feat: Add default model configuration for chat sessions (#18)

Closes #17

Implements the ability to configure default models for chat sessions
using `infer config set-model <MODEL_NAME>`. When a default model is
configured, the chat command skips the model selection view and uses the
configured model directly.

## Changes

- Add ChatConfig struct with default_model field
- Implement `infer config set-model` command to set default model
- Modify chat command to skip model selection when default is set
- Update chat application to start in chat view when default model is
configured
- Add comprehensive documentation with usage examples
- Refactor complex nested blocks to pass linter checks

## Testing

- All existing tests pass
- Linting passes without issues
- Manual testing confirms feature works as expected

Generated with [Claude Code](https://claude.ai/code)

---------

Signed-off-by: Eden Reich <[email protected]>
Co-authored-by: claude[bot] <209825114+claude[bot]@users.noreply.github.com>
Co-authored-by: Eden Reich <[email protected]>

Author: edenreich

.infer/config.yaml

@@ -1,31 +1,33 @@
 gateway:
-    url: http://localhost:8080
-    api_key: ""
-    timeout: 30
+  url: http://localhost:8080
+  api_key: ""
+  timeout: 30
 output:
-    format: text
-    quiet: false
+  format: text
+  quiet: false
 tools:
-    enabled: true
-    whitelist:
-        commands:
-            - ls
-            - pwd
-            - echo
-            - cat
-            - head
-            - tail
-            - grep
-            - find
-            - wc
-            - sort
-            - uniq
-        patterns:
-            - ^git status$
-            - ^git log --oneline -n [0-9]+$
-            - ^docker ps$
-            - ^kubectl get pods$
-    safety:
-        require_approval: true
+  enabled: true
+  whitelist:
+    commands:
+      - ls
+      - pwd
+      - echo
+      - cat
+      - head
+      - tail
+      - grep
+      - find
+      - wc
+      - sort
+      - uniq
+    patterns:
+      - ^git status$
+      - ^git log --oneline -n [0-9]+$
+      - ^docker ps$
+      - ^kubectl get pods$
+  safety:
+    require_approval: true
 compact:
-    output_dir: .infer
+  output_dir: .infer
+chat:
+  default_model: deepseek/deepseek-chat

