feat: add github copilot provider (#230)

* feat: add github copilot

* fix: add support for claude4

.gitignore

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

README.md

@@ -97,10 +97,11 @@ 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                                                         |
+| `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                                                                  |
@@ -146,6 +147,9 @@ 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
@@ -216,6 +220,23 @@ 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
@@ -579,6 +600,25 @@ 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"
@@ -161,6 +162,7 @@ func Load(workingDir string, debug bool) (*Config, error) {
 	}
 	if os.Getenv("OPENCODE_DEV_DEBUG") == "true" {
 		loggingFile := fmt.Sprintf("%s/%s", cfg.Data.Directory, "debug.log")
+		messagesPath := fmt.Sprintf("%s/%s", cfg.Data.Directory, "messages")
 
 		// if file does not exist create it
 		if _, err := os.Stat(loggingFile); os.IsNotExist(err) {
@@ -172,6 +174,13 @@ func Load(workingDir string, debug bool) (*Config, error) {
 			}
 		}
 
+		if _, err := os.Stat(messagesPath); os.IsNotExist(err) {
+			if err := os.MkdirAll(messagesPath, 0o756); err != nil {
+				return cfg, fmt.Errorf("failed to create directory: %w", err)
+			}
+		}
+		logging.MessageDir = messagesPath
+
 		sloggingFileWriter, err := os.OpenFile(loggingFile, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0o666)
 		if err != nil {
 			return cfg, fmt.Errorf("failed to open log file: %w", err)
@@ -245,6 +254,7 @@ 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 +277,32 @@ 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
+	// 1. Copilot
-	// 2. OpenAI
+	// 2. Anthropic
-	// 3. Google Gemini
+	// 3. OpenAI
-	// 4. Groq
+	// 4. Google Gemini
-	// 5. OpenRouter
+	// 5. Groq
-	// 6. AWS Bedrock
+	// 6. OpenRouter
-	// 7. Azure
+	// 7. AWS Bedrock
-	// 8. Google Cloud VertexAI
+	// 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 +425,14 @@ 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 +474,9 @@ 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 +621,7 @@ 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 +669,18 @@ 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 +928,53 @@ 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")
+}

internal/llm/agent/agent.go

@@ -162,6 +162,7 @@ func (a *agent) generateTitle(ctx context.Context, sessionID string, content str
 	if err != nil {
 		return err
 	}
+	ctx = context.WithValue(ctx, tools.SessionIDContextKey, sessionID)
 	parts := []message.ContentPart{message.TextContent{Text: content}}
 	response, err := a.titleProvider.SendMessages(
 		ctx,
@@ -230,6 +231,7 @@ func (a *agent) Run(ctx context.Context, sessionID string, content string, attac
 }
 
 func (a *agent) processGeneration(ctx context.Context, sessionID, content string, attachmentParts []message.ContentPart) AgentEvent {
+	cfg := config.Get()
 	// List existing messages; if none, start title generation asynchronously.
 	msgs, err := a.messages.List(ctx, sessionID)
 	if err != nil {
@@ -288,7 +290,13 @@ func (a *agent) processGeneration(ctx context.Context, sessionID, content string
 			}
 			return a.err(fmt.Errorf("failed to process events: %w", err))
 		}
+		if cfg.Debug {
+			seqId := (len(msgHistory) + 1) / 2
+			toolResultFilepath := logging.WriteToolResultsJson(sessionID, seqId, toolResults)
+			logging.Info("Result", "message", agentMessage.FinishReason(), "toolResults", "{}", "filepath", toolResultFilepath)
+		} else {
 			logging.Info("Result", "message", agentMessage.FinishReason(), "toolResults", toolResults)
+		}
 		if (agentMessage.FinishReason() == message.FinishReasonToolUse) && toolResults != nil {
 			// We are not done, we need to respond with the tool response
 			msgHistory = append(msgHistory, agentMessage, *toolResults)
@@ -312,6 +320,7 @@ func (a *agent) createUserMessage(ctx context.Context, sessionID, content string
 }
 
 func (a *agent) streamAndHandleEvents(ctx context.Context, sessionID string, msgHistory []message.Message) (message.Message, *message.Message, error) {
+	ctx = context.WithValue(ctx, tools.SessionIDContextKey, sessionID)
 	eventChan := a.provider.StreamResponse(ctx, msgHistory, a.tools)
 
 	assistantMsg, err := a.messages.Create(ctx, sessionID, message.CreateMessageParams{
@@ -325,7 +334,6 @@ func (a *agent) streamAndHandleEvents(ctx context.Context, sessionID string, msg
 
 	// Add the session and message ID into the context if needed by tools.
 	ctx = context.WithValue(ctx, tools.MessageIDContextKey, assistantMsg.ID)
-	ctx = context.WithValue(ctx, tools.SessionIDContextKey, sessionID)
 
 	// Process each event in the stream.
 	for event := range eventChan {
@@ -357,10 +365,17 @@ func (a *agent) streamAndHandleEvents(ctx context.Context, sessionID string, msg
 		default:
 			// Continue processing
 			var tool tools.BaseTool
-			for _, availableTools := range a.tools {
+			for _, availableTool := range a.tools {
-				if availableTools.Info().Name == toolCall.Name {
+				if availableTool.Info().Name == toolCall.Name {
-					tool = availableTools
+					tool = availableTool
+					break
 				}
+				// Monkey patch for Copilot Sonnet-4 tool repetition obfuscation
+				// if strings.HasPrefix(toolCall.Name, availableTool.Info().Name) &&
+				// 	strings.HasPrefix(toolCall.Name, availableTool.Info().Name+availableTool.Info().Name) {
+				// 	tool = availableTool
+				// 	break
+				// }
 			}
 
