fix: specify sha is required (github#320)

Author: crondinini

pkg/github/repositories.go

@@ -228,7 +228,7 @@ func ListBranches(getClient GetClientFn, t translations.TranslationHelperFunc) (
 // CreateOrUpdateFile creates a tool to create or update a file in a GitHub repository.
 func CreateOrUpdateFile(getClient GetClientFn, t translations.TranslationHelperFunc) (tool mcp.Tool, handler server.ToolHandlerFunc) {
 	return mcp.NewTool("create_or_update_file",
-			mcp.WithDescription(t("TOOL_CREATE_OR_UPDATE_FILE_DESCRIPTION", "Create or update a single file in a GitHub repository")),
+			mcp.WithDescription(t("TOOL_CREATE_OR_UPDATE_FILE_DESCRIPTION", "Create or update a single file in a GitHub repository. If updating, you must provide the SHA of the file you want to update.")),
 			mcp.WithToolAnnotation(mcp.ToolAnnotation{
 				Title:        t("TOOL_CREATE_OR_UPDATE_FILE_USER_TITLE", "Create or update file"),
 				ReadOnlyHint: false,