diff --git a/README.md b/README.md
index 299d387..4c9c640 100644
--- a/README.md
+++ b/README.md
@@ -726,7 +726,7 @@ You can also download the binary manually from the release page or build from so
 
 ### Q: Where are credentials stored on Windows?
 
-gitlink-cli uses Windows Credential Manager for secure token storage. If Credential Manager is unavailable, it automatically falls back to file storage (`~/.config/gitlink-cli/credentials`).
+gitlink-cli uses Windows Credential Manager for secure token storage. If Credential Manager is unavailable, it automatically falls back to file storage under the gitlink-cli config directory (`$GITLINK_CONFIG_DIR/credentials` when set, otherwise `~/.config/gitlink-cli/credentials`).
 
 ### Q: Where can I find the full API reference?
 
diff --git a/README.zh-CN.md b/README.zh-CN.md
index a727d59..f26e753 100644
--- a/README.zh-CN.md
+++ b/README.zh-CN.md
@@ -601,7 +601,7 @@ npm install -g @gitlink-ai/cli
 
 ### Q: Windows 上凭证存储在哪里？
 
-gitlink-cli 使用 Windows Credential Manager 安全存储 Token。如果 Credential Manager 不可用，会自动降级到文件存储（`~/.config/gitlink-cli/credentials`）。
+gitlink-cli 使用 Windows Credential Manager 安全存储 Token。如果 Credential Manager 不可用，会自动降级到配置目录下的文件存储；设置了 `GITLINK_CONFIG_DIR` 时路径为 `$GITLINK_CONFIG_DIR/credentials`，否则为 `~/.config/gitlink-cli/credentials`。
 
 ### Q: 如何查看完整的 API 参考？
 
diff --git a/cmd/auth/auth_test.go b/cmd/auth/auth_test.go
index 87fc445..d09602b 100644
--- a/cmd/auth/auth_test.go
+++ b/cmd/auth/auth_test.go
@@ -3,6 +3,7 @@ package auth
 import (
 	"errors"
 	"os"
+	"path/filepath"
 	"testing"
 
 	"github.com/spf13/cobra"
@@ -11,6 +12,13 @@ import (
 	internalAuth "github.com/gitlink-org/gitlink-cli/internal/auth"
 )
 
+func tempConfigDir(t *testing.T) string {
+	t.Helper()
+	dir := t.TempDir()
+	t.Setenv("GITLINK_CONFIG_DIR", dir)
+	return dir
+}
+
 func TestEnvTokenVar(t *testing.T) {
 	if envTokenVar != "GITLINK_TOKEN" {
 		t.Fatalf("envTokenVar = %q, want GITLINK_TOKEN", envTokenVar)
@@ -61,7 +69,7 @@ func TestLoginTokenFlag(t *testing.T) {
 
 func TestStatusCmdNotLoggedIn(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	t.Setenv("HOME", t.TempDir())
+	tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
 	_ = internalAuth.DeleteToken()
 
@@ -76,7 +84,7 @@ func TestStatusCmdNotLoggedIn(t *testing.T) {
 
 func TestStatusCmdEnvToken(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	t.Setenv("HOME", t.TempDir())
+	tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "env-token-123")
 	_ = internalAuth.DeleteToken()
 
@@ -86,12 +94,11 @@ func TestStatusCmdEnvToken(t *testing.T) {
 
 func TestStatusCmdStoredToken(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	dir := t.TempDir()
-	t.Setenv("HOME", dir)
+	dir := tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
 
-	os.MkdirAll(dir+"/.config/gitlink-cli", 0700)
-	os.WriteFile(dir+"/.config/gitlink-cli/credentials", []byte("cookie:test=abc"), 0600)
+	os.MkdirAll(dir, 0700)
+	os.WriteFile(filepath.Join(dir, "credentials"), []byte("cookie:test=abc"), 0600)
 
 	cmd := findSub(NewAuthCmd(), "status")
 	cmd.RunE(cmd, nil)
@@ -99,12 +106,11 @@ func TestStatusCmdStoredToken(t *testing.T) {
 
 func TestStatusCmdEnvAndStoredToken(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	dir := t.TempDir()
-	t.Setenv("HOME", dir)
+	dir := tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "env-token")
 
