Coder-3B-Instruct-Q8_0-GGUF \
      --port 11434 -fa -ngl 99 -c 0

• In VSCode -> Chat -> Manage models -> select "Ollama" (not sure why it is called like this):

  

• Select the available model from the list and click "OK":

  

• Enjoy local AI assistance using vanilla llama.cpp:

  

• Advanced context reuse for faster prompt reprocessing can be enabled by adding --cache-reuse 256 to the llama-server command

• Speculative decoding is also supported. Simply start the llama-server like this for example:

  llama-server \
      -m  ./models/qwen2.5-32b-coder-instruct/ggml-model-q8_0.gguf \
      -md ./models/qwen2.5-1.5b-coder-instruct/ggml-model-q4_0.gguf \
      --port 11434 -fa -ngl 99 -ngld 99 -c 0 --cache-reuse 256

[ExtReMLapin]

select "Ollama" (not sure why it is called like this):

Sounds like someone just got Edison'd 🤡

[ericcurtin]

There's a lot of tools like this, that work, but don't explicitly say llama.cpp, open-webui is another one (ramalama serve is just vanilla llama-server, but we try and make it easier to use, easier to pull accelerator runtimes and models):

https://github.com./open-webui/docs/pull/455/files

In RamaLama we are going to create a proxy that forks llama-server processes to mimic Ollama to make it even easier to use everyday llama-server.

With most tools if you select generic OpenAI endpoint, llama-server works.

[kabakaev]

@ggerganov, it seems, GET /api/tags API is missing.

At least, my vscode-insiders with github.copilot version 1.308.1532 (updated 2025-04-25, 18:46:22) requests /api/tags and gets HTTP/404 response.