diff --git a/pyproject.toml b/pyproject.toml
index d92c64de1..243e2838e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -95,7 +95,7 @@ dev = [
     "Flake8-pyproject>=1.2.3",
     "isort>=5.10.1",
     "libsass>=0.23.0",
-    "pyright==1.1.369",
+    "pyright>=1.1.383",
     "pre-commit>=2.15.0",
     "wheel",
     "matplotlib",
diff --git a/shiny/_utils.py b/shiny/_utils.py
index aff24044b..a52997d72 100644
--- a/shiny/_utils.py
+++ b/shiny/_utils.py
@@ -85,7 +85,7 @@ def guess_mime_type(
     if url:
         # Work around issue #1601, some installations of Windows 10 return text/plain
         # as the mime type for .js files
-        _, ext = os.path.splitext(os.fspath(url))
+        _, ext = os.path.splitext(os.fspath(str(url)))
         if ext.lower() in [".js", ".mjs", ".cjs"]:
             return "text/javascript"
     return mimetypes.guess_type(url, strict)[0] or default
diff --git a/tests/playwright/shiny/components/data_frame/edit/app.py b/tests/playwright/shiny/components/data_frame/edit/app.py
index c759bf9d7..2f8707e39 100644
--- a/tests/playwright/shiny/components/data_frame/edit/app.py
+++ b/tests/playwright/shiny/components/data_frame/edit/app.py
@@ -89,7 +89,11 @@ def gt_styles(df_gt: gt.GT) -> list[StyleInfo]:
     ret: list[StyleInfo] = []
     for style in styles:
         location = style.locname
-        location = "body" if location == "data" else location
+        location = (
+            "body"
+            if location == "data"  # pyright: ignore[reportUnnecessaryComparison]
+            else location
+        )
         assert location == "body", f"`style.locname` is {location}, expected 'body'"
         rows = style.rownum
         assert rows is not None
diff --git a/tests/playwright/shiny/components/data_frame/styles/great_tables_test_utils.py b/tests/playwright/shiny/components/data_frame/styles/great_tables_test_utils.py
index eb0213417..3ec41f236 100644
--- a/tests/playwright/shiny/components/data_frame/styles/great_tables_test_utils.py
+++ b/tests/playwright/shiny/components/data_frame/styles/great_tables_test_utils.py
@@ -23,7 +23,11 @@ def gt_styles(df_gt: gt.GT) -> list[StyleInfo]:
     ret: list[StyleInfo] = []
     for style in styles:
         location = style.locname
-        location = "body" if location == "data" else location
+        location = (
+            "body"
+            if location == "data"  # pyright: ignore[reportUnnecessaryComparison]
+            else location
+        )
         assert location == "body", f"`style.locname` is {location}, expected 'body'"
         rows = style.rownum
         assert rows is not None
@@ -39,7 +43,7 @@ def gt_styles(df_gt: gt.GT) -> list[StyleInfo]:
             )
         ret.append(
             {
-                "location": location,
+                "location": location,  # pyright: ignore[reportArgumentType]
                 "rows": rows,
                 "cols": cols,
                 "style": style_obj,
diff --git a/tests/playwright/shiny/deprecated/output_transformer/app.py b/tests/playwright/shiny/deprecated/output_transformer/app.py
index 725d9f6f1..3ec9dfe38 100644
--- a/tests/playwright/shiny/deprecated/output_transformer/app.py
+++ b/tests/playwright/shiny/deprecated/output_transformer/app.py
@@ -1,3 +1,9 @@
+# pyright: reportUntypedFunctionDecorator=false
+# pyright: reportUnknownParameterType=false
+# pyright: reportUnknownMemberType=false
+# pyright: reportInvalidTypeForm=false
+# pyright: reportUnknownArgumentType=false
+# pyright: reportArgumentType=false
 from __future__ import annotations
 
 import warnings
diff --git a/tests/playwright/shiny/server/output_transformer/app.py b/tests/playwright/shiny/server/output_transformer/app.py
index 8c988cc62..37d1063dc 100644
--- a/tests/playwright/shiny/server/output_transformer/app.py
+++ b/tests/playwright/shiny/server/output_transformer/app.py
@@ -1,3 +1,8 @@
+# pyright: reportUntypedFunctionDecorator=false
+# pyright: reportUnknownMemberType=false
+# pyright: reportInvalidTypeForm=false
+# pyright: reportUnknownParameterType=false
+# pyright: reportUnknownArgumentType=false
 from __future__ import annotations
 
 from typing import Optional, overload
diff --git a/tests/pytest/test_output_transformer.py b/tests/pytest/test_output_transformer.py
index 0ae494b0c..afd69811a 100644
--- a/tests/pytest/test_output_transformer.py
+++ b/tests/pytest/test_output_transformer.py
@@ -1,3 +1,9 @@
+# pyright: reportUnknownParameterType=false
+# pyright: reportUnknownMemberType=false
+# pyright: reportInvalidTypeForm=false
+# pyright: reportUntypedFunctionDecorator=false
+# pyright: reportUnknownArgumentType=false
+# pyright: reportFunctionMemberAccess=false
 from __future__ import annotations
 
 import asyncio