diff --git a/flake8_trio.py b/flake8_trio.py
index 4b94b70..d51655a 100644
--- a/flake8_trio.py
+++ b/flake8_trio.py
@@ -11,12 +11,11 @@
 
 from __future__ import annotations
 
-import argparse
 import ast
 import keyword
 import tokenize
-from argparse import Namespace
-from collections.abc import Iterable, Sequence
+from argparse import ArgumentTypeError, Namespace
+from collections.abc import Iterable
 from fnmatch import fnmatch
 from typing import Any, NamedTuple, Union, cast
 
@@ -1427,46 +1426,33 @@ def visit_Call(self, node: ast.Call):
                 self.error(node, key, blocking_calls[key])
 
 
-class ListOfIdentifiers(argparse.Action):
-    def __call__(
-        self,
-        parser: argparse.ArgumentParser,
-        namespace: argparse.Namespace,
-        values: Sequence[str] | None,
-        option_string: str | None = None,
-    ):
-        assert values is not None
-        assert option_string is not None
-        for value in values:
-            if keyword.iskeyword(value) or not value.isidentifier():
-                raise argparse.ArgumentError(
-                    self, f"{value!r} is not a valid method identifier"
-                )
-        setattr(namespace, self.dest, values)
-
-
-class ParseDict(argparse.Action):
-    def __call__(
-        self,
-        parser: argparse.ArgumentParser,
-        namespace: argparse.Namespace,
-        values: Sequence[str] | None,
-        option_string: str | None = None,
-    ):
-        res: dict[str, str] = {}
-        splitter = "->"  # avoid ":" because it's part of .ini file syntax
-        assert values is not None
-        for value in values:
-            split_values = list(map(str.strip, value.split(splitter)))
-            if len(split_values) != 2:
-                raise argparse.ArgumentError(
-                    self,
-                    f"Invalid number ({len(split_values)-1}) of splitter "
-                    f"tokens {splitter!r} in {value!r}",
-                )
-            res[split_values[0]] = split_values[1]
-
-        setattr(namespace, self.dest, res)
+# flake8 ignores type parameters if using comma_separated_list
+# so we need to reimplement that ourselves if we want to use "type"
+# to check values
+def parse_trio114_identifiers(raw_value: str) -> list[str]:
+    values = [s.strip() for s in raw_value.split(",") if s.strip()]
+    for value in values:
+        if keyword.iskeyword(value) or not value.isidentifier():
+            raise ArgumentTypeError(f"{value!r} is not a valid method identifier")
+    return values
+
+
+def parse_trio200_dict(raw_value: str) -> dict[str, str]:
+    res: dict[str, str] = {}
+    splitter = "->"  # avoid ":" because it's part of .ini file syntax
+    values = [s.strip() for s in raw_value.split(",") if s.strip()]
+
+    for value in values:
+        split_values = list(map(str.strip, value.split(splitter)))
+        if len(split_values) != 2:
+            # argparse will eat this error message and spit out it's own
+            # if we raise it as ValueError
+            raise ArgumentTypeError(
+                f"Invalid number ({len(split_values)-1}) of splitter "
+                f"tokens {splitter!r} in {value!r}",
+            )
+        res[split_values[0]] = split_values[1]
+    return res
 
 
 class Plugin:
@@ -1484,15 +1470,6 @@ def from_filename(cls, filename: str) -> Plugin:
         return cls(ast.parse(source))
 
     def run(self) -> Iterable[Error]:
-        # temporary workaround, since the Action does not seem to be called properly
-        # by flake8 when parsing from config
-        if isinstance(self.options.trio200_blocking_calls, list):
-            ParseDict([""], dest="trio200_blocking_calls")(
-                None,  # type: ignore
-                self.options,
-                self.options.trio200_blocking_calls,  # type: ignore
-                None,
-            )
         yield from Flake8TrioRunner.run(self._tree, self.options)
 
     @staticmethod
@@ -1513,11 +1490,10 @@ def add_options(option_manager: OptionManager):
         )
         option_manager.add_option(
             "--startable-in-context-manager",
+            type=parse_trio114_identifiers,
             default="",
             parse_from_config=True,
             required=False,
-            comma_separated_list=True,
-            action=ListOfIdentifiers,
             help=(
                 "Comma-separated list of method calls to additionally enable TRIO113 "
                 "warnings for. Will also check for the pattern inside function calls. "
@@ -1529,11 +1505,10 @@ def add_options(option_manager: OptionManager):
         )
         option_manager.add_option(
             "--trio200-blocking-calls",
+            type=parse_trio200_dict,
             default={},
             parse_from_config=True,
             required=False,
-            comma_separated_list=True,
-            action=ParseDict,
             help=(
                 "Comma-separated list of key:value pairs, where key is a [dotted] "
                 "function that if found inside an async function will raise TRIO200, "
diff --git a/tests/test_flake8_trio.py b/tests/test_flake8_trio.py
index c2c99d7..33cd06b 100644
--- a/tests/test_flake8_trio.py
+++ b/tests/test_flake8_trio.py
@@ -80,6 +80,9 @@ def test_eval(test: str, path: str):
         lines = file.readlines()
 
     for lineno, line in enumerate(lines, start=1):
+        # interpret '\n' in comments as actual newlines
+        line = line.replace("\\n", "\n")
+
         line = line.strip()
 
