diff --git a/internal/auth/claude/token.go b/internal/auth/claude/token.go
index cda10d58..c36f8e76 100644
--- a/internal/auth/claude/token.go
+++ b/internal/auth/claude/token.go
@@ -36,11 +36,21 @@ type ClaudeTokenStorage struct {
 
 	// Expire is the timestamp when the current access token expires.
 	Expire string `json:"expired"`
+
+	// Metadata holds arbitrary key-value pairs injected via hooks.
+	// It is not exported to JSON directly to allow flattening during serialization.
+	Metadata map[string]any `json:"-"`
+}
+
+// SetMetadata allows external callers to inject metadata into the storage before saving.
+func (ts *ClaudeTokenStorage) SetMetadata(meta map[string]any) {
+	ts.Metadata = meta
 }
 
 // SaveTokenToFile serializes the Claude token storage to a JSON file.
 // This method creates the necessary directory structure and writes the token
 // data in JSON format to the specified file path for persistent storage.
+// It merges any injected metadata into the top-level JSON object.
 //
 // Parameters:
 //   - authFilePath: The full path where the token file should be saved
@@ -65,8 +75,25 @@ func (ts *ClaudeTokenStorage) SaveTokenToFile(authFilePath string) error {
 		_ = f.Close()
 	}()
 
+	// Convert struct to map for merging
+	data := make(map[string]any)
+	temp, errJson := json.Marshal(ts)
+	if errJson != nil {
+		return fmt.Errorf("failed to marshal struct: %w", errJson)
+	}
+	if errUnmarshal := json.Unmarshal(temp, &data); errUnmarshal != nil {
+		return fmt.Errorf("failed to unmarshal struct map: %w", errUnmarshal)
+	}
+
+	// Merge extra metadata
+	if ts.Metadata != nil {
+		for k, v := range ts.Metadata {
+			data[k] = v
+		}
+	}
+
 	// Encode and write the token data as JSON
-	if err = json.NewEncoder(f).Encode(ts); err != nil {
+	if err = json.NewEncoder(f).Encode(data); err != nil {
 		return fmt.Errorf("failed to write token to file: %w", err)
 	}
 	return nil
diff --git a/internal/auth/codex/token.go b/internal/auth/codex/token.go
index e93fc417..1ea84f3a 100644
--- a/internal/auth/codex/token.go
+++ b/internal/auth/codex/token.go
@@ -32,11 +32,21 @@ type CodexTokenStorage struct {
 	Type string `json:"type"`
 	// Expire is the timestamp when the current access token expires.
 	Expire string `json:"expired"`
+
+	// Metadata holds arbitrary key-value pairs injected via hooks.
+	// It is not exported to JSON directly to allow flattening during serialization.
+	Metadata map[string]any `json:"-"`
+}
+
+// SetMetadata allows external callers to inject metadata into the storage before saving.
+func (ts *CodexTokenStorage) SetMetadata(meta map[string]any) {
+	ts.Metadata = meta
 }
 
 // SaveTokenToFile serializes the Codex token storage to a JSON file.
 // This method creates the necessary directory structure and writes the token
 // data in JSON format to the specified file path for persistent storage.
+// It merges any injected metadata into the top-level JSON object.
 //
 // Parameters:
 //   - authFilePath: The full path where the token file should be saved
@@ -58,9 +68,25 @@ func (ts *CodexTokenStorage) SaveTokenToFile(authFilePath string) error {
 		_ = f.Close()
 	}()
 
-	if err = json.NewEncoder(f).Encode(ts); err != nil {
+	// Convert struct to map for merging
+	data := make(map[string]any)
+	temp, errJson := json.Marshal(ts)
+	if errJson != nil {
+		return fmt.Errorf("failed to marshal struct: %w", errJson)
+	}
+	if errUnmarshal := json.Unmarshal(temp, &data); errUnmarshal != nil {
+		return fmt.Errorf("failed to unmarshal struct map: %w", errUnmarshal)
+	}
+
+	// Merge extra metadata
+	if ts.Metadata != nil {
+		for k, v := range ts.Metadata {
+			data[k] = v
+		}
+	}
+
+	if err = json.NewEncoder(f).Encode(data); err != nil {
 		return fmt.Errorf("failed to write token to file: %w", err)
 	}
 	return nil
-
 }
diff --git a/internal/auth/iflow/iflow_token.go b/internal/auth/iflow/iflow_token.go
index 6d2beb39..13eb7de1 100644
--- a/internal/auth/iflow/iflow_token.go
+++ b/internal/auth/iflow/iflow_token.go
@@ -21,6 +21,15 @@ type IFlowTokenStorage struct {
 	Scope        string `json:"scope"`
 	Cookie       string `json:"cookie"`
 	Type         string `json:"type"`
+
+	// Metadata holds arbitrary key-value pairs injected via hooks.
+	// It is not exported to JSON directly to allow flattening during serialization.
+	Metadata map[string]any `json:"-"`
+}
+
+// SetMetadata allows external callers to inject metadata into the storage before saving.
+func (ts *IFlowTokenStorage) SetMetadata(meta map[string]any) {
+	ts.Metadata = meta
 }
 
