Add support for multiple providers

internal/llm/llm.go

@@ -20,8 +20,6 @@ import (
 type Config struct {
 	// Key is the API key for authentication.
 	Key string `yaml:"key"`
-	// Model is the model identifier.
-	Model string `yaml:"model"`
 	// SystemMessage is prepended to all conversations.
 	SystemMessage string `yaml:"system_message"`
 	// Timeout is the maximum duration for a query (e.g., "5m").
@@ -33,9 +31,6 @@ type Config struct {
 
 // Validate checks that required configuration values are present and valid.
 func (cfg Config) Validate() error {
-	if cfg.Model == "" {
-		return fmt.Errorf("missing model")
-	}
 	if cfg.Timeout != "" {
 		if _, err := time.ParseDuration(cfg.Timeout); err != nil {
 			return fmt.Errorf("invalid timeout: %w", err)
@@ -51,7 +46,6 @@ func (cfg Config) Validate() error {
 type Client struct {
 	client        *openai.Client
 	log           *slog.Logger
-	model         string
 	registry      *tool.Registry
 	systemMessage string
 	timeout       time.Duration
@@ -71,7 +65,6 @@ func NewClient(
 
 	llm := &Client{
 		log:           log,
-		model:         cfg.Model,
 		systemMessage: cfg.SystemMessage,
 		registry:      registry,
 	}
@@ -115,17 +108,11 @@ func (c *Client) ListModels(ctx context.Context) ([]openai.Model, error) {
 	return res.Models, nil
 }
 
-// DefaultModel returns the configured default model.
-func (c *Client) DefaultModel() string {
-	return c.model
-}
-
 // ErrMaxIterations is returned when the agent loop exceeds the configured
 // maximum number of iterations.
 var ErrMaxIterations = fmt.Errorf("max iterations exceeded")
 
 // Query sends messages to the LLM using the specified model.
-// If model is empty, uses the default configured model.
 // If systemMessage is non-empty, it overrides the configured system message.
 // maxIterations caps the number of agent loop iterations; a value of 0
 // means unlimited (no cap).
@@ -141,11 +128,6 @@ func (c *Client) Query(
 	ctx, cancel := context.WithTimeout(ctx, c.timeout)
 	defer cancel()
 
-	// Fallback to the default model.
-	if model == "" {
-		model = c.model
-	}
-
 	// Use per-request system message if provided, otherwise fall back to config.
 	effectiveMessage := c.systemMessage
 	if systemMessage != "" {
@@ -273,11 +255,6 @@ func (c *Client) QueryStream(
 	ctx, cancel := context.WithTimeout(ctx, c.timeout)
 	defer cancel()
 
-	// Fallback to the default model.
-	if model == "" {
-		model = c.model
-	}
-
 	// Use per-request system message if provided, otherwise fall back to config.
 	effectiveMessage := c.systemMessage
 	if systemMessage != "" {
@@ -412,11 +389,6 @@ func (c *Client) QueryStream(
 				result = fmt.Sprintf(
 					`{"ok": false, "error": %q}`, err,
 				)
-			} else {
-				c.log.Info(
-					"called tool",
-					slog.String("name", tc.Function.Name),
-				)
 			}
 			// Content cannot be empty.
 			if strings.TrimSpace(result) == "" {