 			// Tool not found
@@ -553,6 +568,7 @@ func (a *agent) Summarize(ctx context.Context, sessionID string) error {
 			a.Publish(pubsub.CreatedEvent, event)
 			return
 		}
+		summarizeCtx = context.WithValue(summarizeCtx, tools.SessionIDContextKey, sessionID)
 
 		if len(msgs) == 0 {
 			event = AgentEvent{

internal/llm/models/copilot.go

@@ -0,0 +1,219 @@
+package models
+
+const (
+	ProviderCopilot ModelProvider = "copilot"
+
+	// GitHub Copilot models
+	CopilotGTP35Turbo      ModelID = "copilot.gpt-3.5-turbo"
+	CopilotGPT4o           ModelID = "copilot.gpt-4o"
+	CopilotGPT4oMini       ModelID = "copilot.gpt-4o-mini"
+	CopilotGPT41           ModelID = "copilot.gpt-4.1"
+	CopilotClaude35        ModelID = "copilot.claude-3.5-sonnet"
+	CopilotClaude37        ModelID = "copilot.claude-3.7-sonnet"
+	CopilotClaude4         ModelID = "copilot.claude-sonnet-4"
+	CopilotO1              ModelID = "copilot.o1"
+	CopilotO3Mini          ModelID = "copilot.o3-mini"
+	CopilotO4Mini          ModelID = "copilot.o4-mini"
+	CopilotGemini20        ModelID = "copilot.gemini-2.0-flash"
+	CopilotGemini25        ModelID = "copilot.gemini-2.5-pro"
+	CopilotGPT4            ModelID = "copilot.gpt-4"
+	CopilotClaude37Thought ModelID = "copilot.claude-3.7-sonnet-thought"
+)
+
+var CopilotAnthropicModels = []ModelID{
+	CopilotClaude35,
+	CopilotClaude37,
+	CopilotClaude37Thought,
+	CopilotClaude4,
+}
+
+// GitHub Copilot models available through GitHub's API
+var CopilotModels = map[ModelID]Model{
+	CopilotGTP35Turbo: {
+		ID:                  CopilotGTP35Turbo,
+		Name:                "GitHub Copilot GPT-3.5-turbo",
+		Provider:            ProviderCopilot,
+		APIModel:            "gpt-3.5-turbo",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       16_384,
+		DefaultMaxTokens:    4096,
+		SupportsAttachments: true,
+	},
+	CopilotGPT4o: {
+		ID:                  CopilotGPT4o,
+		Name:                "GitHub Copilot GPT-4o",
+		Provider:            ProviderCopilot,
+		APIModel:            "gpt-4o",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       128_000,
+		DefaultMaxTokens:    16384,
+		SupportsAttachments: true,
+	},
+	CopilotGPT4oMini: {
+		ID:                  CopilotGPT4oMini,
+		Name:                "GitHub Copilot GPT-4o Mini",
+		Provider:            ProviderCopilot,
+		APIModel:            "gpt-4o-mini",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       128_000,
+		DefaultMaxTokens:    4096,
+		SupportsAttachments: true,
+	},
+	CopilotGPT41: {
+		ID:                  CopilotGPT41,
+		Name:                "GitHub Copilot GPT-4.1",
+		Provider:            ProviderCopilot,
+		APIModel:            "gpt-4.1",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       128_000,
+		DefaultMaxTokens:    16384,
+		CanReason:           true,
+		SupportsAttachments: true,
+	},
+	CopilotClaude35: {
+		ID:                  CopilotClaude35,
+		Name:                "GitHub Copilot Claude 3.5 Sonnet",
+		Provider:            ProviderCopilot,
+		APIModel:            "claude-3.5-sonnet",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       90_000,
+		DefaultMaxTokens:    8192,
+		SupportsAttachments: true,
+	},
+	CopilotClaude37: {
+		ID:                  CopilotClaude37,
+		Name:                "GitHub Copilot Claude 3.7 Sonnet",
+		Provider:            ProviderCopilot,
+		APIModel:            "claude-3.7-sonnet",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       200_000,
+		DefaultMaxTokens:    16384,
+		SupportsAttachments: true,
+	},
+	CopilotClaude4: {
+		ID:                  CopilotClaude4,
+		Name:                "GitHub Copilot Claude Sonnet 4",
+		Provider:            ProviderCopilot,
+		APIModel:            "claude-sonnet-4",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       128_000,
+		DefaultMaxTokens:    16000,
+		SupportsAttachments: true,
+	},
+	CopilotO1: {
+		ID:                  CopilotO1,
+		Name:                "GitHub Copilot o1",
+		Provider:            ProviderCopilot,
+		APIModel:            "o1",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       200_000,
+		DefaultMaxTokens:    100_000,
+		CanReason:           true,
+		SupportsAttachments: false,
+	},
+	CopilotO3Mini: {
+		ID:                  CopilotO3Mini,
+		Name:                "GitHub Copilot o3-mini",
+		Provider:            ProviderCopilot,
+		APIModel:            "o3-mini",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       200_000,
+		DefaultMaxTokens:    100_000,
+		CanReason:           true,
+		SupportsAttachments: false,
+	},
+	CopilotO4Mini: {
+		ID:                  CopilotO4Mini,
+		Name:                "GitHub Copilot o4-mini",
+		Provider:            ProviderCopilot,
+		APIModel:            "o4-mini",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       128_000,
+		DefaultMaxTokens:    16_384,
+		CanReason:           true,
+		SupportsAttachments: true,
+	},
+	CopilotGemini20: {
+		ID:                  CopilotGemini20,
+		Name:                "GitHub Copilot Gemini 2.0 Flash",
+		Provider:            ProviderCopilot,
+		APIModel:            "gemini-2.0-flash-001",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       1_000_000,
+		DefaultMaxTokens:    8192,
+		SupportsAttachments: true,
+	},
+	CopilotGemini25: {
+		ID:                  CopilotGemini25,
+		Name:                "GitHub Copilot Gemini 2.5 Pro",
+		Provider:            ProviderCopilot,
+		APIModel:            "gemini-2.5-pro",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       128_000,
+		DefaultMaxTokens:    64000,
+		SupportsAttachments: true,
+	},
+	CopilotGPT4: {
+		ID:                  CopilotGPT4,
+		Name:                "GitHub Copilot GPT-4",
+		Provider:            ProviderCopilot,
+		APIModel:            "gpt-4",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       32_768,
+		DefaultMaxTokens:    4096,
+		SupportsAttachments: true,
+	},
+	CopilotClaude37Thought: {
+		ID:                  CopilotClaude37Thought,
+		Name:                "GitHub Copilot Claude 3.7 Sonnet Thinking",
+		Provider:            ProviderCopilot,
+		APIModel:            "claude-3.7-sonnet-thought",
+		CostPer1MIn:         0.0, // Included in GitHub Copilot subscription
+		CostPer1MInCached:   0.0,
+		CostPer1MOutCached:  0.0,
+		CostPer1MOut:        0.0,
+		ContextWindow:       200_000,
+		DefaultMaxTokens:    16384,
+		CanReason:           true,
+		SupportsAttachments: true,
+	},
+}

