Copilot Proxy

OpenAI-compatible proxy server for GitHub Copilot. Use Copilot models through standard OpenAI API endpoints from any HTTP client.

	CLI	VS Code Extension
Best for	Headless / server / CI use	Local prototyping inside VS Code
Backend	@github/copilot-sdk	VS Code Language Model API
Auth	GITHUB_TOKEN env var or device code flow	VS Code Copilot session
Embeddings	Not supported	Supported (proposed API)
Install	npx @hyorman/copilot-proxy-cli	.vsix package
Docs	CLI README	Extension README

This project is not affiliated with GitHub, Microsoft, or OpenAI. It is intended for research, experimentation, and local prototyping rather than production use.

Acknowledgements

This project was originally inspired by copilot-proxy by Lutz Leonhardt. Thanks to Lutz for publishing the original idea under the MIT License.

Quick Start

CLI

npx @hyorman/copilot-proxy-cli

If GITHUB_TOKEN is unset, the CLI uses the Copilot SDK's device code flow on first run.

VS Code Extension

1. Install the .vsix from Releases.
2. Run Copilot Proxy: Start Server from the Command Palette.

Test it

curl http://localhost:3000/v1/chat/completions \
  -H "Content-Type: application/json" \
  -d '{"model": "gpt-4o", "messages": [{"role": "user", "content": "Hello!"}]}'

API Endpoints

Both modes expose these OpenAI-compatible endpoints:

Method	Path	Description
GET	/v1/models	List available models
POST	/v1/chat/completions	Chat completions (streaming + non-streaming)
POST	/v1/responses	Model responses
POST	/v1/embeddings	Embeddings (VS Code only)
—	/v1/assistants/...	Assistants API
—	/v1/skills/...	Skills API

See the CLI README or Extension README for detailed API docs.

Skills API

The proxy exposes an OpenAI-compatible Skills API at /v1/skills. Skills are versioned file bundles anchored by a SKILL.md manifest.

Skill bundle format

Every bundle must include exactly one SKILL.md file with YAML frontmatter:

---
name: My Skill
description: One-line summary of the skill
---

Detailed instructions for the agent go here.

Additional files (code, data, configs) can be included alongside the manifest.

Endpoints

Method	Path	Description
POST	/v1/skills	Create a skill from multipart or zip upload
GET	/v1/skills	List skills (paginated)
GET	/v1/skills/:id	Retrieve a skill
POST	/v1/skills/:id	Update default version or metadata
DELETE	/v1/skills/:id	Delete a skill and its files
POST	/v1/skills/:id/versions	Upload a new version

Create a skill

curl -X POST http://localhost:3000/v1/skills \
  -H "Authorization: Bearer cpx_your_token" \
  -F "files[]=@SKILL.md" \
  -F "files[]=@helper.py"

Or upload a zip archive:

curl -X POST http://localhost:3000/v1/skills \
  -H "Authorization: Bearer cpx_your_token" \
  -F "files=@my-skill.zip"

Upload a new version

curl -X POST http://localhost:3000/v1/skills/skill_abc123/versions \
  -H "Authorization: Bearer cpx_your_token" \
  -F "files[]=@SKILL.md" \
  -F "files[]=@updated_helper.py"

Update default version

curl -X POST http://localhost:3000/v1/skills/skill_abc123 \
  -H "Authorization: Bearer cpx_your_token" \
  -H "Content-Type: application/json" \
  -d '{"default_version": 2}'

Using skills with the Responses API

Attach skills to a /v1/responses request via the skills field. You can use registered skill references or inline skills.

Skill reference (uses a skill registered via /v1/skills):

curl -X POST http://localhost:3000/v1/responses \
  -H "Authorization: Bearer cpx_your_token" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o",
    "input": "Write a Python function to sort a list.",
    "skills": [
      { "type": "skill_reference", "skill_id": "skill_abc123" }
    ]
  }'

Specific version:

{ "type": "skill_reference", "skill_id": "skill_abc123", "version": 2 }

Inline skill (base64-encoded content, no registration required):

curl -X POST http://localhost:3000/v1/responses \
  -H "Authorization: Bearer cpx_your_token" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o",
    "input": "Refactor this code.",
    "skills": [
      {
        "type": "inline",
        "name": "Code Style",
        "description": "Enforce coding standards",
        "source": {
          "type": "base64",
          "media_type": "text/markdown",
          "data": "QWx3YXlzIHVzZSBUeXBlU2NyaXB0IHN0cmljdCBtb2Rl"
        }
      }
    ]
  }'

Using skills with the Assistants API

Skills can be attached to assistants and runs. When a run executes, skill instructions are resolved and injected into the system prompt alongside the assistant's instructions.

Attach skills to an assistant:

curl -X POST http://localhost:3000/v1/assistants \
  -H "Authorization: Bearer cpx_your_token" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "gpt-4o",
    "name": "My Coding Assistant",
    "instructions": "You are a helpful coding assistant.",
    "skills": [
      { "type": "skill_reference", "skill_id": "skill_abc123" }
    ]
  }'

Override skills on a run:

Skills specified on a run override the assistant's skills for that run:

curl -X POST http://localhost:3000/v1/threads/thread_abc123/runs \
  -H "Authorization: Bearer cpx_your_token" \
  -H "Content-Type: application/json" \
  -d '{
    "assistant_id": "asst_abc123",
    "skills": [
      { "type": "skill_reference", "skill_id": "skill_xyz789", "version": "latest" }
    ]
  }'

If no skills are specified on the run, the assistant's skills are used. If the run specifies an empty skills array, no skills are injected.

Skills in thread-and-run creation:

curl -X POST http://localhost:3000/v1/threads/runs \
  -H "Authorization: Bearer cpx_your_token" \
  -H "Content-Type: application/json" \
  -d '{
    "assistant_id": "asst_abc123",
    "thread": {
      "messages": [{ "role": "user", "content": "Help me write tests." }]
    },
    "skills": [
      { "type": "skill_reference", "skill_id": "skill_abc123" },
      {
        "type": "inline",
        "name": "Test Style",
        "description": "Testing conventions",
        "source": {
          "type": "base64",
          "media_type": "text/markdown",
          "data": "VXNlIGRlc2NyaWJlL2l0IGJsb2NrcyB3aXRoIHZpdGVzdA=="
        }
      }
    ]
  }'

Update assistant skills:

curl -X POST http://localhost:3000/v1/assistants/asst_abc123 \
  -H "Authorization: Bearer cpx_your_token" \
  -H "Content-Type: application/json" \
  -d '{
    "skills": [
      { "type": "skill_reference", "skill_id": "skill_new456" }
    ]
  }'

Development

Project structure

Package	Path	Description
@hyorman/copilot-proxy-core	packages/core	Shared server logic, OpenAI-compatible routes, types
@hyorman/copilot-proxy-cli	packages/cli	CLI proxy server using @github/copilot-sdk
copilot-proxy	packages/vscode	VS Code extension

Build

npm install
npm run build

Test

npm test

Package & Publish

npm run package:vscode    # Package VS Code extension
npm run publish:core      # Publish core to npm
npm run publish:cli       # Publish CLI to npm

License

MIT