 // SaveTokenToFile serialises the token storage to disk.
@@ -37,7 +46,24 @@ func (ts *IFlowTokenStorage) SaveTokenToFile(authFilePath string) error {
 	}
 	defer func() { _ = f.Close() }()
 
-	if err = json.NewEncoder(f).Encode(ts); err != nil {
+	// Convert struct to map for merging
+	data := make(map[string]any)
+	temp, errJson := json.Marshal(ts)
+	if errJson != nil {
+		return fmt.Errorf("failed to marshal struct: %w", errJson)
+	}
+	if errUnmarshal := json.Unmarshal(temp, &data); errUnmarshal != nil {
+		return fmt.Errorf("failed to unmarshal struct map: %w", errUnmarshal)
+	}
+
+	// Merge extra metadata
+	if ts.Metadata != nil {
+		for k, v := range ts.Metadata {
+			data[k] = v
+		}
+	}
+
+	if err = json.NewEncoder(f).Encode(data); err != nil {
 		return fmt.Errorf("iflow token: encode token failed: %w", err)
 	}
 	return nil
diff --git a/internal/auth/kimi/token.go b/internal/auth/kimi/token.go
index d4d06b64..15171d93 100644
--- a/internal/auth/kimi/token.go
+++ b/internal/auth/kimi/token.go
@@ -29,6 +29,15 @@ type KimiTokenStorage struct {
 	Expired string `json:"expired,omitempty"`
 	// Type indicates the authentication provider type, always "kimi" for this storage.
 	Type string `json:"type"`
+
+	// Metadata holds arbitrary key-value pairs injected via hooks.
+	// It is not exported to JSON directly to allow flattening during serialization.
+	Metadata map[string]any `json:"-"`
+}
+
+// SetMetadata allows external callers to inject metadata into the storage before saving.
+func (ts *KimiTokenStorage) SetMetadata(meta map[string]any) {
+	ts.Metadata = meta
 }
 
 // KimiTokenData holds the raw OAuth token response from Kimi.
@@ -86,9 +95,26 @@ func (ts *KimiTokenStorage) SaveTokenToFile(authFilePath string) error {
 		_ = f.Close()
 	}()
 
+	// Convert struct to map for merging
+	data := make(map[string]any)
+	temp, errJson := json.Marshal(ts)
+	if errJson != nil {
+		return fmt.Errorf("failed to marshal struct: %w", errJson)
+	}
+	if errUnmarshal := json.Unmarshal(temp, &data); errUnmarshal != nil {
+		return fmt.Errorf("failed to unmarshal struct map: %w", errUnmarshal)
+	}
+
+	// Merge extra metadata
+	if ts.Metadata != nil {
+		for k, v := range ts.Metadata {
+			data[k] = v
+		}
+	}
+
 	encoder := json.NewEncoder(f)
 	encoder.SetIndent("", "  ")
-	if err = encoder.Encode(ts); err != nil {
+	if err = encoder.Encode(data); err != nil {
 		return fmt.Errorf("failed to write token to file: %w", err)
 	}
 	return nil
diff --git a/internal/auth/qwen/qwen_token.go b/internal/auth/qwen/qwen_token.go
index 4a2b3a2d..8037bdb7 100644
--- a/internal/auth/qwen/qwen_token.go
+++ b/internal/auth/qwen/qwen_token.go
@@ -30,11 +30,21 @@ type QwenTokenStorage struct {
 	Type string `json:"type"`
 	// Expire is the timestamp when the current access token expires.
 	Expire string `json:"expired"`
+
+	// Metadata holds arbitrary key-value pairs injected via hooks.
+	// It is not exported to JSON directly to allow flattening during serialization.
+	Metadata map[string]any `json:"-"`
+}
+
+// SetMetadata allows external callers to inject metadata into the storage before saving.
+func (ts *QwenTokenStorage) SetMetadata(meta map[string]any) {
+	ts.Metadata = meta
 }
 
 // SaveTokenToFile serializes the Qwen token storage to a JSON file.
 // This method creates the necessary directory structure and writes the token
 // data in JSON format to the specified file path for persistent storage.
+// It merges any injected metadata into the top-level JSON object.
 //
 // Parameters:
 //   - authFilePath: The full path where the token file should be saved
@@ -56,7 +66,24 @@ func (ts *QwenTokenStorage) SaveTokenToFile(authFilePath string) error {
 		_ = f.Close()
 	}()
 
-	if err = json.NewEncoder(f).Encode(ts); err != nil {
+	// Convert struct to map for merging
+	data := make(map[string]any)
+	temp, errJson := json.Marshal(ts)
+	if errJson != nil {
+		return fmt.Errorf("failed to marshal struct: %w", errJson)
+	}
+	if errUnmarshal := json.Unmarshal(temp, &data); errUnmarshal != nil {
+		return fmt.Errorf("failed to unmarshal struct map: %w", errUnmarshal)
+	}
+
+	// Merge extra metadata
+	if ts.Metadata != nil {
+		for k, v := range ts.Metadata {
+			data[k] = v
+		}
+	}
+
+	if err = json.NewEncoder(f).Encode(data); err != nil {
 		return fmt.Errorf("failed to write token to file: %w", err)
 	}
 	return nil