internal/llm/models/models.go

@@ -36,14 +36,15 @@ const (
 
 // Providers in order of popularity
 var ProviderPopularity = map[ModelProvider]int{
-	ProviderAnthropic:  1,
+	ProviderCopilot:    1,
-	ProviderOpenAI:     2,
+	ProviderAnthropic:  2,
-	ProviderGemini:     3,
+	ProviderOpenAI:     3,
-	ProviderGROQ:       4,
+	ProviderGemini:     4,
-	ProviderOpenRouter: 5,
+	ProviderGROQ:       5,
-	ProviderBedrock:    6,
+	ProviderOpenRouter: 6,
-	ProviderAzure:      7,
+	ProviderBedrock:    7,
-	ProviderVertexAI:   8,
+	ProviderAzure:      8,
+	ProviderVertexAI:   9,
 }
 
 var SupportedModels = map[ModelID]Model{
@@ -93,4 +94,5 @@ func init() {
 	maps.Copy(SupportedModels, OpenRouterModels)
 	maps.Copy(SupportedModels, XAIModels)
 	maps.Copy(SupportedModels, VertexAIGeminiModels)
+	maps.Copy(SupportedModels, CopilotModels)
 }

internal/llm/provider/anthropic.go

@@ -14,7 +14,7 @@ import (
 	"github.com/anthropics/anthropic-sdk-go/option"
 	"github.com/opencode-ai/opencode/internal/config"
 	"github.com/opencode-ai/opencode/internal/llm/models"
-	"github.com/opencode-ai/opencode/internal/llm/tools"
+	toolsPkg "github.com/opencode-ai/opencode/internal/llm/tools"
 	"github.com/opencode-ai/opencode/internal/logging"
 	"github.com/opencode-ai/opencode/internal/message"
 )
@@ -118,7 +118,7 @@ func (a *anthropicClient) convertMessages(messages []message.Message) (anthropic
 	return
 }
 
-func (a *anthropicClient) convertTools(tools []tools.BaseTool) []anthropic.ToolUnionParam {
+func (a *anthropicClient) convertTools(tools []toolsPkg.BaseTool) []anthropic.ToolUnionParam {
 	anthropicTools := make([]anthropic.ToolUnionParam, len(tools))
 
 	for i, tool := range tools {
@@ -195,7 +195,7 @@ func (a *anthropicClient) preparedMessages(messages []anthropic.MessageParam, to
 	}
 }
 
-func (a *anthropicClient) send(ctx context.Context, messages []message.Message, tools []tools.BaseTool) (resposne *ProviderResponse, err error) {
+func (a *anthropicClient) send(ctx context.Context, messages []message.Message, tools []toolsPkg.BaseTool) (resposne *ProviderResponse, err error) {
 	preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
 	cfg := config.Get()
 	if cfg.Debug {
@@ -244,12 +244,24 @@ func (a *anthropicClient) send(ctx context.Context, messages []message.Message,
 	}
 }
 
-func (a *anthropicClient) stream(ctx context.Context, messages []message.Message, tools []tools.BaseTool) <-chan ProviderEvent {
+func (a *anthropicClient) stream(ctx context.Context, messages []message.Message, tools []toolsPkg.BaseTool) <-chan ProviderEvent {
 	preparedMessages := a.preparedMessages(a.convertMessages(messages), a.convertTools(tools))
 	cfg := config.Get()
+
+	var sessionId string
+	requestSeqId := (len(messages) + 1) / 2
 	if cfg.Debug {
-		// jsonData, _ := json.Marshal(preparedMessages)
+		if sid, ok := ctx.Value(toolsPkg.SessionIDContextKey).(string); ok {
-		// logging.Debug("Prepared messages", "messages", string(jsonData))
+			sessionId = sid
+		}
+		jsonData, _ := json.Marshal(preparedMessages)
+		if sessionId != "" {
+			filepath := logging.WriteRequestMessageJson(sessionId, requestSeqId, preparedMessages)
+			logging.Debug("Prepared messages", "filepath", filepath)
+		} else {
+			logging.Debug("Prepared messages", "messages", string(jsonData))
+		}
+
 	}
 	attempts := 0
 	eventChan := make(chan ProviderEvent)

