diff --git a/NAMESPACE b/NAMESPACE
index 61c30e0..dc8099e 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -41,6 +41,9 @@ S3method(rm_data,character)
 S3method(rm_data,default)
 S3method(rm_data,git_repository)
 S3method(summary,git2rdata)
+S3method(update_description,character)
+S3method(update_description,default)
+S3method(update_description,git_repository)
 S3method(upgrade_data,character)
 S3method(upgrade_data,default)
 S3method(upgrade_data,git_repository)
diff --git a/R/update_description.R b/R/update_description.R
index 3a5830b..ac65ca5 100644
--- a/R/update_description.R
+++ b/R/update_description.R
@@ -18,6 +18,30 @@
 #' @importFrom assertthat assert_that has_name
 update_description <- function(
   file, root = ".", field_description, name, title, description
+) {
+  UseMethod("update_description", root)
+}
+
+#' @export
+update_description.default <- function(
+  file, root = ".", field_description, name, title, description
+) {
+  stop("a 'root' of class ", class(root), " is not supported", call. = FALSE)
+}
+
+#' @export
+update_description.git_repository <- function(
+    file, root = ".", field_description, name, title, description
+) {
+  update_description(
+    file = file, root = workdir(root), name = name, title = title,
+    description = description, field_description = field_description
+  )
+}
+
+#' @export
+update_description.character <- function(
+  file, root = ".", field_description, name, title, description
 ) {
   root <- normalizePath(root, winslash = "/", mustWork = TRUE)
   file <- clean_data_path(root = root, file = file)
diff --git a/tests/testthat/test_c_description.R b/tests/testthat/test_d_description.R
similarity index 84%
rename from tests/testthat/test_c_description.R
rename to tests/testthat/test_d_description.R
index df58d68..360440f 100644
--- a/tests/testthat/test_c_description.R
+++ b/tests/testthat/test_d_description.R
@@ -1,4 +1,11 @@
 test_that("description", {
+  expect_error(
+    update_description(
+      file = "test", root = data.frame()
+    ),
+    "a 'root' of class data.frame is not supported"
+  )
+
   root <- tempfile(pattern = "git2rdata-description")
   dir.create(root)
 
@@ -35,6 +42,12 @@ test_that("description", {
   expect_output(display_metadata(output, minimal = FALSE), "Table name: NA")
   expect_output(display_metadata(output), "Table name: NA")
 
+  root <- git2r::init(root)
+  git2r::config(root, user.name = "Alice", user.email = "alice@example.org")
+  writeLines("ignore.*\nforce.*", file.path(git2r::workdir(root), ".gitignore"))
+  git2r::add(root, ".gitignore")
+  commit(root, "initial commit")
+
   expect_null(
     update_description(
       file = "test", root = root, name = "my_table", title = "My Table",