diff --git a/test/conftest.py b/test/conftest.py
new file mode 100644
index 0000000..28daf73
--- /dev/null
+++ b/test/conftest.py
@@ -0,0 +1,27 @@
+from pathlib import Path
+
+import pytest
+
+from topen import OPTIONS
+
+
+@pytest.fixture
+def fake_id(monkeypatch):
+    monkeypatch.setattr("sys.argv", ["topen", "0"])
+
+
+@pytest.fixture
+def isolate_env(monkeypatch):
+    # delete all existing env vars that could interfere
+    monkeypatch.delenv("EDITOR", raising=False)
+    monkeypatch.delenv("VISUAL", raising=False)
+    for opt in OPTIONS.values():
+        if opt.env:
+            monkeypatch.delenv(opt.env, raising=False)
+
+
+@pytest.fixture
+def fake_rc(tmp_path: Path, monkeypatch):
+    rc = tmp_path / "test.taskrc"
+    monkeypatch.setattr(OPTIONS["task_rc"], "default", rc)
+    return rc
diff --git a/test/test_configuration.py b/test/test_configuration.py
index 8eb6296..7afe8c8 100644
--- a/test/test_configuration.py
+++ b/test/test_configuration.py
@@ -1,94 +1,11 @@
+# pyright: reportUnusedImport=false, reportUnusedParameter=false
+# ruff: noqa: F401, F811
+# ^ Turn off for implicit pytest fixture import
 from pathlib import Path
 
 import pytest
 
-from topen import OPTIONS, TConf, parse_cli, parse_env, parse_rc
-
-
-class TestCli:
-    def test_cli_minimum_id(self, monkeypatch):
-        monkeypatch.setattr("sys.argv", ["topen", "42"])
-        assert parse_cli() == {"task_id": "42"}
-
-    def test_cli_options(self, monkeypatch):
-        monkeypatch.setattr(
-            "sys.argv",
-            [
-                "topen",
-                "123",
-                "--extension",
-                "txt",
-                "--editor",
-                "vim",
-                "--quiet",
-                "True",
-            ],
-        )
-        assert parse_cli() == {
-            "task_id": "123",
-            "notes_ext": "txt",
-            "notes_editor": "vim",
-            "notes_quiet": True,
-        }
-
-
-@pytest.fixture
-def isolate_env(monkeypatch):
-    # delete all existing env vars that could interfere
-    monkeypatch.delenv("EDITOR", raising=False)
-    monkeypatch.delenv("VISUAL", raising=False)
-    for opt in OPTIONS.values():
-        if opt.env:
-            monkeypatch.delenv(opt.env, raising=False)
-
-
-class TestEnv:
-    def test_env_notes_ext(self, isolate_env, monkeypatch):
-        monkeypatch.setenv("TOPEN_NOTES_DIR", "/blablubb")
-        monkeypatch.setenv("TOPEN_NOTES_EXT", "rst")
-        monkeypatch.setenv("TOPEN_NOTES_ANNOT", "qmd")
-        monkeypatch.setenv("TOPEN_NOTES_EDITOR", "vim")
-        monkeypatch.setenv("TOPEN_NOTES_QUIET", "true")
-        env = parse_env()
-        assert env["notes_dir"] == Path("/blablubb")
-        assert env["notes_ext"] == "rst"
-        assert env["notes_annot"] == "qmd"
-        assert env["notes_editor"] == "vim"
-        assert env["notes_quiet"] is True
-
-    def test_env_task_rc(self, isolate_env, monkeypatch):
-        monkeypatch.setenv("TASKRC", "/a/dir/that/dont/exist/file")
-        monkeypatch.setenv("TASKDATA", "~/somewhere/tasks")
-        env = parse_env()
-        assert env["task_rc"] == Path("/a/dir/that/dont/exist/file")
-        assert env["task_data"] == Path("~/somewhere/tasks")
-
-
-@pytest.fixture
-def fake_rc(tmp_path: Path, monkeypatch):
-    rc = tmp_path / "test.taskrc"
-    monkeypatch.setattr(OPTIONS["task_rc"], "default", rc)
-    return rc
-
-
-class TestRcFile:
-    def test_taskrc_parsing(self, fake_rc):
-        fake_rc.write_text("""
-        data.location=~/.taskies
-        notes.dir=/there
-        notes.ext=yaml
-        notes.annot=Boo!
-        notes.editor=micro
-        notes.quiet=true
-        """)
-        rc_cfg = parse_rc(fake_rc)
-        assert rc_cfg["task_data"] == Path("~/.taskies")
-        assert rc_cfg["notes_dir"] == Path("/there")
-        assert rc_cfg["notes_ext"] == "yaml"
-        assert rc_cfg["notes_annot"] == "Boo!"
-        assert rc_cfg["notes_editor"] == "micro"
-        assert rc_cfg["notes_quiet"] is True
-
+from topen import TConf, build_config
 