-	os.MkdirAll(dir+"/.config/gitlink-cli", 0700)
-	os.WriteFile(dir+"/.config/gitlink-cli/credentials", []byte("stored-token"), 0600)
+	os.MkdirAll(dir, 0700)
+	os.WriteFile(filepath.Join(dir, "credentials"), []byte("stored-token"), 0600)
 
 	cmd := findSub(NewAuthCmd(), "status")
 	if err := cmd.RunE(cmd, nil); err != nil {
@@ -114,9 +120,9 @@ func TestStatusCmdEnvAndStoredToken(t *testing.T) {
 
 func TestStatusCmdStoredTokenButLoadFails(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	t.Setenv("HOME", t.TempDir())
+	tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
-	// Don't create credentials file — LoadToken returns empty
+	// Do not create credentials; LoadToken should return empty.
 
 	cmd := findSub(NewAuthCmd(), "status")
 	if err := cmd.RunE(cmd, nil); err != nil {
@@ -124,29 +130,26 @@ func TestStatusCmdStoredTokenButLoadFails(t *testing.T) {
 	}
 }
 
-func TestLogoutCmdError(t *testing.T) {
+func TestLogoutCmdNoStoredToken(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	t.Setenv("HOME", t.TempDir())
+	tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
-	// Don't create credentials dir — DeleteToken will fail
+	// Do not create credentials; logout should be idempotent.
 
 	cmd := findSub(NewAuthCmd(), "logout")
-	err := cmd.RunE(cmd, nil)
-	if err == nil {
-		t.Fatal("expected error when DeleteToken fails")
+	if err := cmd.RunE(cmd, nil); err != nil {
+		t.Fatalf("logout should succeed without stored token: %v", err)
 	}
 }
 
 func TestLogoutCmd(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	home := t.TempDir()
-	t.Setenv("HOME", home)
+	dir := tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
 
 	// Store a token first so DeleteToken has something to delete
-	credDir := home + "/.config/gitlink-cli"
-	os.MkdirAll(credDir, 0700)
-	os.WriteFile(credDir+"/credentials", []byte("some-token"), 0600)
+	os.MkdirAll(dir, 0700)
+	os.WriteFile(filepath.Join(dir, "credentials"), []byte("some-token"), 0600)
 
 	cmd := findSub(NewAuthCmd(), "logout")
 	if cmd == nil {
@@ -159,8 +162,7 @@ func TestLogoutCmd(t *testing.T) {
 
 func TestLoginWithToken(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	home := t.TempDir()
-	t.Setenv("HOME", home)
+	dir := tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
 
 	// Mock stdin
@@ -185,7 +187,7 @@ func TestLoginWithToken(t *testing.T) {
 	}
 
 	// Verify token was saved to file
-	data, err := os.ReadFile(home + "/.config/gitlink-cli/credentials")
+	data, err := os.ReadFile(filepath.Join(dir, "credentials"))
 	if err != nil {
 		t.Fatalf("read credentials: %v", err)
 	}
@@ -196,7 +198,7 @@ func TestLoginWithToken(t *testing.T) {
 
 func TestLoginWithTokenEmpty(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	t.Setenv("HOME", t.TempDir())
+	tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
 
 	oldStdin := os.Stdin
@@ -219,7 +221,7 @@ func TestLoginWithTokenEmpty(t *testing.T) {
 
 func TestLoginWithPasswordNoTerminal(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	t.Setenv("HOME", t.TempDir())
+	tempConfigDir(t)
 	t.Setenv("GITLINK_TOKEN", "")
 