         # add other error codes to check if #INCLUDE is specified
@@ -90,9 +93,7 @@ def test_eval(test: str, path: str):
 
         # add command-line args if specified with #ARGS
         elif reg_match := re.search(r"(?<=ARGS).*", line):
-            for arg in reg_match.group().split(" "):
-                if arg.strip():
-                    parsed_args.append(arg.strip())
+            parsed_args.append(reg_match.group().strip())
 
         # skip commented out lines
         if not line or line[0] == "#":
@@ -444,16 +445,17 @@ def test_200_options(capsys: pytest.CaptureFixture[str]):
                 om.parse_args(args=[f"--trio200-blocking-calls={arg}"])
             )
         out, err = capsys.readouterr()
-        assert not out
+        assert "" == out
         assert all(word in err for word in (str(i), arg, "->"))
 
 
-def test_from_config_file(tmp_path: Path):
+def _test_trio200_from_config_common(tmp_path: Path) -> str:
     tmp_path.joinpath(".flake8").write_text(
         """
 [flake8]
 trio200-blocking-calls =
-  sync_fns.*->the_async_equivalent,
+  other -> async,
+  sync_fns.* -> the_async_equivalent,
 select = TRIO200
 """
     )
@@ -465,12 +467,42 @@ async def foo():
     sync_fns.takes_a_long_time()
 """
     )
+    return (
+        "./example.py:5:5: TRIO200: User-configured blocking sync call sync_fns.* "
+        "in async function, consider replacing with the_async_equivalent.\n"
+    )
+
+
+def test_200_from_config_flake8_internals(
+    tmp_path: Path, capsys: pytest.CaptureFixture[str]
+):
+    # abuse flake8 internals to avoid having to use subprocess
+    # which breaks breakpoints and hinders debugging
+    # TODO: fixture (?) to change working directory
+
+    err_msg = _test_trio200_from_config_common(tmp_path)
+    # replace ./ with tmp_path/
+    err_msg = str(tmp_path) + err_msg[1:]
+
+    from flake8.main.cli import main
+
+    main(
+        argv=[
+            str(tmp_path / "example.py"),
+            "--append-config",
+            str(tmp_path / ".flake8"),
+        ]
+    )
+    out, err = capsys.readouterr()
+    assert not err
+    assert err_msg == out
+
+
+def test_200_from_config_subprocess(tmp_path: Path):
+    err_msg = _test_trio200_from_config_common(tmp_path)
     res = subprocess.run(["flake8"], cwd=tmp_path, capture_output=True)
     assert not res.stderr
-    assert res.stdout == (
-        b"./example.py:5:5: TRIO200: User-configured blocking sync call sync_fns.* "
-        b"in async function, consider replacing with the_async_equivalent.\n"
-    )
+    assert res.stdout == bytes(err_msg, "ascii")
 
 
 @pytest.mark.fuzz
diff --git a/tests/trio200.py b/tests/trio200.py
index 35cb48b..1462662 100644
--- a/tests/trio200.py
+++ b/tests/trio200.py
@@ -1,5 +1,7 @@
 # specify command-line arguments to be used when testing this file.
-# ARGS --trio200-blocking-calls=bar->BAR,bee->SHOULD_NOT_BE_PRINTED,bonnet->SHOULD_NOT_BE_PRINTED,bee.bonnet->BEEBONNET,*.postwild->POSTWILD,prewild.*->PREWILD,*.*.*->TRIPLEDOT
+# Test spaces in options, and trailing comma
+# Cannot test newlines, since argparse splits on those if passed on the CLI
+# ARGS --trio200-blocking-calls=bar -> BAR, bee-> SHOULD_NOT_BE_PRINTED,bonnet ->SHOULD_NOT_BE_PRINTED,bee.bonnet->BEEBONNET,*.postwild->POSTWILD,prewild.*->PREWILD,*.*.*->TRIPLEDOT,
 
 # don't error in sync function
 def foo():
diff --git a/typings/flake8/main/cli.pyi b/typings/flake8/main/cli.pyi
new file mode 100644
index 0000000..f454868
--- /dev/null
+++ b/typings/flake8/main/cli.pyi
@@ -0,0 +1,18 @@
+"""
+This type stub file was generated by pyright.
+"""
+
+from collections.abc import Sequence
+
+"""Command-line implementation of flake8."""
+
+def main(argv: Sequence[str] | None = ...) -> int:
+    """Execute the main bit of the application.
+
+    This handles the creation of an instance of :class:`Application`, runs it,
+    and then exits the application.
+
+    :param argv:
+        The arguments to be passed to the application for parsing.
+    """
+    ...