internal/llm/provider/copilot.go

@@ -0,0 +1,671 @@
+package provider
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"time"
+
+	"github.com/openai/openai-go"
+	"github.com/openai/openai-go/option"
+	"github.com/openai/openai-go/shared"
+	"github.com/opencode-ai/opencode/internal/config"
+	"github.com/opencode-ai/opencode/internal/llm/models"
+	toolsPkg "github.com/opencode-ai/opencode/internal/llm/tools"
+	"github.com/opencode-ai/opencode/internal/logging"
+	"github.com/opencode-ai/opencode/internal/message"
+)
+
+type copilotOptions struct {
+	reasoningEffort string
+	extraHeaders    map[string]string
+	bearerToken     string
+}
+
+type CopilotOption func(*copilotOptions)
+
+type copilotClient struct {
+	providerOptions providerClientOptions
+	options         copilotOptions
+	client          openai.Client
+	httpClient      *http.Client
+}
+
+type CopilotClient ProviderClient
+
+// CopilotTokenResponse represents the response from GitHub's token exchange endpoint
+type CopilotTokenResponse struct {
+	Token     string `json:"token"`
+	ExpiresAt int64  `json:"expires_at"`
+}
+
+func (c *copilotClient) isAnthropicModel() bool {
+	for _, modelId := range models.CopilotAnthropicModels {
+		if c.providerOptions.model.ID == modelId {
+			return true
+		}
+	}
+	return false
+}
+
+// loadGitHubToken loads the GitHub OAuth token from the standard GitHub CLI/Copilot locations
+
+// exchangeGitHubToken exchanges a GitHub token for a Copilot bearer token
+func (c *copilotClient) exchangeGitHubToken(githubToken string) (string, error) {
+	req, err := http.NewRequest("GET", "https://api.github.com/copilot_internal/v2/token", nil)
+	if err != nil {
+		return "", fmt.Errorf("failed to create token exchange request: %w", err)
+	}
+
+	req.Header.Set("Authorization", "Token "+githubToken)
+	req.Header.Set("User-Agent", "OpenCode/1.0")
+
+	resp, err := c.httpClient.Do(req)
+	if err != nil {
+		return "", fmt.Errorf("failed to exchange GitHub token: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		body, _ := io.ReadAll(resp.Body)
+		return "", fmt.Errorf("token exchange failed with status %d: %s", resp.StatusCode, string(body))
+	}
+
+	var tokenResp CopilotTokenResponse
+	if err := json.NewDecoder(resp.Body).Decode(&tokenResp); err != nil {
+		return "", fmt.Errorf("failed to decode token response: %w", err)
+	}
+
+	return tokenResp.Token, nil
+}
+
+func newCopilotClient(opts providerClientOptions) CopilotClient {
+	copilotOpts := copilotOptions{
+		reasoningEffort: "medium",
+	}
+	// Apply copilot-specific options
+	for _, o := range opts.copilotOptions {
+		o(&copilotOpts)
+	}
+
+	// Create HTTP client for token exchange
+	httpClient := &http.Client{
+		Timeout: 30 * time.Second,
+	}
+
+	var bearerToken string
+
+	// If bearer token is already provided, use it
+	if copilotOpts.bearerToken != "" {
+		bearerToken = copilotOpts.bearerToken
+	} else {
+		// Try to get GitHub token from multiple sources
+		var githubToken string
+
+		// 1. Environment variable
+		githubToken = os.Getenv("GITHUB_TOKEN")
+
+		// 2. API key from options
+		if githubToken == "" {
+			githubToken = opts.apiKey
+		}
+
+		// 3. Standard GitHub CLI/Copilot locations
+		if githubToken == "" {
+			var err error
+			githubToken, err = config.LoadGitHubToken()
+			if err != nil {
+				logging.Debug("Failed to load GitHub token from standard locations", "error", err)
+			}
+		}
+
+		if githubToken == "" {
+			logging.Error("GitHub token is required for Copilot provider. Set GITHUB_TOKEN environment variable, configure it in opencode.json, or ensure GitHub CLI/Copilot is properly authenticated.")
+			return &copilotClient{
+				providerOptions: opts,
+				options:         copilotOpts,
+				httpClient:      httpClient,
+			}
+		}
+
+		// Create a temporary client for token exchange
+		tempClient := &copilotClient{
+			providerOptions: opts,
+			options:         copilotOpts,
+			httpClient:      httpClient,
+		}
+
+		// Exchange GitHub token for bearer token
+		var err error
+		bearerToken, err = tempClient.exchangeGitHubToken(githubToken)
+		if err != nil {
+			logging.Error("Failed to exchange GitHub token for Copilot bearer token", "error", err)
+			return &copilotClient{
+				providerOptions: opts,
+				options:         copilotOpts,
+				httpClient:      httpClient,
+			}
+		}
+	}
+
+	copilotOpts.bearerToken = bearerToken
+
+	// GitHub Copilot API base URL
+	baseURL := "https://api.githubcopilot.com"
+
+	openaiClientOptions := []option.RequestOption{
+		option.WithBaseURL(baseURL),
+		option.WithAPIKey(bearerToken), // Use bearer token as API key
+	}
+
+	// Add GitHub Copilot specific headers
+	openaiClientOptions = append(openaiClientOptions,
+		option.WithHeader("Editor-Version", "OpenCode/1.0"),
+		option.WithHeader("Editor-Plugin-Version", "OpenCode/1.0"),
+		option.WithHeader("Copilot-Integration-Id", "vscode-chat"),
+	)
+
+	// Add any extra headers
+	if copilotOpts.extraHeaders != nil {
+		for key, value := range copilotOpts.extraHeaders {
+			openaiClientOptions = append(openaiClientOptions, option.WithHeader(key, value))
+		}
+	}
+
+	client := openai.NewClient(openaiClientOptions...)
+	// logging.Debug("Copilot client created", "opts", opts, "copilotOpts", copilotOpts, "model", opts.model)
+	return &copilotClient{
+		providerOptions: opts,
+		options:         copilotOpts,
+		client:          client,
+		httpClient:      httpClient,
+	}
+}
+
+func (c *copilotClient) convertMessages(messages []message.Message) (copilotMessages []openai.ChatCompletionMessageParamUnion) {
+	// Add system message first
+	copilotMessages = append(copilotMessages, openai.SystemMessage(c.providerOptions.systemMessage))
+
+	for _, msg := range messages {
+		switch msg.Role {
+		case message.User:
+			var content []openai.ChatCompletionContentPartUnionParam
+			textBlock := openai.ChatCompletionContentPartTextParam{Text: msg.Content().String()}
+			content = append(content, openai.ChatCompletionContentPartUnionParam{OfText: &textBlock})
+
+			for _, binaryContent := range msg.BinaryContent() {
+				imageURL := openai.ChatCompletionContentPartImageImageURLParam{URL: binaryContent.String(models.ProviderCopilot)}
+				imageBlock := openai.ChatCompletionContentPartImageParam{ImageURL: imageURL}
+				content = append(content, openai.ChatCompletionContentPartUnionParam{OfImageURL: &imageBlock})
+			}
+
+			copilotMessages = append(copilotMessages, openai.UserMessage(content))
+
+		case message.Assistant:
+			assistantMsg := openai.ChatCompletionAssistantMessageParam{
+				Role: "assistant",
+			}
+
+			if msg.Content().String() != "" {
+				assistantMsg.Content = openai.ChatCompletionAssistantMessageParamContentUnion{
+					OfString: openai.String(msg.Content().String()),
+				}
+			}
+
+			if len(msg.ToolCalls()) > 0 {
+				assistantMsg.ToolCalls = make([]openai.ChatCompletionMessageToolCallParam, len(msg.ToolCalls()))
+				for i, call := range msg.ToolCalls() {
+					assistantMsg.ToolCalls[i] = openai.ChatCompletionMessageToolCallParam{
