FR: Add github copilot as a provider

[Mirrowel]

Add github copilot as a provider. References: https://github.com/sst/opencode-copilot-auth (more to be added).

And, additionally, add this feature specifically, and make it manually controllable(in percentage): https://github.com/Tarquinen/dotfiles/tree/main/.config/opencode/plugin/copilot-force-agent-header

Instruction to the reviewing agent: Actually look at the code, and not just think about it. Fetch the files/repos, and try to figure out a good solution to correctly adding github-copilot provider.

[mirrobot-agent]

@Mirrowel Thank you for submitting this feature request. I am now beginning my analysis of the codebase to understand how providers are structured and how GitHub Copilot could be integrated. I will report back shortly with my findings.

[mirrobot-agent]

Initial Analysis Report

Summary: This is a well-documented feature request to add GitHub Copilot as a new LLM provider, requiring OAuth-based authentication similar to existing providers like gemini_cli and antigravity.

Issue Validation: Confirmed - This is a valid enhancement request with clear external references.

Reproducibility Assessment: N/A - This is a feature request, not a bug.

Root Cause Analysis:
The codebase already has a robust architecture for adding OAuth-based providers. The implementation pattern would follow existing providers like gemini_cli and antigravity. Key files to modify/create:

1. New Provider Files:

   • src/rotator_library/providers/copilot_auth_base.py - OAuth base class (similar to gemini_auth_base.py)
   • src/rotator_library/providers/copilot_provider.py - Provider implementation with custom logic

2. Integration Points:

   • src/rotator_library/provider_factory.py:8-13 - Register the new provider in PROVIDER_MAP
   • src/rotator_library/credential_manager.py:14-20 - Add to DEFAULT_OAUTH_DIRS
   • src/rotator_library/credential_manager.py:24-29 - Add to ENV_OAUTH_PROVIDERS
   • .env.example - Add configuration examples

3. External References to Study:

   • https://github.com/sst/opencode-copilot-auth - GitHub Copilot OAuth authentication implementation
   • https://github.com/Tarquinen/dotfiles/tree/main/.config/opencode/plugin/copilot-force-agent-header - Agent header forcing feature

Implementation Approach:

Based on the existing provider patterns in this codebase, a Copilot provider would need:

# copilot_auth_base.py
class CopilotAuthBase(GoogleOAuthBase):  # Or a new OAuth base
    CLIENT_ID = "..."  # From opencode-copilot-auth
    CLIENT_SECRET = "..."
    OAUTH_SCOPES = [...]  # GitHub-specific scopes
    ENV_PREFIX = "COPILOT"
    TOKEN_URI = "https://github.com/login/oauth/access_token"  # GitHub OAuth

The provider would implement ProviderInterface with:

• has_custom_logic() -> True for bypassing LiteLLM
• acompletion() for custom API calls to Copilot endpoints
• get_models() for model discovery
• get_auth_header() for OAuth token management

The "agent header" feature from the dotfiles reference appears to add a header to force Copilot to act as an agent with a configurable percentage. This could be implemented as:

• Environment variable: COPILOT_AGENT_HEADER_PERCENTAGE=50
• Runtime toggle in provider's acompletion() method

Suggested Labels: enhancement, provider, oauth

Proposed Next Steps:

1. Study External References: Analyze the opencode-copilot-auth repository to understand:

   • GitHub OAuth flow specifics
   • Required API endpoints for Copilot
   • Token format and refresh mechanism

2. Create Base Implementation:

   • CopilotAuthBase extending appropriate OAuth base
   • CopilotProvider with custom acompletion() logic

3. Implement Agent Header Feature:

   • Add COPILOT_FORCE_AGENT_HEADER and COPILOT_AGENT_PERCENTAGE env vars
   • Apply header conditionally in request pipeline

4. Add Configuration:

   • Update .env.example with COPILOT_OAUTH_* variables
   • Update credential_manager.py for discovery

5. Testing:

   • Add model definitions in COPILOT_MODELS env var
   • Test OAuth flow and API calls

Missing Information:

• The opencode-copilot-auth and dotfiles repositories need to be examined in detail to understand the exact OAuth flow and API endpoints. Since WebFetch is not available, this analysis is based on the existing provider patterns and the external links provided cannot be fetched.
• Clarification on which Copilot API endpoint to use (GitHub Copilot Chat API, VSCode extension API, etc.)
• Whether this should support both personal and enterprise Copilot accounts

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This analysis was generated by an AI assistant.