 	// term.ReadPassword will fail because test has no terminal
diff --git a/doc/changes/auth-config-dir-fallback.md b/doc/changes/auth-config-dir-fallback.md
new file mode 100644
index 0000000..57d49dd
--- /dev/null
+++ b/doc/changes/auth-config-dir-fallback.md
@@ -0,0 +1,7 @@
+# 认证凭据 fallback 配置目录一致性修复
+
+`gitlink-cli` 的主配置文件已经支持通过 `GITLINK_CONFIG_DIR` 指定配置目录，但认证模块在系统 Keychain 不可用时仍然把 fallback 凭据写到用户 home 下的 `~/.config/gitlink-cli/credentials`。这会让 CI、Windows 测试、Agent 沙箱和多账号隔离场景出现配置目录与凭据目录不一致的问题，也会导致测试中设置临时 HOME 后仍读写真实用户目录。
+
+本次修复让文件凭据路径统一复用 `internal/config.ConfigDir()`：设置 `GITLINK_CONFIG_DIR` 时，fallback 凭据保存到 `$GITLINK_CONFIG_DIR/credentials`；未设置时仍保持原有默认路径。`auth logout` 在 fallback 文件不存在时也改为幂等成功，避免用户已经没有本地凭据时退出登录反而报错。
+
+测试同步改为使用 `GITLINK_CONFIG_DIR` 隔离凭据目录，覆盖默认配置目录、文件创建、保存/读取/删除、Keychain 不可用 fallback、无凭据登出等场景。该修复提升了跨平台稳定性，也让本地全量测试不再因为 Windows `HOME`/`USERPROFILE` 解析差异污染真实用户凭据目录。
diff --git a/internal/auth/token_store.go b/internal/auth/token_store.go
index 35b260c..467e346 100644
--- a/internal/auth/token_store.go
+++ b/internal/auth/token_store.go
@@ -4,6 +4,7 @@ import (
 	"os"
 	"path/filepath"
 
+	"github.com/gitlink-org/gitlink-cli/internal/config"
 	"github.com/zalando/go-keyring"
 )
 
@@ -41,8 +42,7 @@ func DeleteToken() error {
 // File-based fallback
 
 func credentialPath() string {
-	home, _ := os.UserHomeDir()
-	return filepath.Join(home, ".config", "gitlink-cli", "credentials")
+	return filepath.Join(config.ConfigDir(), "credentials")
 }
 
 func storeTokenFile(token string) error {
@@ -62,5 +62,9 @@ func loadTokenFile() (string, error) {
 }
 
 func deleteTokenFile() error {
-	return os.Remove(credentialPath())
+	err := os.Remove(credentialPath())
+	if os.IsNotExist(err) {
+		return nil
+	}
+	return err
 }
diff --git a/internal/auth/token_store_test.go b/internal/auth/token_store_test.go
index 49bcc5c..af57b11 100644
--- a/internal/auth/token_store_test.go
+++ b/internal/auth/token_store_test.go
@@ -13,11 +13,19 @@ func tempHome(t *testing.T) string {
 	t.Helper()
 	dir := t.TempDir()
 	t.Setenv("HOME", dir)
+	t.Setenv("USERPROFILE", dir)
+	return dir
+}
+
+func tempConfigDir(t *testing.T) string {
+	t.Helper()
+	dir := t.TempDir()
+	t.Setenv("GITLINK_CONFIG_DIR", dir)
 	return dir
 }
 
 func TestStoreLoadDeleteTokenFile(t *testing.T) {
-	tempHome(t)
+	tempConfigDir(t)
 