+						ID:   call.ID,
+						Type: "function",
+						Function: openai.ChatCompletionMessageToolCallFunctionParam{
+							Name:      call.Name,
+							Arguments: call.Input,
+						},
+					}
+				}
+			}
+
+			copilotMessages = append(copilotMessages, openai.ChatCompletionMessageParamUnion{
+				OfAssistant: &assistantMsg,
+			})
+
+		case message.Tool:
+			for _, result := range msg.ToolResults() {
+				copilotMessages = append(copilotMessages,
+					openai.ToolMessage(result.Content, result.ToolCallID),
+				)
+			}
+		}
+	}
+
+	return
+}
+
+func (c *copilotClient) convertTools(tools []toolsPkg.BaseTool) []openai.ChatCompletionToolParam {
+	copilotTools := make([]openai.ChatCompletionToolParam, len(tools))
+
+	for i, tool := range tools {
+		info := tool.Info()
+		copilotTools[i] = openai.ChatCompletionToolParam{
+			Function: openai.FunctionDefinitionParam{
+				Name:        info.Name,
+				Description: openai.String(info.Description),
+				Parameters: openai.FunctionParameters{
+					"type":       "object",
+					"properties": info.Parameters,
+					"required":   info.Required,
+				},
+			},
+		}
+	}
+
+	return copilotTools
+}
+
+func (c *copilotClient) finishReason(reason string) message.FinishReason {
+	switch reason {
+	case "stop":
+		return message.FinishReasonEndTurn
+	case "length":
+		return message.FinishReasonMaxTokens
+	case "tool_calls":
+		return message.FinishReasonToolUse
+	default:
+		return message.FinishReasonUnknown
+	}
+}
+
+func (c *copilotClient) preparedParams(messages []openai.ChatCompletionMessageParamUnion, tools []openai.ChatCompletionToolParam) openai.ChatCompletionNewParams {
+	params := openai.ChatCompletionNewParams{
+		Model:    openai.ChatModel(c.providerOptions.model.APIModel),
+		Messages: messages,
+		Tools:    tools,
+	}
+
+	if c.providerOptions.model.CanReason == true {
+		params.MaxCompletionTokens = openai.Int(c.providerOptions.maxTokens)
+		switch c.options.reasoningEffort {
+		case "low":
+			params.ReasoningEffort = shared.ReasoningEffortLow
+		case "medium":
+			params.ReasoningEffort = shared.ReasoningEffortMedium
+		case "high":
+			params.ReasoningEffort = shared.ReasoningEffortHigh
+		default:
+			params.ReasoningEffort = shared.ReasoningEffortMedium
+		}
+	} else {
+		params.MaxTokens = openai.Int(c.providerOptions.maxTokens)
+	}
+
+	return params
+}
+
+func (c *copilotClient) send(ctx context.Context, messages []message.Message, tools []toolsPkg.BaseTool) (response *ProviderResponse, err error) {
+	params := c.preparedParams(c.convertMessages(messages), c.convertTools(tools))
+	cfg := config.Get()
+	var sessionId string
+	requestSeqId := (len(messages) + 1) / 2
+	if cfg.Debug {
+		// jsonData, _ := json.Marshal(params)
+		// logging.Debug("Prepared messages", "messages", string(jsonData))
+		if sid, ok := ctx.Value(toolsPkg.SessionIDContextKey).(string); ok {
+			sessionId = sid
+		}
+		jsonData, _ := json.Marshal(params)
+		if sessionId != "" {
+			filepath := logging.WriteRequestMessageJson(sessionId, requestSeqId, params)
+			logging.Debug("Prepared messages", "filepath", filepath)
+		} else {
+			logging.Debug("Prepared messages", "messages", string(jsonData))
+		}
+	}
+
+	attempts := 0
+	for {
+		attempts++
+		copilotResponse, err := c.client.Chat.Completions.New(
+			ctx,
+			params,
+		)
+
+		// If there is an error we are going to see if we can retry the call
+		if err != nil {
+			retry, after, retryErr := c.shouldRetry(attempts, err)
+			if retryErr != nil {
+				return nil, retryErr
+			}
+			if retry {
+				logging.WarnPersist(fmt.Sprintf("Retrying due to rate limit... attempt %d of %d", attempts, maxRetries), logging.PersistTimeArg, time.Millisecond*time.Duration(after+100))
+				select {
+				case <-ctx.Done():
+					return nil, ctx.Err()
+				case <-time.After(time.Duration(after) * time.Millisecond):
+					continue
+				}
+			}
+			return nil, retryErr
+		}
+
+		content := ""
+		if copilotResponse.Choices[0].Message.Content != "" {
+			content = copilotResponse.Choices[0].Message.Content
+		}
+
+		toolCalls := c.toolCalls(*copilotResponse)
+		finishReason := c.finishReason(string(copilotResponse.Choices[0].FinishReason))
+
+		if len(toolCalls) > 0 {
+			finishReason = message.FinishReasonToolUse
+		}
+
+		return &ProviderResponse{
+			Content:      content,
+			ToolCalls:    toolCalls,
+			Usage:        c.usage(*copilotResponse),
+			FinishReason: finishReason,
+		}, nil
+	}
+}
+
+func (c *copilotClient) stream(ctx context.Context, messages []message.Message, tools []toolsPkg.BaseTool) <-chan ProviderEvent {
+	params := c.preparedParams(c.convertMessages(messages), c.convertTools(tools))
+	params.StreamOptions = openai.ChatCompletionStreamOptionsParam{
+		IncludeUsage: openai.Bool(true),
+	}
+
+	cfg := config.Get()
+	var sessionId string
+	requestSeqId := (len(messages) + 1) / 2
+	if cfg.Debug {
+		if sid, ok := ctx.Value(toolsPkg.SessionIDContextKey).(string); ok {
+			sessionId = sid
+		}
+		jsonData, _ := json.Marshal(params)
+		if sessionId != "" {
+			filepath := logging.WriteRequestMessageJson(sessionId, requestSeqId, params)
+			logging.Debug("Prepared messages", "filepath", filepath)
+		} else {
+			logging.Debug("Prepared messages", "messages", string(jsonData))
+		}
+
+	}
+
+	attempts := 0
+	eventChan := make(chan ProviderEvent)
+
+	go func() {
+		for {
+			attempts++
+			copilotStream := c.client.Chat.Completions.NewStreaming(
+				ctx,
+				params,
+			)
+
+			acc := openai.ChatCompletionAccumulator{}
+			currentContent := ""
+			toolCalls := make([]message.ToolCall, 0)
+
+			var currentToolCallId string
+			var currentToolCall openai.ChatCompletionMessageToolCall
+			var msgToolCalls []openai.ChatCompletionMessageToolCall
+			for copilotStream.Next() {
+				chunk := copilotStream.Current()
+				acc.AddChunk(chunk)
+
+				if cfg.Debug {
+					logging.AppendToStreamSessionLogJson(sessionId, requestSeqId, chunk)
+				}
+
+				for _, choice := range chunk.Choices {
+					if choice.Delta.Content != "" {
+						eventChan <- ProviderEvent{
+							Type:    EventContentDelta,
+							Content: choice.Delta.Content,
+						}
+						currentContent += choice.Delta.Content
+					}
+				}
+
+				if c.isAnthropicModel() {
+					// Monkeypatch adapter for Sonnet-4 multi-tool use
+					for _, choice := range chunk.Choices {
+						if choice.Delta.ToolCalls != nil && len(choice.Delta.ToolCalls) > 0 {
+							toolCall := choice.Delta.ToolCalls[0]
+							// Detect tool use start
+							if currentToolCallId == "" {
+								if toolCall.ID != "" {
+									currentToolCallId = toolCall.ID
+									currentToolCall = openai.ChatCompletionMessageToolCall{
+										ID:   toolCall.ID,
+										Type: "function",
+										Function: openai.ChatCompletionMessageToolCallFunction{
+											Name:      toolCall.Function.Name,
+											Arguments: toolCall.Function.Arguments,
+										},
+									}
+								}
+							} else {
