feat: add github copilot provider

Author: bryanvaz

.gitignore

@@ -44,3 +44,4 @@ Thumbs.db
 .opencode/
 
 opencode
+opencode.md

README.md

@@ -91,22 +91,23 @@ You can enable or disable this feature in your configuration file:
 
 You can configure OpenCode using environment variables:
 
-| Environment Variable       | Purpose                                                |
-| -------------------------- | ------------------------------------------------------ |
-| `ANTHROPIC_API_KEY`        | For Claude models                                      |
-| `OPENAI_API_KEY`           | For OpenAI models                                      |
-| `GEMINI_API_KEY`           | For Google Gemini models                               |
-| `VERTEXAI_PROJECT`         | For Google Cloud VertexAI (Gemini)                     |
-| `VERTEXAI_LOCATION`        | For Google Cloud VertexAI (Gemini)                     |
-| `GROQ_API_KEY`             | For Groq models                                        |
-| `AWS_ACCESS_KEY_ID`        | For AWS Bedrock (Claude)                               |
-| `AWS_SECRET_ACCESS_KEY`    | For AWS Bedrock (Claude)                               |
-| `AWS_REGION`               | For AWS Bedrock (Claude)                               |
-| `AZURE_OPENAI_ENDPOINT`    | For Azure OpenAI models                                |
-| `AZURE_OPENAI_API_KEY`     | For Azure OpenAI models (optional when using Entra ID) |
-| `AZURE_OPENAI_API_VERSION` | For Azure OpenAI models                                |
-| `LOCAL_ENDPOINT`           | For self-hosted models                                 |
-| `SHELL`                    | Default shell to use (if not specified in config)      |
+| Environment Variable       | Purpose                                                                          |
+| -------------------------- | -------------------------------------------------------------------------------- |
+| `ANTHROPIC_API_KEY`        | For Claude models                                                                |
+| `OPENAI_API_KEY`           | For OpenAI models                                                                |
+| `GEMINI_API_KEY`           | For Google Gemini models                                                         |
+| `GITHUB_TOKEN`             | For Github Copilot models (see [Using Github Copilot](#using-github-copilot))    |
+| `VERTEXAI_PROJECT`         | For Google Cloud VertexAI (Gemini)                                               |
+| `VERTEXAI_LOCATION`        | For Google Cloud VertexAI (Gemini)                                               |
+| `GROQ_API_KEY`             | For Groq models                                                                  |
+| `AWS_ACCESS_KEY_ID`        | For AWS Bedrock (Claude)                                                         |
+| `AWS_SECRET_ACCESS_KEY`    | For AWS Bedrock (Claude)                                                         |
+| `AWS_REGION`               | For AWS Bedrock (Claude)                                                         |
+| `AZURE_OPENAI_ENDPOINT`    | For Azure OpenAI models                                                          |
+| `AZURE_OPENAI_API_KEY`     | For Azure OpenAI models (optional when using Entra ID)                           |
+| `AZURE_OPENAI_API_VERSION` | For Azure OpenAI models                                                          |
+| `LOCAL_ENDPOINT`           | For self-hosted models                                                           |
+| `SHELL`                    | Default shell to use (if not specified in config)                                |
 
 ### Shell Configuration
 
@@ -141,6 +142,9 @@ This is useful if you want to use a different shell than your default system she
       "apiKey": "your-api-key",
       "disabled": false
     },
+    "copilot": {
+      "disabled": false
+    },
     "groq": {
       "apiKey": "your-api-key",
       "disabled": false
@@ -211,6 +215,23 @@ OpenCode supports a variety of AI models from different providers:
 - Claude 3 Haiku
 - Claude 3 Opus
 
+### GitHub Copilot
+
+- GPT-3.5 Turbo
+- GPT-4
+- GPT-4o
+- GPT-4o Mini
+- GPT-4.1
+- Claude 3.5 Sonnet
+- Claude 3.7 Sonnet
+- Claude 3.7 Sonnet Thinking
+- Claude Sonnet 4
+- O1
+- O3 Mini
+- O4 Mini
+- Gemini 2.0 Flash
+- Gemini 2.5 Pro
+
 ### Google
 
 - Gemini 2.5
@@ -574,6 +595,25 @@ The AI assistant can access LSP features through the `diagnostics` tool, allowin
 
 While the LSP client implementation supports the full LSP protocol (including completions, hover, definition, etc.), currently only diagnostics are exposed to the AI assistant.
 