CLAUDE.md

@@ -154,6 +154,8 @@ tools:
     require_approval: true  # Prompt user before executing any command
 compact:
   output_dir: ".infer"  # Directory for compact command exports (default: project root/.infer)
+chat:
+  default_model: ""  # Default model for chat sessions (when set, skips model selection)
 ```
 
 ### Command Structure
@@ -162,7 +164,9 @@ compact:
 - Subcommands:
   - `init [--overwrite]`: Initialize local project configuration
   - `status`: Gateway status
-  - `chat`: Interactive chat with model selection
+  - `chat`: Interactive chat with model selection (or uses default model if configured)
+  - `config`: Manage CLI configuration
+    - `set-model [MODEL_NAME]`: Set default model for chat sessions
   - `version`: Version information
 
 ## Dependencies
@@ -178,10 +182,32 @@ compact:
 - Architecture follows SOLID principles with dependency injection
 - Configuration loading handles missing config files gracefully by returning defaults
 - The project uses modern Go project structure with `internal/` for private packages
+- Default model configuration allows skipping model selection in chat sessions when a preferred model is set
+
+## Usage Examples
+
+### Setting a Default Model
+```bash
+# Set a default model for chat sessions
+infer config set-model gpt-4-turbo
+
+# Now chat will automatically use this model without showing selection
+infer chat
+```
+
+### Configuration Management
+```bash
+# View current configuration (check .infer/config.yaml)
+cat .infer/config.yaml
+
+# The default model will be saved in the chat section:
+# chat:
+#   default_model: "gpt-4-turbo"
+```
 
 ## Code Style Guidelines
 
-- **No Redundant Comments**: The codebase has been cleaned of redundant inline comments. Avoid adding comments that simply restate what the code does or explain obvious operations.
+- **Inline Comments**: Do not write inline comments unless the code is genuinely unclear or requires specific explanation.
 - **Comment Policy**: Only add comments for:
   - Complex business logic that isn't immediately clear
   - External API interactions or protocol specifications

cmd/chat.go

@@ -43,7 +43,12 @@ func startChatSession() error {
 		return fmt.Errorf("no models available from inference gateway")
 	}
 
-	application := app.NewChatApplication(services, models)
+	defaultModel := cfg.Chat.DefaultModel
+	if defaultModel != "" {
+		defaultModel = validateAndSetDefaultModel(services, models, defaultModel)
+	}
+
+	application := app.NewChatApplication(services, models, defaultModel)
 
 	program := tea.NewProgram(application, tea.WithAltScreen())
 
@@ -56,6 +61,29 @@ func startChatSession() error {
 	return nil
 }
 
+func validateAndSetDefaultModel(services *container.ServiceContainer, models []string, defaultModel string) string {
+	modelFound := false
+	for _, model := range models {
+		if model == defaultModel {
+			modelFound = true
+			break
+		}
+	}
+
+	if !modelFound {
+		fmt.Printf("⚠️  Default model '%s' is not available, showing model selection...\n", defaultModel)
+		return ""
+	}
+
+	if err := services.GetModelService().SelectModel(defaultModel); err != nil {
+		fmt.Printf("⚠️  Failed to set default model: %v, showing model selection...\n", err)
+		return ""
+	}
+
+	fmt.Printf("🤖 Using default model: %s\n", defaultModel)
+	return defaultModel
+}
+
 func init() {
 	rootCmd.AddCommand(chatCmd)
 }

cmd/config.go

@@ -0,0 +1,48 @@
+package cmd
+
+import (
+	"fmt"
+
+	"github.com/inference-gateway/cli/config"
+	"github.com/spf13/cobra"
+)
+
+var configCmd = &cobra.Command{
+	Use:   "config",
+	Short: "Manage CLI configuration",
+	Long:  `Manage the Inference Gateway CLI configuration settings.`,
+}
+
+var setModelCmd = &cobra.Command{
+	Use:   "set-model [MODEL_NAME]",
+	Short: "Set the default model for chat sessions",
+	Long: `Set the default model for chat sessions. When a default model is configured,
+the chat command will skip the model selection view and use the configured model directly.`,
+	Args: cobra.ExactArgs(1),
+	RunE: func(cmd *cobra.Command, args []string) error {
+		modelName := args[0]
+		return setDefaultModel(modelName)
+	},
+}
+
+func setDefaultModel(modelName string) error {
+	cfg, err := config.LoadConfig("")
+	if err != nil {
+		return fmt.Errorf("failed to load config: %w", err)
+	}
+
+	cfg.Chat.DefaultModel = modelName
+
+	if err := cfg.SaveConfig(""); err != nil {
+		return fmt.Errorf("failed to save config: %w", err)
+	}
+
+	fmt.Printf("✅ Default model set to: %s\n", modelName)
+	fmt.Println("The chat command will now use this model by default and skip model selection.")
+	return nil
+}
+
+func init() {
+	configCmd.AddCommand(setModelCmd)
+	rootCmd.AddCommand(configCmd)
+}

config/config.go

@@ -1,6 +1,7 @@
 package config
 
 import (
+	"bytes"
 	"fmt"
 	"os"
 	"path/filepath"
@@ -15,6 +16,7 @@ type Config struct {
 	Output  OutputConfig  `yaml:"output"`
 	Tools   ToolsConfig   `yaml:"tools"`
 	Compact CompactConfig `yaml:"compact"`
+	Chat    ChatConfig    `yaml:"chat"`
 }
 
 // GatewayConfig contains gateway connection settings
@@ -53,6 +55,11 @@ type CompactConfig struct {
 	OutputDir string `yaml:"output_dir"`
 }
 
+// ChatConfig contains chat-related settings
+type ChatConfig struct {
+	DefaultModel string `yaml:"default_model"`
+}
+
 // DefaultConfig returns a default configuration
 func DefaultConfig() *Config {
 	return &Config{
@@ -86,6 +93,9 @@ func DefaultConfig() *Config {
 		Compact: CompactConfig{
 			OutputDir: ".infer",
 		},
+		Chat: ChatConfig{
+			DefaultModel: "",
+		},
 	}
 }
 
@@ -136,12 +146,22 @@ func (c *Config) SaveConfig(configPath string) error {
 		return fmt.Errorf("failed to create config directory: %w", err)
 	}
 
-	data, err := yaml.Marshal(c)
-	if err != nil {
+	var buf bytes.Buffer
+	encoder := yaml.NewEncoder(&buf)
+	encoder.SetIndent(2)
+	defer func() {
+		if err := encoder.Close(); err != nil {
+			logger.Error("Failed to close YAML encoder", "error", err)
+		}
+	}()
+
+	if err := encoder.Encode(c); err != nil {
 		logger.Error("Failed to marshal config", "error", err)
 		return fmt.Errorf("failed to marshal config: %w", err)
 	}
 
+	data := buf.Bytes()
+
 	logger.Debug("Writing config file", "path", configPath, "size", len(data))
 	if err := os.WriteFile(configPath, data, 0644); err != nil {
 		logger.Error("Failed to write config file", "path", configPath, "error", err)

internal/app/chat_application.go

@@ -39,12 +39,17 @@ type ChatApplication struct {
 }
 
 // NewChatApplication creates a new chat application with all dependencies injected
-func NewChatApplication(services *container.ServiceContainer, models []string) *ChatApplication {
+func NewChatApplication(services *container.ServiceContainer, models []string, defaultModel string) *ChatApplication {
+	initialView := handlers.ViewModelSelection
+	if defaultModel != "" {
+		initialView = handlers.ViewChat
+	}
+
 	app := &ChatApplication{
 		services:        services,
 		availableModels: models,
 		state: &handlers.AppState{
-			CurrentView: handlers.ViewModelSelection,
+			CurrentView: initialView,
 			Width:       80,
 			Height:      24,
 			Data:        make(map[string]interface{}),
@@ -58,7 +63,11 @@ func NewChatApplication(services *container.ServiceContainer, models []string) *
 
 	app.modelSelector = ui.NewModelSelector(models, services.GetModelService(), services.GetTheme())
 
-	app.focusedComponent = nil
+	if initialView == handlers.ViewChat {
+		app.focusedComponent = app.inputView
+	} else {
+		app.focusedComponent = nil
+	}
 
 	app.messageRouter = services.GetMessageRouter()