+								// Delta tool use
+								if toolCall.ID == "" {
+									currentToolCall.Function.Arguments += toolCall.Function.Arguments
+								} else {
+									// Detect new tool use
+									if toolCall.ID != currentToolCallId {
+										msgToolCalls = append(msgToolCalls, currentToolCall)
+										currentToolCallId = toolCall.ID
+										currentToolCall = openai.ChatCompletionMessageToolCall{
+											ID:   toolCall.ID,
+											Type: "function",
+											Function: openai.ChatCompletionMessageToolCallFunction{
+												Name:      toolCall.Function.Name,
+												Arguments: toolCall.Function.Arguments,
+											},
+										}
+									}
+								}
+							}
+						}
+						if choice.FinishReason == "tool_calls" {
+							msgToolCalls = append(msgToolCalls, currentToolCall)
+							acc.ChatCompletion.Choices[0].Message.ToolCalls = msgToolCalls
+						}
+					}
+				}
+			}
+
+			err := copilotStream.Err()
+			if err == nil || errors.Is(err, io.EOF) {
+				if cfg.Debug {
+					respFilepath := logging.WriteChatResponseJson(sessionId, requestSeqId, acc.ChatCompletion)
+					logging.Debug("Chat completion response", "filepath", respFilepath)
+				}
+				// Stream completed successfully
+				finishReason := c.finishReason(string(acc.ChatCompletion.Choices[0].FinishReason))
+				if len(acc.ChatCompletion.Choices[0].Message.ToolCalls) > 0 {
+					toolCalls = append(toolCalls, c.toolCalls(acc.ChatCompletion)...)
+				}
+				if len(toolCalls) > 0 {
+					finishReason = message.FinishReasonToolUse
+				}
+
+				eventChan <- ProviderEvent{
+					Type: EventComplete,
+					Response: &ProviderResponse{
+						Content:      currentContent,
+						ToolCalls:    toolCalls,
+						Usage:        c.usage(acc.ChatCompletion),
+						FinishReason: finishReason,
+					},
+				}
+				close(eventChan)
+				return
+			}
+
+			// If there is an error we are going to see if we can retry the call
+			retry, after, retryErr := c.shouldRetry(attempts, err)
+			if retryErr != nil {
+				eventChan <- ProviderEvent{Type: EventError, Error: retryErr}
+				close(eventChan)
+				return
+			}
+			// shouldRetry is not catching the max retries...
+			// TODO: Figure out why
+			if attempts > maxRetries {
+				logging.Warn("Maximum retry attempts reached for rate limit", "attempts", attempts, "max_retries", maxRetries)
+				retry = false
+			}
+			if retry {
+				logging.WarnPersist(fmt.Sprintf("Retrying due to rate limit... attempt %d of %d (paused for %d ms)", attempts, maxRetries, after), logging.PersistTimeArg, time.Millisecond*time.Duration(after+100))
+				select {
+				case <-ctx.Done():
+					// context cancelled
+					if ctx.Err() == nil {
+						eventChan <- ProviderEvent{Type: EventError, Error: ctx.Err()}
+					}
+					close(eventChan)
+					return
+				case <-time.After(time.Duration(after) * time.Millisecond):
+					continue
+				}
+			}
+			eventChan <- ProviderEvent{Type: EventError, Error: retryErr}
+			close(eventChan)
+			return
+		}
+	}()
+
+	return eventChan
+}
+
+func (c *copilotClient) shouldRetry(attempts int, err error) (bool, int64, error) {
+	var apierr *openai.Error
+	if !errors.As(err, &apierr) {
+		return false, 0, err
+	}
+
+	// Check for token expiration (401 Unauthorized)
+	if apierr.StatusCode == 401 {
+		// Try to refresh the bearer token
+		var githubToken string
+
+		// 1. Environment variable
+		githubToken = os.Getenv("GITHUB_TOKEN")
+
+		// 2. API key from options
+		if githubToken == "" {
+			githubToken = c.providerOptions.apiKey
+		}
+
+		// 3. Standard GitHub CLI/Copilot locations
+		if githubToken == "" {
+			var err error
+			githubToken, err = config.LoadGitHubToken()
+			if err != nil {
+				logging.Debug("Failed to load GitHub token from standard locations during retry", "error", err)
+			}
+		}
+
+		if githubToken != "" {
+			newBearerToken, tokenErr := c.exchangeGitHubToken(githubToken)
+			if tokenErr == nil {
+				c.options.bearerToken = newBearerToken
+				// Update the client with the new token
+				// Note: This is a simplified approach. In a production system,
+				// you might want to recreate the entire client with the new token
+				logging.Info("Refreshed Copilot bearer token")
+				return true, 1000, nil // Retry immediately with new token
+			}
+			logging.Error("Failed to refresh Copilot bearer token", "error", tokenErr)
+		}
+		return false, 0, fmt.Errorf("authentication failed: %w", err)
+	}
+	logging.Debug("Copilot API Error", "status", apierr.StatusCode, "headers", apierr.Response.Header, "body", apierr.RawJSON())
+
+	if apierr.StatusCode != 429 && apierr.StatusCode != 500 {
+		return false, 0, err
+	}
+
+	if apierr.StatusCode == 500 {
+		logging.Warn("Copilot API returned 500 error, retrying", "error", err)
+	}
+
+	if attempts > maxRetries {
+		return false, 0, fmt.Errorf("maximum retry attempts reached for rate limit: %d retries", maxRetries)
+	}
+
+	retryMs := 0
+	retryAfterValues := apierr.Response.Header.Values("Retry-After")
+
+	backoffMs := 2000 * (1 << (attempts - 1))
+	jitterMs := int(float64(backoffMs) * 0.2)
+	retryMs = backoffMs + jitterMs
+	if len(retryAfterValues) > 0 {
+		if _, err := fmt.Sscanf(retryAfterValues[0], "%d", &retryMs); err == nil {
+			retryMs = retryMs * 1000
+		}
+	}
+	return true, int64(retryMs), nil
+}
+
+func (c *copilotClient) toolCalls(completion openai.ChatCompletion) []message.ToolCall {
+	var toolCalls []message.ToolCall
+
+	if len(completion.Choices) > 0 && len(completion.Choices[0].Message.ToolCalls) > 0 {
+		for _, call := range completion.Choices[0].Message.ToolCalls {
+			toolCall := message.ToolCall{
+				ID:       call.ID,
+				Name:     call.Function.Name,
+				Input:    call.Function.Arguments,
+				Type:     "function",
+				Finished: true,
+			}
+			toolCalls = append(toolCalls, toolCall)
+		}
+	}
+
+	return toolCalls
+}
+
+func (c *copilotClient) usage(completion openai.ChatCompletion) TokenUsage {
+	cachedTokens := completion.Usage.PromptTokensDetails.CachedTokens
+	inputTokens := completion.Usage.PromptTokens - cachedTokens
+
+	return TokenUsage{
+		InputTokens:         inputTokens,
+		OutputTokens:        completion.Usage.CompletionTokens,
+		CacheCreationTokens: 0, // GitHub Copilot doesn't provide this directly
+		CacheReadTokens:     cachedTokens,
+	}
+}
+
+func WithCopilotReasoningEffort(effort string) CopilotOption {
+	return func(options *copilotOptions) {
+		defaultReasoningEffort := "medium"
+		switch effort {
+		case "low", "medium", "high":
+			defaultReasoningEffort = effort
+		default:
+			logging.Warn("Invalid reasoning effort, using default: medium")
+		}
+		options.reasoningEffort = defaultReasoningEffort
+	}
+}
+
+func WithCopilotExtraHeaders(headers map[string]string) CopilotOption {
+	return func(options *copilotOptions) {
+		options.extraHeaders = headers
+	}
+}
+
+func WithCopilotBearerToken(bearerToken string) CopilotOption {
+	return func(options *copilotOptions) {
+		options.bearerToken = bearerToken
+	}
+}
+

