feat: add GitHub Copilot Enterprise as API provider

CLAUDE.md

@@ -418,11 +418,18 @@ Run coding agents via Google Cloud Vertex AI:
 
 **Note:** Use `@` instead of `-` in model names for Vertex AI.
 
-### Alternative API Providers (GLM, Ollama, Kimi, Custom)
+### Alternative API Providers (GLM, Ollama, Kimi, GitHub Copilot, Custom)
 
 Alternative providers are configured via the **Settings UI** (gear icon > API Provider section). Select a provider, set the base URL, auth token, and model — no `.env` changes needed.
 
-**Available providers:** Claude (default), GLM (Zhipu AI), Ollama (local models), Kimi (Moonshot), Custom
+**Available providers:** Claude (default), GLM (Zhipu AI), Ollama (local models), Kimi (Moonshot), GitHub Copilot (Enterprise), Custom
+
+**GitHub Copilot (Enterprise) notes:**
+- Uses the [copilot-api](https://github.com/ericc-ch/copilot-api) proxy to expose your GitHub Copilot Enterprise subscription as an Anthropic-compatible API
+- Setup: `npx copilot-api@latest start` (authenticates via GitHub OAuth in browser)
+- Available models: Claude Opus 4.6, Claude Opus 4.6 Fast, GPT 5.2 Codex, GPT 5.3 Codex
+- No API key needed in AutoCoder — the proxy handles authentication
+- Check proxy status: `curl http://localhost:4141/v1/models`
 
 **Ollama notes:**
 - Requires Ollama v0.14.0+ with Anthropic API compatibility

client.py

@@ -345,19 +345,22 @@ def create_client(
     from registry import get_effective_sdk_env
     sdk_env = get_effective_sdk_env()
 
-    # Detect alternative API mode (Ollama, GLM, or Vertex AI)
+    # Detect alternative API mode (Ollama, GLM, GitHub Copilot, or Vertex AI)
     base_url = sdk_env.get("ANTHROPIC_BASE_URL", "")
     is_vertex = sdk_env.get("CLAUDE_CODE_USE_VERTEX") == "1"
     is_alternative_api = bool(base_url) or is_vertex
     is_ollama = "localhost:11434" in base_url or "127.0.0.1:11434" in base_url
     is_azure = "services.ai.azure.com" in base_url
+    is_github_copilot = "localhost:4141" in base_url or "127.0.0.1:4141" in base_url
     model = convert_model_for_vertex(model)
     if sdk_env:
         print(f"   - API overrides: {', '.join(sdk_env.keys())}")
         if is_vertex:
             project_id = sdk_env.get("ANTHROPIC_VERTEX_PROJECT_ID", "unknown")
             region = sdk_env.get("CLOUD_ML_REGION", "unknown")
             print(f"   - Vertex AI Mode: Using GCP project '{project_id}' with model '{model}' in region '{region}'")
+        elif is_github_copilot:
+            print("   - GitHub Copilot Mode: Using copilot-api proxy (auth via GitHub OAuth)")
         elif is_ollama:
             print("   - Ollama Mode: Using local models")
         elif is_azure:

registry.py

@@ -699,6 +699,19 @@ def get_all_settings() -> dict[str, str]:
         ],
         "default_model": "qwen3-coder",
     },
+    "github-copilot": {
+        "name": "GitHub Copilot (Enterprise)",
+        "base_url": "http://localhost:4141",
+        "requires_auth": False,  # copilot-api handles auth via GitHub OAuth
+        "models": [
+            {"id": "claude-opus-4.6", "name": "Claude Opus 4.6"},
+            {"id": "claude-opus-4.6-fast", "name": "Claude Opus 4.6 Fast"},
+            {"id": "gpt-5.2-codex", "name": "GPT 5.2 Codex"},
+            {"id": "gpt-5.3-codex", "name": "GPT 5.3 Codex"},
+        ],
+        "default_model": "claude-opus-4.6",
+        "setup_instructions": "npx copilot-api@latest start",
+    },
     "custom": {
         "name": "Custom Provider",
         "base_url": "",

ui/src/components/SettingsModal.tsx

@@ -24,6 +24,7 @@ const PROVIDER_INFO_TEXT: Record<string, string> = {
   kimi: 'Get an API key at kimi.com',
   glm: 'Get an API key at open.bigmodel.cn',
   ollama: 'Run models locally. Install from ollama.com',
+  'github-copilot': 'Requires copilot-api proxy. Run: npx copilot-api@latest start',
   custom: 'Connect to any OpenAI-compatible API endpoint.',
 }