+## Using Github Copilot
+
+_Copilot support is currently experimental._
+
+### Requirements
+- [Copilot chat in the IDE](https://github.com/settings/copilot) enabled in GitHub settings
+- One of:
+  - VSCode Github Copilot chat extension
+  - Github `gh` CLI
+  - Neovim Github Copilot plugin (`copilot.vim` or `copilot.lua`)
+  - Github token with copilot permissions
+
+If using one of the above plugins or cli tools, make sure you use the authenticate
+the tool with your github account. This should create a github token at one of the following locations:
+- ~/.config/github-copilot/[hosts,apps].json
+- $XDG_CONFIG_HOME/github-copilot/[hosts,apps].json
+
+If using an explicit github token, you may either set the $GITHUB_TOKEN environment variable or add it to the opencode.json config file at `providers.copilot.apiKey`.
+
 ## Using a self-hosted model provider
 
 OpenCode can also load and use models from a self-hosted (OpenAI-like) provider.

internal/config/config.go

@@ -7,6 +7,7 @@ import (
 	"log/slog"
 	"os"
 	"path/filepath"
+	"runtime"
 	"strings"
 
 	"github.com/opencode-ai/opencode/internal/llm/models"
@@ -245,6 +246,7 @@ func setDefaults(debug bool) {
 // environment variables and configuration file.
 func setProviderDefaults() {
 	// Set all API keys we can find in the environment
+	// Note: Viper does not default if the json apiKey is ""
 	if apiKey := os.Getenv("ANTHROPIC_API_KEY"); apiKey != "" {
 		viper.SetDefault("providers.anthropic.apiKey", apiKey)
 	}
@@ -267,16 +269,32 @@ func setProviderDefaults() {
 		// api-key may be empty when using Entra ID credentials – that's okay
 		viper.SetDefault("providers.azure.apiKey", os.Getenv("AZURE_OPENAI_API_KEY"))
 	}
+	if apiKey, err := LoadGitHubToken(); err == nil && apiKey != "" {
+		viper.SetDefault("providers.copilot.apiKey", apiKey)
+		if viper.GetString("providers.copilot.apiKey") == "" {
+			viper.Set("providers.copilot.apiKey", apiKey)
+		}
+	}
 
 	// Use this order to set the default models
-	// 1. Anthropic
-	// 2. OpenAI
-	// 3. Google Gemini
-	// 4. Groq
-	// 5. OpenRouter
-	// 6. AWS Bedrock
-	// 7. Azure
-	// 8. Google Cloud VertexAI
+	// 1. Copilot
+	// 2. Anthropic
+	// 3. OpenAI
+	// 4. Google Gemini
+	// 5. Groq
+	// 6. OpenRouter
+	// 7. AWS Bedrock
+	// 8. Azure
+	// 9. Google Cloud VertexAI
+
+	// copilot configuration
+	if key := viper.GetString("providers.copilot.apiKey"); strings.TrimSpace(key) != "" {
+		viper.SetDefault("agents.coder.model", models.CopilotGPT4o)
+		viper.SetDefault("agents.summarizer.model", models.CopilotGPT4o)
+		viper.SetDefault("agents.task.model", models.CopilotGPT4o)
+		viper.SetDefault("agents.title.model", models.CopilotGPT4o)
+		return
+	}
 
 	// Anthropic configuration
 	if key := viper.GetString("providers.anthropic.apiKey"); strings.TrimSpace(key) != "" {
@@ -399,6 +417,14 @@ func hasVertexAICredentials() bool {
 	return false
 }
 