internal/llm/provider/provider.go

@@ -68,6 +68,7 @@ type providerClientOptions struct {
 	openaiOptions    []OpenAIOption
 	geminiOptions    []GeminiOption
 	bedrockOptions   []BedrockOption
+	copilotOptions   []CopilotOption
 }
 
 type ProviderClientOption func(*providerClientOptions)
@@ -88,6 +89,11 @@ func NewProvider(providerName models.ModelProvider, opts ...ProviderClientOption
 		o(&clientOptions)
 	}
 	switch providerName {
+	case models.ProviderCopilot:
+		return &baseProvider[CopilotClient]{
+			options: clientOptions,
+			client:  newCopilotClient(clientOptions),
+		}, nil
 	case models.ProviderAnthropic:
 		return &baseProvider[AnthropicClient]{
 			options: clientOptions,
@@ -233,3 +239,9 @@ func WithBedrockOptions(bedrockOptions ...BedrockOption) ProviderClientOption {
 		options.bedrockOptions = bedrockOptions
 	}
 }
+
+func WithCopilotOptions(copilotOptions ...CopilotOption) ProviderClientOption {
+	return func(options *providerClientOptions) {
+		options.copilotOptions = copilotOptions
+	}
+}

internal/llm/tools/view.go

@@ -11,6 +11,7 @@ import (
 	"strings"
 
 	"github.com/opencode-ai/opencode/internal/config"
+	"github.com/opencode-ai/opencode/internal/logging"
 	"github.com/opencode-ai/opencode/internal/lsp"
 )
 
@@ -97,6 +98,7 @@ func (v *viewTool) Info() ToolInfo {
 // Run implements Tool.
 func (v *viewTool) Run(ctx context.Context, call ToolCall) (ToolResponse, error) {
 	var params ViewParams
+	logging.Debug("view tool params", "params", call.Input)
 	if err := json.Unmarshal([]byte(call.Input), &params); err != nil {
 		return NewTextErrorResponse(fmt.Sprintf("error parsing parameters: %s", err)), nil
 	}

internal/logging/logger.go

@@ -4,16 +4,33 @@ import (
 	"fmt"
 	"log/slog"
 	"os"
+	// "path/filepath"
+	"encoding/json"
+	"runtime"
 	"runtime/debug"
+	"sync"
 	"time"
 )
 
+func getCaller() string {
+	var caller string
+	if _, file, line, ok := runtime.Caller(2); ok {
+		// caller = fmt.Sprintf("%s:%d", filepath.Base(file), line)
+		caller = fmt.Sprintf("%s:%d", file, line)
+	} else {
+		caller = "unknown"
+	}
+	return caller
+}
 func Info(msg string, args ...any) {
-	slog.Info(msg, args...)
+	source := getCaller()
+	slog.Info(msg, append([]any{"source", source}, args...)...)
 }
 
 func Debug(msg string, args ...any) {
-	slog.Debug(msg, args...)
+	// slog.Debug(msg, args...)
+	source := getCaller()
+	slog.Debug(msg, append([]any{"source", source}, args...)...)
 }
 