 	// First, delete any existing token
 	_ = deleteTokenFile()
@@ -55,20 +63,31 @@ func TestStoreLoadDeleteTokenFile(t *testing.T) {
 }
 
 func TestCredentialPath(t *testing.T) {
-	tempHome(t)
+	dir := tempConfigDir(t)
 	got := credentialPath()
-	expected := filepath.Join(os.Getenv("HOME"), ".config", "gitlink-cli", "credentials")
+	expected := filepath.Join(dir, "credentials")
+	if got != expected {
+		t.Fatalf("credentialPath = %q, want %q", got, expected)
+	}
+}
+
+func TestCredentialPathDefaultsToConfigDir(t *testing.T) {
+	home := tempHome(t)
+	t.Setenv("GITLINK_CONFIG_DIR", "")
+
+	got := credentialPath()
+	expected := filepath.Join(home, ".config", "gitlink-cli", "credentials")
 	if got != expected {
 		t.Fatalf("credentialPath = %q, want %q", got, expected)
 	}
 }
 
 func TestStoreTokenFileCreatesDir(t *testing.T) {
-	home := tempHome(t)
+	dir := tempConfigDir(t)
 	_ = deleteTokenFile()
 
 	// Config dir shouldn't exist yet
-	credDir := filepath.Join(home, ".config", "gitlink-cli")
+	credDir := dir
 	os.RemoveAll(credDir)
 
 	if err := storeTokenFile("new-token"); err != nil {
@@ -86,17 +105,16 @@ func TestStoreTokenFileCreatesDir(t *testing.T) {
 }
 
 func TestDeleteTokenFileNonExistent(t *testing.T) {
-	tempHome(t)
+	tempConfigDir(t)
 	_ = deleteTokenFile()
-	// Deleting non-existent file should return an error from os.Remove
-	err := deleteTokenFile()
-	if err == nil {
-		t.Fatal("expected error deleting non-existent file")
+	// Logout-style cleanup should be idempotent when fallback credentials do not exist.
+	if err := deleteTokenFile(); err != nil {
+		t.Fatalf("deleteTokenFile error: %v", err)
 	}
 }
 
 func TestStoreLoadTokenFileEmpty(t *testing.T) {
-	tempHome(t)
+	tempConfigDir(t)
 	_ = deleteTokenFile()
 
 	if err := storeTokenFile(""); err != nil {
@@ -114,14 +132,14 @@ func TestStoreLoadTokenFileEmpty(t *testing.T) {
 
 func TestStoreTokenFallback(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	home := tempHome(t)
+	dir := tempConfigDir(t)
 	_ = deleteTokenFile()
 
 	if err := StoreToken("keychain-fallback-token"); err != nil {
 		t.Fatalf("StoreToken error: %v", err)
 	}
 
-	data, err := os.ReadFile(filepath.Join(home, ".config", "gitlink-cli", "credentials"))
+	data, err := os.ReadFile(filepath.Join(dir, "credentials"))
 	if err != nil {
 		t.Fatalf("read error: %v", err)
 	}
@@ -132,10 +150,10 @@ func TestStoreTokenFallback(t *testing.T) {
 
 func TestDeleteTokenFallback(t *testing.T) {
 	keyring.MockInitWithError(errors.New("keychain unavailable"))
-	home := tempHome(t)
+	dir := tempConfigDir(t)
 	_ = deleteTokenFile()
 
-	p := filepath.Join(home, ".config", "gitlink-cli", "credentials")
+	p := filepath.Join(dir, "credentials")
 	os.MkdirAll(filepath.Dir(p), 0700)
 	os.WriteFile(p, []byte("delete-me"), 0600)
 
diff --git a/skills/gitlink-shared/SKILL.md b/skills/gitlink-shared/SKILL.md
index d1f9d33..8312933 100644
--- a/skills/gitlink-shared/SKILL.md
+++ b/skills/gitlink-shared/SKILL.md
@@ -34,7 +34,7 @@ gitlink-cli auth logout
 
 - GitLink Token 有效期 **7 天**，过期需重新登录
 - Token 存储在 OS Keychain（macOS Keychain / Linux Secret Service / Windows Credential Manager）
-- Fallback 存储：`~/.config/gitlink-cli/credentials`
+- Fallback 存储：`$GITLINK_CONFIG_DIR/credentials`（未设置时为 `~/.config/gitlink-cli/credentials`）
 
 ### 认证错误处理