feat(captain): validate custom tools

internal/handler/api/v1/captain_custom_tool_handler.go

@@ -47,6 +47,9 @@ func (h *CaptainCustomToolHandler) Create(c *gin.Context) {
 			c.JSON(http.StatusUnprocessableEntity, gin.H{"error": service.ErrCaptainCustomToolLimitExceeded.Error()})
 			return
 		}
+		if renderCaptainCustomToolValidationError(c, err) {
+			return
+		}
 		response.AbortWithStatusError(c, http.StatusInternalServerError, response.ErrInternal, "failed to create custom tool")
 		return
 	}
@@ -107,6 +110,9 @@ func (h *CaptainCustomToolHandler) Update(c *gin.Context) {
 	tool, err := h.svc.UpdateByAccount(c.Request.Context(), accountID, id, &req)
 	if err != nil {
 		applogger.L().Errorf("Update captain custom tool: %v", err)
+		if renderCaptainCustomToolValidationError(c, err) {
+			return
+		}
 		handleServiceError(c, err)
 		return
 	}
@@ -227,6 +233,18 @@ func (h *CaptainCustomToolHandler) ensureCustomToolsEnabled(c *gin.Context, acco
 	return false
 }
 
+func renderCaptainCustomToolValidationError(c *gin.Context, err error) bool {
+	var validationErr *service.CaptainCustomToolValidationError
+	if !errors.As(err, &validationErr) {
+		return false
+	}
+	c.JSON(http.StatusUnprocessableEntity, gin.H{
+		"message":    validationErr.Message,
+		"attributes": validationErr.Attributes,
+	})
+	return true
+}
+
 func captainCustomToolPayload(tool *model.CaptainCustomTool) gin.H {
 	return gin.H{
 		"id":                tool.ID,