 func Warn(msg string, args ...any) {
@@ -76,3 +93,115 @@ func RecoverPanic(name string, cleanup func()) {
 		}
 	}
 }
+
+// Message Logging for Debug
+var MessageDir string
+
+func GetSessionPrefix(sessionId string) string {
+	return sessionId[:8]
+}
+
+var sessionLogMutex sync.Mutex
+
+func AppendToSessionLogFile(sessionId string, filename string, content string) string {
+	if MessageDir == "" || sessionId == "" {
+		return ""
+	}
+	sessionPrefix := GetSessionPrefix(sessionId)
+
+	sessionLogMutex.Lock()
+	defer sessionLogMutex.Unlock()
+
+	sessionPath := fmt.Sprintf("%s/%s", MessageDir, sessionPrefix)
+	if _, err := os.Stat(sessionPath); os.IsNotExist(err) {
+		if err := os.MkdirAll(sessionPath, 0o766); err != nil {
+			Error("Failed to create session directory", "dirpath", sessionPath, "error", err)
+			return ""
+		}
+	}
+
+	filePath := fmt.Sprintf("%s/%s", sessionPath, filename)
+
+	f, err := os.OpenFile(filePath, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0644)
+	if err != nil {
+		Error("Failed to open session log file", "filepath", filePath, "error", err)
+		return ""
+	}
+	defer f.Close()
+
+	// Append chunk to file
+	_, err = f.WriteString(content)
+	if err != nil {
+		Error("Failed to write chunk to session log file", "filepath", filePath, "error", err)
+		return ""
+	}
+	return filePath
+}
+
+func WriteRequestMessageJson(sessionId string, requestSeqId int, message any) string {
+	if MessageDir == "" || sessionId == "" || requestSeqId <= 0 {
+		return ""
+	}
+	msgJson, err := json.Marshal(message)
+	if err != nil {
+		Error("Failed to marshal message", "session_id", sessionId, "request_seq_id", requestSeqId, "error", err)
+		return ""
+	}
+	return WriteRequestMessage(sessionId, requestSeqId, string(msgJson))
+}
+
+func WriteRequestMessage(sessionId string, requestSeqId int, message string) string {
+	if MessageDir == "" || sessionId == "" || requestSeqId <= 0 {
+		return ""
+	}
+	filename := fmt.Sprintf("%d_request.json", requestSeqId)
+
+	return AppendToSessionLogFile(sessionId, filename, message)
+}
+
+func AppendToStreamSessionLogJson(sessionId string, requestSeqId int, jsonableChunk any) string {
+	if MessageDir == "" || sessionId == "" || requestSeqId <= 0 {
+		return ""
+	}
+	chunkJson, err := json.Marshal(jsonableChunk)
+	if err != nil {
+		Error("Failed to marshal message", "session_id", sessionId, "request_seq_id", requestSeqId, "error", err)
+		return ""
+	}
+	return AppendToStreamSessionLog(sessionId, requestSeqId, string(chunkJson))
+}
+
+func AppendToStreamSessionLog(sessionId string, requestSeqId int, chunk string) string {
+	if MessageDir == "" || sessionId == "" || requestSeqId <= 0 {
+		return ""
+	}
+	filename := fmt.Sprintf("%d_response_stream.log", requestSeqId)
+	return AppendToSessionLogFile(sessionId, filename, chunk)
+}
+
+func WriteChatResponseJson(sessionId string, requestSeqId int, response any) string {
+	if MessageDir == "" || sessionId == "" || requestSeqId <= 0 {
+		return ""
+	}
+	responseJson, err := json.Marshal(response)
+	if err != nil {
+		Error("Failed to marshal response", "session_id", sessionId, "request_seq_id", requestSeqId, "error", err)
+		return ""
+	}
+	filename := fmt.Sprintf("%d_response.json", requestSeqId)
+
+	return AppendToSessionLogFile(sessionId, filename, string(responseJson))
+}
+
+func WriteToolResultsJson(sessionId string, requestSeqId int, toolResults any) string {
+	if MessageDir == "" || sessionId == "" || requestSeqId <= 0 {
+		return ""
+	}
+	toolResultsJson, err := json.Marshal(toolResults)
+	if err != nil {
+		Error("Failed to marshal tool results", "session_id", sessionId, "request_seq_id", requestSeqId, "error", err)
+		return ""
+	}
+	filename := fmt.Sprintf("%d_tool_results.json", requestSeqId)
+	return AppendToSessionLogFile(sessionId, filename, string(toolResultsJson))
+}

internal/logging/writer.go

@@ -45,6 +45,7 @@ type writer struct{}
 
 func (w *writer) Write(p []byte) (int, error) {
 	d := logfmt.NewDecoder(bytes.NewReader(p))
+
 	for d.ScanRecord() {
 		msg := LogMessage{
 			ID:   fmt.Sprintf("%d", time.Now().UnixNano()),

opencode-schema.json

@@ -77,7 +77,18 @@
             "openrouter.o4-mini",
             "openrouter.claude-3.5-haiku",
             "claude-4-opus",
-            "openrouter.o1-pro"
+            "openrouter.o1-pro",
+            "copilot.gpt-4o",
+            "copilot.gpt-4o-mini",
+            "copilot.gpt-4.1",
+            "copilot.claude-3.5-sonnet",
+            "copilot.claude-3.7-sonnet",
+            "copilot.claude-sonnet-4",
+            "copilot.o1",
+            "copilot.o3-mini",
+            "copilot.o4-mini",
+            "copilot.gemini-2.0-flash",
+            "copilot.gemini-2.5-pro"
           ],
           "type": "string"
         },
@@ -176,7 +187,18 @@
               "openrouter.o4-mini",
               "openrouter.claude-3.5-haiku",
               "claude-4-opus",
-              "openrouter.o1-pro"
+              "openrouter.o1-pro",
+              "copilot.gpt-4o",
+              "copilot.gpt-4o-mini",
+              "copilot.gpt-4.1",
+              "copilot.claude-3.5-sonnet",
+              "copilot.claude-3.7-sonnet",
+              "copilot.claude-sonnet-4",
+              "copilot.o1",
+              "copilot.o3-mini",
+              "copilot.o4-mini",
+              "copilot.gemini-2.0-flash",
+              "copilot.gemini-2.5-pro"
             ],
             "type": "string"
           },
@@ -360,7 +382,8 @@
               "openrouter",
               "bedrock",
               "azure",
-              "vertexai"
+              "vertexai",
+              "copilot"
             ],
             "type": "string"
           }