+func hasCopilotCredentials() bool {
+	// Check for explicit Copilot parameters
+	if token, _ := LoadGitHubToken(); token != "" {
+		return true
+	}
+	return false
+}
+
 // readConfig handles the result of reading a configuration file.
 func readConfig(err error) error {
 	if err == nil {
@@ -440,6 +466,9 @@ func applyDefaultValues() {
 // It validates model IDs and providers, ensuring they are supported.
 func validateAgent(cfg *Config, name AgentName, agent Agent) error {
 	// Check if model exists
+	// TODO:	If a copilot model is specified, but model is not found,
+	// 		 	it might be new model. The https://api.githubcopilot.com/models
+	// 		 	endpoint should be queried to validate if the model is supported.
 	model, modelExists := models.SupportedModels[agent.Model]
 	if !modelExists {
 		logging.Warn("unsupported model configured, reverting to default",
@@ -584,6 +613,7 @@ func Validate() error {
 	// Validate providers
 	for provider, providerCfg := range cfg.Providers {
 		if providerCfg.APIKey == "" && !providerCfg.Disabled {
+			fmt.Printf("provider has no API key, marking as disabled %s", provider)
 			logging.Warn("provider has no API key, marking as disabled", "provider", provider)
 			providerCfg.Disabled = true
 			cfg.Providers[provider] = providerCfg
@@ -631,6 +661,18 @@ func getProviderAPIKey(provider models.ModelProvider) string {
 
 // setDefaultModelForAgent sets a default model for an agent based on available providers
 func setDefaultModelForAgent(agent AgentName) bool {
+	if hasCopilotCredentials() {
+		maxTokens := int64(5000)
+		if agent == AgentTitle {
+			maxTokens = 80
+		}
+
+		cfg.Agents[agent] = Agent{
+			Model:     models.CopilotGPT4o,
+			MaxTokens: maxTokens,
+		}
+		return true
+	}
 	// Check providers in order of preference
 	if apiKey := os.Getenv("ANTHROPIC_API_KEY"); apiKey != "" {
 		maxTokens := int64(5000)
@@ -878,3 +920,53 @@ func UpdateTheme(themeName string) error {
 		config.TUI.Theme = themeName
 	})
 }
+
+// Tries to load Github token from all possible locations
+func LoadGitHubToken() (string, error) {
+	// First check environment variable
+	if token := os.Getenv("GITHUB_TOKEN"); token != "" {
+		return token, nil
+	}
+
+	// Get config directory
+	var configDir string
+	if xdgConfig := os.Getenv("XDG_CONFIG_HOME"); xdgConfig != "" {
+		configDir = xdgConfig
+	} else if runtime.GOOS == "windows" {
+		if localAppData := os.Getenv("LOCALAPPDATA"); localAppData != "" {
+			configDir = localAppData
+		} else {
+			configDir = filepath.Join(os.Getenv("HOME"), "AppData", "Local")
+		}
+	} else {
+		configDir = filepath.Join(os.Getenv("HOME"), ".config")
+	}
+
+	// Try both hosts.json and apps.json files
+	filePaths := []string{
+		filepath.Join(configDir, "github-copilot", "hosts.json"),
+		filepath.Join(configDir, "github-copilot", "apps.json"),
+	}
+
+	for _, filePath := range filePaths {
+		data, err := os.ReadFile(filePath)
+		if err != nil {
+			continue
+		}
+
+		var config map[string]map[string]interface{}
+		if err := json.Unmarshal(data, &config); err != nil {
+			continue
+		}
+
+		for key, value := range config {
+			if strings.Contains(key, "github.com") {
+				if oauthToken, ok := value["oauth_token"].(string); ok {
+					return oauthToken, nil
+				}
+			}
+		}
+	}
+
+	return "", fmt.Errorf("GitHub token not found in standard locations")
+}