feat: 为 codeagent-wrapper 添加 Gemini 模型参数支持

新增功能：
- 添加 --gemini-model 参数，支持指定 Gemini 模型（如 gemini-2.5-flash）
- 支持 GEMINI_MODEL 环境变量配置，CLI 参数优先级高于环境变量
- 模型参数自动插入到 gemini CLI 调用的正确位置（-m 参数在其他参数之前）
- 添加详细的日志记录和警告提示
- 更新帮助文档，说明参数用法和示例

技术实现：
- Config 结构体新增 GeminiModel 字段
- parseArgs() 函数支持 --gemini-model 和 --gemini-model=<value> 两种语法
- buildGeminiArgs() 函数在构建参数时优先插入模型参数
- 添加跨后端和并行模式的参数验证警告

版本更新：v5.7.1 → v5.7.2

codeagent-wrapper/backend.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"os"
 	"path/filepath"
+	"strings"
 )
 
 // Backend defines the contract for invoking different AI CLI backends.
@@ -120,7 +121,16 @@ func buildGeminiArgs(cfg *Config, targetArg string) []string {
 	if cfg == nil {
 		return nil
 	}
-	args := []string{"--output-format", "stream-json", "-y"}
+
+	args := []string{}
+
+	// Add model parameter first (if specified)
+	if model := strings.TrimSpace(cfg.GeminiModel); model != "" {
+		args = append(args, "-m", model)
+	}
+
+	// Existing args
+	args = append(args, "-o", "stream-json", "-y")
 
 	if cfg.Mode == "resume" {
 		if cfg.SessionID != "" {

codeagent-wrapper/config.go

@@ -20,6 +20,7 @@ type Config struct {
 	Backend            string
 	SkipPermissions    bool
 	MaxParallelWorkers int
+	GeminiModel        string // Gemini model name (empty = use default)
 }
 
 // ParallelConfig defines the JSON schema for parallel execution
@@ -197,6 +198,9 @@ func parseArgs() (*Config, error) {
 		return nil, fmt.Errorf("task required")
 	}
 
+	// Read environment variable (lowest precedence)
+	geminiModel := strings.TrimSpace(os.Getenv("GEMINI_MODEL"))
+
 	backendName := defaultBackendName
 	skipPermissions := envFlagEnabled("CODEAGENT_SKIP_PERMISSIONS")
 	filtered := make([]string, 0, len(args))
@@ -220,6 +224,24 @@ func parseArgs() (*Config, error) {
 			}
 			backendName = value
 			continue
+		case arg == "--gemini-model":
+			if i+1 >= len(args) {
+				return nil, fmt.Errorf("--gemini-model flag requires a non-empty model name")
+			}
+			value := strings.TrimSpace(args[i+1])
+			if value == "" {
+				return nil, fmt.Errorf("--gemini-model flag requires a non-empty model name")
+			}
+			geminiModel = value
+			i++
+			continue
+		case strings.HasPrefix(arg, "--gemini-model="):
+			value := strings.TrimSpace(strings.TrimPrefix(arg, "--gemini-model="))
+			if value == "" {
+				return nil, fmt.Errorf("--gemini-model flag requires a non-empty model name")
+			}
+			geminiModel = value
+			continue
 		case arg == "--skip-permissions", arg == "--dangerously-skip-permissions":
 			skipPermissions = true
 			continue
@@ -238,7 +260,7 @@ func parseArgs() (*Config, error) {
 	}
 	args = filtered
 
-	cfg := &Config{WorkDir: defaultWorkdir, Backend: backendName, SkipPermissions: skipPermissions}
+	cfg := &Config{WorkDir: defaultWorkdir, Backend: backendName, SkipPermissions: skipPermissions, GeminiModel: geminiModel}
 	cfg.MaxParallelWorkers = resolveMaxParallelWorkers()
 
 	if args[0] == "resume" {

codeagent-wrapper/main.go

@@ -14,7 +14,7 @@ import (
 )
 
 const (
-	version               = "5.7.1"
+	version               = "5.7.2"
 	defaultWorkdir        = "."
 	defaultTimeout        = 7200 // seconds (2 hours)
 	defaultCoverageTarget = 90.0
@@ -197,6 +197,9 @@ func run() (exitCode int) {
 			fullOutput := false
 			var extras []string
 
+			// Check for gemini-model in parallel mode
+			geminiModelInParallel := false
+
 			for i := 0; i < len(args); i++ {
 				arg := args[i]
 				switch {
@@ -218,11 +221,19 @@ func run() (exitCode int) {
 						return 1
 					}
 					backendName = value
+				case arg == "--gemini-model" || strings.HasPrefix(arg, "--gemini-model="):
+					geminiModelInParallel = true
+					continue
 				default:
 					extras = append(extras, arg)
 				}
 			}
 
+			// Warn about unsupported parameter
+			if geminiModelInParallel {
+				logWarn("--gemini-model parameter is not supported in parallel mode")
+			}
+
 			if len(extras) > 0 {
 				fmt.Fprintln(os.Stderr, "ERROR: --parallel reads its task configuration from stdin; only --backend and --full-output are allowed.")
 				fmt.Fprintln(os.Stderr, "Usage examples:")
@@ -322,6 +333,14 @@ func run() (exitCode int) {
 	}
 	logInfo(fmt.Sprintf("Parsed args: mode=%s, task_len=%d, backend=%s", cfg.Mode, len(cfg.Task), cfg.Backend))
 
+	// Log environment variable usage
+	if cfg.GeminiModel != "" {
+		envModel := strings.TrimSpace(os.Getenv("GEMINI_MODEL"))
+		if envModel != "" && envModel == cfg.GeminiModel {
+			logInfo(fmt.Sprintf("Gemini model from env: %s", cfg.GeminiModel))
+		}
+	}
+
 	backend, err := selectBackendFn(cfg.Backend)
 	if err != nil {
 		logError(err.Error())
@@ -342,6 +361,16 @@ func run() (exitCode int) {
 	}
 	logInfo(fmt.Sprintf("Selected backend: %s", backend.Name()))
 
+	// Log model parameter usage
+	if cfg.GeminiModel != "" && cfg.Backend == "gemini" {
+		logInfo(fmt.Sprintf("Using Gemini model: %s", cfg.GeminiModel))
+	}
+
+	// Warn if model parameter used with non-gemini backend
+	if cfg.GeminiModel != "" && cfg.Backend != "gemini" {
+		logWarn("--gemini-model parameter is only effective with --backend gemini")
+	}
+
 	timeoutSec := resolveTimeout()
 	logInfo(fmt.Sprintf("Timeout: %ds", timeoutSec))
 	cfg.Timeout = timeoutSec
@@ -532,6 +561,10 @@ Parallel mode examples:
 Options:
     --lite, -L            Lite mode: disable Web UI, faster response
     --backend <name>      Select backend (codex, gemini, claude)
+    --gemini-model <name> Specify Gemini model (gemini backend only)
+                          Can also be set via GEMINI_MODEL environment variable
+                          CLI parameter takes precedence over environment variable
+                          Examples: gemini-2.5-flash, gemini-1.5-pro
 
 Environment Variables:
     CODEX_TIMEOUT              Timeout in milliseconds (default: 7200000)