diff --git a/mcp_server.py b/mcp_server.py
index 8f33c43..ae7e711 100644
--- a/mcp_server.py
+++ b/mcp_server.py
@@ -720,9 +720,9 @@ def gitea_edit_pr(
     Returns:
         dict with success status and details of the edited PR.
     """
-    h, o, r = _resolve(remote, host, org, repo)
-    auth = _auth(h)
-    url = f"{repo_api_url(h, o, r)}/pulls/{pr_number}"
+    # Validate inputs BEFORE any auth/profile resolution or API setup: a
+    # no-fields call is a pure validation error and must not depend on
+    # credentials, network, or environment configuration.
     payload = {}
     if title is not None:
         payload["title"] = title
@@ -736,6 +736,10 @@ def gitea_edit_pr(
     if not payload:
         raise ValueError("At least one field to edit (title, body, state, base) must be provided.")
 
+    h, o, r = _resolve(remote, host, org, repo)
+    auth = _auth(h)
+    url = f"{repo_api_url(h, o, r)}/pulls/{pr_number}"
+
     with _audited("edit_pr", host=h, remote=remote, org=o, repo=r,
                   pr_number=pr_number, request_metadata={"fields": sorted(payload)}):
         data = api_request("PATCH", url, auth, payload)
diff --git a/tests/test_mcp_server.py b/tests/test_mcp_server.py
index b62c2d3..85a47d9 100644
--- a/tests/test_mcp_server.py
+++ b/tests/test_mcp_server.py
@@ -737,6 +737,17 @@ class TestEditPR(unittest.TestCase):
         with self.assertRaises(ValueError):
             gitea_edit_pr(pr_number=1)
 
+    @patch("mcp_server.api_request")
+    @patch("mcp_server.get_auth_header")
+    def test_edit_pr_no_fields_validates_before_auth(self, mock_auth, mock_api):
+        # No-fields validation must not depend on credentials/network: it raises
+        # ValueError before touching auth or the API, even with no creds.
+        mock_auth.return_value = None  # simulate an unauthenticated environment
+        with self.assertRaises(ValueError):
+            gitea_edit_pr(pr_number=1)
+        mock_auth.assert_not_called()
+        mock_api.assert_not_called()
+
 
 # ---------------------------------------------------------------------------
 # Get File