diff --git a/cmd/fetch_antigravity_models/main.go b/cmd/fetch_antigravity_models/main.go
new file mode 100644
index 00000000..0cf45d3b
--- /dev/null
+++ b/cmd/fetch_antigravity_models/main.go
@@ -0,0 +1,275 @@
+// Command fetch_antigravity_models connects to the Antigravity API using the
+// stored auth credentials and saves the dynamically fetched model list to a
+// JSON file for inspection or offline use.
+//
+// Usage:
+//
+//	go run ./cmd/fetch_antigravity_models [flags]
+//
+// Flags:
+//
+//	--auths-dir <path>  Directory containing auth JSON files (default: "auths")
+//	--output    <path>  Output JSON file path             (default: "antigravity_models.json")
+//	--pretty            Pretty-print the output JSON      (default: true)
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"flag"
+	"fmt"
+	"io"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	"github.com/router-for-me/CLIProxyAPI/v6/internal/logging"
+	sdkauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/auth"
+	coreauth "github.com/router-for-me/CLIProxyAPI/v6/sdk/cliproxy/auth"
+	"github.com/router-for-me/CLIProxyAPI/v6/sdk/proxyutil"
+	log "github.com/sirupsen/logrus"
+	"github.com/tidwall/gjson"
+)
+
+const (
+	antigravityBaseURLDaily        = "https://daily-cloudcode-pa.googleapis.com"
+	antigravitySandboxBaseURLDaily = "https://daily-cloudcode-pa.sandbox.googleapis.com"
+	antigravityBaseURLProd         = "https://cloudcode-pa.googleapis.com"
+	antigravityModelsPath          = "/v1internal:fetchAvailableModels"
+)
+
+func init() {
+	logging.SetupBaseLogger()
+	log.SetLevel(log.InfoLevel)
+}
+
+// modelOutput wraps the fetched model list with fetch metadata.
+type modelOutput struct {
+	Models []modelEntry `json:"models"`
+}
+
+// modelEntry contains only the fields we want to keep for static model definitions.
+type modelEntry struct {
+	ID                  string `json:"id"`
+	Object              string `json:"object"`
+	OwnedBy             string `json:"owned_by"`
+	Type                string `json:"type"`
+	DisplayName         string `json:"display_name"`
+	Name                string `json:"name"`
+	Description         string `json:"description"`
+	ContextLength       int    `json:"context_length,omitempty"`
+	MaxCompletionTokens int    `json:"max_completion_tokens,omitempty"`
+}
+
+func main() {
+	var authsDir string
+	var outputPath string
+	var pretty bool
+
+	flag.StringVar(&authsDir, "auths-dir", "auths", "Directory containing auth JSON files")
+	flag.StringVar(&outputPath, "output", "antigravity_models.json", "Output JSON file path")
+	flag.BoolVar(&pretty, "pretty", true, "Pretty-print the output JSON")
+	flag.Parse()
+
+	// Resolve relative paths against the working directory.
+	wd, err := os.Getwd()
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: cannot get working directory: %v\n", err)
+		os.Exit(1)
+	}
+	if !filepath.IsAbs(authsDir) {
+		authsDir = filepath.Join(wd, authsDir)
+	}
+	if !filepath.IsAbs(outputPath) {
+		outputPath = filepath.Join(wd, outputPath)
+	}
+
+	fmt.Printf("Scanning auth files in: %s\n", authsDir)
+
+	// Load all auth records from the directory.
+	fileStore := sdkauth.NewFileTokenStore()
+	fileStore.SetBaseDir(authsDir)
+
+	ctx := context.Background()
+	auths, err := fileStore.List(ctx)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: failed to list auth files: %v\n", err)
+		os.Exit(1)
+	}
+	if len(auths) == 0 {
+		fmt.Fprintf(os.Stderr, "error: no auth files found in %s\n", authsDir)
+		os.Exit(1)
+	}
+
+	// Find the first enabled antigravity auth.
+	var chosen *coreauth.Auth
+	for _, a := range auths {
+		if a == nil || a.Disabled {
+			continue
+		}
+		if strings.EqualFold(strings.TrimSpace(a.Provider), "antigravity") {
+			chosen = a
+			break
+		}
+	}
+	if chosen == nil {
+		fmt.Fprintf(os.Stderr, "error: no enabled antigravity auth found in %s\n", authsDir)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Using auth: id=%s label=%s\n", chosen.ID, chosen.Label)
+
+	// Fetch models from the upstream Antigravity API.
+	fmt.Println("Fetching Antigravity model list from upstream...")
