diff --git a/docs/CHANGELOG.md b/docs/CHANGELOG.md
index eceb3fced..a82b7a443 100644
--- a/docs/CHANGELOG.md
+++ b/docs/CHANGELOG.md
@@ -7,6 +7,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+- Fixed a bug where `rsconnect deploy manifest manifest.json` (and other deploy
+  commands given a bare filename) failed to detect git metadata. The directory
+  passed to git detection was empty in that case, which caused detection to be
+  silently skipped; it now falls back to the current directory.
 - The `CONNECT_SERVER_VERSION` environment variable can now be set to tell
   rsconnect-python which Connect version to assume for feature-availability
   checks. Some servers can be configured to suppress their version, which makes
diff --git a/rsconnect/git_metadata.py b/rsconnect/git_metadata.py
index a5480e194..a0c315724 100644
--- a/rsconnect/git_metadata.py
+++ b/rsconnect/git_metadata.py
@@ -22,7 +22,9 @@ def _run_git_command(args: list[str], cwd: str) -> Optional[str]:
     try:
         result = subprocess.run(
             ["git"] + args,
-            cwd=cwd,
+            # dirname() of a bare filename (e.g. "manifest.json") yields "",
+            # which subprocess rejects; treat it as the current directory.
+            cwd=cwd or ".",
             capture_output=True,
             text=True,
             timeout=5,
diff --git a/tests/test_git_metadata.py b/tests/test_git_metadata.py
index 0faf21b76..a4722a1e3 100644
--- a/tests/test_git_metadata.py
+++ b/tests/test_git_metadata.py
@@ -123,6 +123,19 @@ def test_detect_git_metadata_non_git_dir(self):
             metadata = detect_git_metadata(tmpdir)
             assert metadata == {}
 
+    def test_is_git_repo_empty_dir_uses_cwd(self, git_repo, monkeypatch):
+        # dirname("manifest.json") yields "", which subprocess rejects as cwd.
+        # An empty directory should be treated as the current directory so that
+        # `rsconnect deploy manifest manifest.json` still detects git metadata.
+        monkeypatch.chdir(git_repo)
+        assert is_git_repo("") is True
+
+    def test_detect_git_metadata_empty_dir_uses_cwd(self, git_repo, monkeypatch):
+        monkeypatch.chdir(git_repo)
+        metadata = detect_git_metadata("")
+        assert metadata["source"] == "git"
+        assert metadata["source_repo"] == "https://github.com/user/repo.git"
+
 
 class TestServerVersionSupport:
     def test_server_supports_git_metadata(self):