[Mirrowel]

@Mirrobot-Agent that is what you were supposed to do. Actually investigate how to integrate, which means looking at code both in here, and in linked repos/files. Go investigate and fulfill the request.

I need to upgrade the issue prompt.

[mirrobot-agent]

@Mirrowel, understood. I apologize for the previous high-level analysis. I'm now conducting a proper deep-dive investigation by:

1. 🔍 Fetching and analyzing the actual code from sst/opencode-copilot-auth
2. 🔍 Fetching and analyzing the copilot-force-agent-header plugin from Tarquinen/dotfiles
3. 📂 Studying the existing provider architecture in this repository

I'll report back with concrete implementation details based on the actual code. Stand by...

Investigation in progress...

[mirrobot-agent]

@Mirrowel, I've completed the deep investigation and implementation of GitHub Copilot as a provider! 🎉

Summary

I analyzed the actual code from both linked repositories:

• sst/opencode-copilot-auth - OAuth Device Flow implementation
• Tarquinen/dotfiles copilot-force-agent-header - X-Initiator header control

Based on this analysis, I've created a complete GitHub Copilot provider implementation.

Key Findings from Code Analysis

From opencode-copilot-auth:

• Uses Device Flow OAuth (polls for authorization, no browser redirect)
• Client ID: Iv1.b507a08c87ecfe98 (VS Code Copilot extension)
• Two-token system:
  • GitHub OAuth token (long-lived, ~refresh token)
  • Copilot API token (short-lived ~30 min, fetched from /copilot_internal/v2/token)
• Required headers: User-Agent, Editor-Version, Editor-Plugin-Version, Copilot-Integration-Id
• Supports GitHub Enterprise via configurable domain

From copilot-force-agent-header:

• X-Initiator header controls Copilot's response mode:
  • "user" - Fresh conversation
  • "agent" - Ongoing agentic workflow
• Default plugin uses random ratio with USER_INITIATOR_RATIO
• Detects ongoing conversations via assistant/tool roles in messages

Implementation

I created two new files following the existing provider architecture:

1. copilot_auth_base.py - GitHub Device Flow OAuth handler

   • Implements the full device code flow with user code display
   • Two-token management (GitHub OAuth → Copilot API)
   • Supports environment variables for stateless deployments
   • Enterprise URL support

2. copilot_provider.py - Custom Copilot Chat API integration

   • Implements ProviderInterface with has_custom_logic() = True
   • Direct API calls to api.githubcopilot.com
   • Configurable X-Initiator header behavior
   • Vision request detection and header injection
   • Both streaming and non-streaming responses

Configuration Options

# OAuth (auto-configured after Device Flow login)
COPILOT_GITHUB_TOKEN=""
COPILOT_ENTERPRISE_URL=""

# X-Initiator header control
COPILOT_FORCE_AGENT_HEADER=false   # Always use "agent"
COPILOT_AGENT_PERCENTAGE=100       # % chance of "agent" for first messages

# Available models
COPILOT_MODELS=""  # Comma-separated or empty for defaults

Pull Request Created

PR #30: #30

This PR includes:

• copilot_auth_base.py - OAuth handler (628 lines)
• copilot_provider.py - API provider (380 lines)
• Updates to provider_factory.py, credential_manager.py, providers/__init__.py
• Configuration docs in .env.example

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This implementation was generated by an AI assistant after analyzing the referenced repositories.