+
+	fetchCtx, cancel := context.WithTimeout(ctx, 30*time.Second)
+	defer cancel()
+
+	models := fetchModels(fetchCtx, chosen)
+	if len(models) == 0 {
+		fmt.Fprintln(os.Stderr, "warning: no models returned (API may be unavailable or token expired)")
+	} else {
+		fmt.Printf("Fetched %d models.\n", len(models))
+	}
+
+	// Build the output payload.
+	out := modelOutput{
+		Models: models,
+	}
+
+	// Marshal to JSON.
+	var raw []byte
+	if pretty {
+		raw, err = json.MarshalIndent(out, "", "  ")
+	} else {
+		raw, err = json.Marshal(out)
+	}
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "error: failed to marshal JSON: %v\n", err)
+		os.Exit(1)
+	}
+
+	if err = os.WriteFile(outputPath, raw, 0o644); err != nil {
+		fmt.Fprintf(os.Stderr, "error: failed to write output file %s: %v\n", outputPath, err)
+		os.Exit(1)
+	}
+
+	fmt.Printf("Model list saved to: %s\n", outputPath)
+}
+
+func fetchModels(ctx context.Context, auth *coreauth.Auth) []modelEntry {
+	accessToken := metaStringValue(auth.Metadata, "access_token")
+	if accessToken == "" {
+		fmt.Fprintln(os.Stderr, "error: no access token found in auth")
+		return nil
+	}
+
+	baseURLs := []string{antigravityBaseURLProd, antigravityBaseURLDaily, antigravitySandboxBaseURLDaily}
+
+	for _, baseURL := range baseURLs {
+		modelsURL := baseURL + antigravityModelsPath
+
+		var payload []byte
+		if auth != nil && auth.Metadata != nil {
+			if pid, ok := auth.Metadata["project_id"].(string); ok && strings.TrimSpace(pid) != "" {
+				payload = []byte(fmt.Sprintf(`{"project": "%s"}`, strings.TrimSpace(pid)))
+			}
+		}
+		if len(payload) == 0 {
+			payload = []byte(`{}`)
+		}
+
+		httpReq, errReq := http.NewRequestWithContext(ctx, http.MethodPost, modelsURL, strings.NewReader(string(payload)))
+		if errReq != nil {
+			continue
+		}
+		httpReq.Close = true
+		httpReq.Header.Set("Content-Type", "application/json")
+		httpReq.Header.Set("Authorization", "Bearer "+accessToken)
+		httpReq.Header.Set("User-Agent", "antigravity/1.19.6 darwin/arm64")
+
+		httpClient := &http.Client{Timeout: 30 * time.Second}
+		if transport, _, errProxy := proxyutil.BuildHTTPTransport(auth.ProxyURL); errProxy == nil && transport != nil {
+			httpClient.Transport = transport
+		}
+		httpResp, errDo := httpClient.Do(httpReq)
+		if errDo != nil {
+			continue
+		}
+
+		bodyBytes, errRead := io.ReadAll(httpResp.Body)
+		httpResp.Body.Close()
+		if errRead != nil {
+			continue
+		}
+
+		if httpResp.StatusCode < http.StatusOK || httpResp.StatusCode >= http.StatusMultipleChoices {
+			continue
+		}
+
+		result := gjson.GetBytes(bodyBytes, "models")
+		if !result.Exists() {
+			continue
+		}
+
+		var models []modelEntry
+
+		for originalName, modelData := range result.Map() {
+			modelID := strings.TrimSpace(originalName)
+			if modelID == "" {
+				continue
+			}
+			// Skip internal/experimental models
+			switch modelID {
+			case "chat_20706", "chat_23310", "tab_flash_lite_preview", "tab_jump_flash_lite_preview", "gemini-2.5-flash-thinking", "gemini-2.5-pro":
+				continue
+			}
+
+			displayName := modelData.Get("displayName").String()
+			if displayName == "" {
+				displayName = modelID
+			}
+
+			entry := modelEntry{
+				ID:          modelID,
+				Object:      "model",
+				OwnedBy:     "antigravity",
+				Type:        "antigravity",
+				DisplayName: displayName,
+				Name:        modelID,
+				Description: displayName,
+			}
+
+			if maxTok := modelData.Get("maxTokens").Int(); maxTok > 0 {
+				entry.ContextLength = int(maxTok)
+			}
+			if maxOut := modelData.Get("maxOutputTokens").Int(); maxOut > 0 {
+				entry.MaxCompletionTokens = int(maxOut)
+			}
+
+			models = append(models, entry)
+		}
+
+		return models
+	}
+
+	return nil
+}
+
+func metaStringValue(m map[string]interface{}, key string) string {
+	if m == nil {
+		return ""
+	}
+	v, ok := m[key]
+	if !ok {
+		return ""
+	}
+	switch val := v.(type) {
+	case string:
+		return val
+	default:
+		return ""
+	}
+}