 class TestTConf:
     def test_paths_are_expanded(self):
@@ -116,7 +33,68 @@ class TestTConf:
             ({"VISUAL": "nvim", "EDITOR": "notepad"}, "notepad"),
         ],
     )
-    def test_editor_env_resolution(isolate_env, monkeypatch, env, expected):
+    def test_editor_env_resolution(self, isolate_env, monkeypatch, env, expected):
         for k, v in env.items():
             monkeypatch.setenv(k, v)
         assert TConf(0).notes_editor == expected
+
+
+class TestBuildConfigPrecedence:
+    """
+    All tests exercise the same key (notes_ext) to keep the assertions short.
+    Each source sets a different value so we can be sure the right one wins.
+    """
+
+    def test_defaults_only(self, fake_rc, monkeypatch, isolate_env, fake_id):
+        cfg = build_config()
+        assert cfg.notes_ext == "md"
+
+    def test_taskrc_overrides_defaults(
+        self, fake_rc, monkeypatch, isolate_env, fake_id
+    ):
+        fake_rc.write_text("notes.ext=from-rc\n")
+        cfg = build_config()
+        assert cfg.notes_ext == "from-rc"
+
+    def test_env_overrides_taskrc(self, fake_rc, monkeypatch, isolate_env, fake_id):
+        fake_rc.write_text("notes.ext=from-rc\n")
+        monkeypatch.setenv("TOPEN_NOTES_EXT", "from-env")
+        cfg = build_config()
+        assert cfg.notes_ext == "from-env"
+
+    def test_cli_overrides_env(self, fake_rc, monkeypatch, isolate_env):
+        fake_rc.write_text("notes.ext=from-rc\n")
+        monkeypatch.setenv("TOPEN_NOTES_EXT", "from-env")
+        monkeypatch.setattr("sys.argv", ["topen", "0", "--extension", "from-cli"])
+        cfg = build_config()
+        assert cfg.notes_ext == "from-cli"
+
+    def test_cli_overrides_everything(self, fake_rc, monkeypatch, isolate_env):
+        fake_rc.write_text("notes.ext=from-rc\nnotes.dir=/rc-dir\nnotes.editor=joe")
+        monkeypatch.setenv("TOPEN_NOTES_EXT", "from-env")
+        monkeypatch.setenv("TOPEN_NOTES_DIR", "/env-dir")
+        monkeypatch.setenv("EDITOR", "emacs")
+        # CLI wins
+        monkeypatch.setattr(
+            "sys.argv",
+            [
+                "topen",
+                "0",
+                "--extension",
+                "cli-ext",
+                "--notes-dir",
+                "cli-dir",
+                "--editor",
+                "helix",
+            ],
+        )
+        cfg = build_config()
+        assert cfg.notes_ext == "cli-ext"
+        assert cfg.notes_dir == Path("cli-dir")
+        assert cfg.notes_editor == "helix"
+
+    # sanity check that the task-id coming from CLI is preserved
+    def test_cli_supplies_task_id(self, fake_rc, monkeypatch, isolate_env):
+        monkeypatch.setattr("sys.argv", ["topen", "42"])
+        cfg = build_config()
+        assert cfg.task_id == "42"
diff --git a/test/test_parse_cli.py b/test/test_parse_cli.py
new file mode 100644
index 0000000..984dcf5
--- /dev/null
+++ b/test/test_parse_cli.py
@@ -0,0 +1,48 @@
+from pathlib import Path
+
+from topen import parse_cli
+
+
+class TestCli:
+    def test_cli_minimum_id(self, monkeypatch):
+        monkeypatch.setattr("sys.argv", ["topen", "42"])
+        assert parse_cli() == {"task_id": "42"}
+
+    def test_cli_options(self, monkeypatch):
+        monkeypatch.setattr(
+            "sys.argv",
+            [
+                "topen",
+                "123",
+                "--extension",
+                "txt",
+                "--editor",
+                "vim",
+                "--annotation",
+                "HERENOTE",
+            ],
+        )
+        assert parse_cli() == {
+            "task_id": "123",
+            "notes_ext": "txt",
+            "notes_editor": "vim",
+            "notes_annot": "HERENOTE",
+        }
+
+    def test_cli_notes_quiet_is_flag(self, monkeypatch):
+        monkeypatch.setattr(
+            "sys.argv",
+            [
+                "topen",
+                "123",
+                "--quiet",
+            ],
+        )
+        assert parse_cli()["notes_quiet"] is True
+
+    def test_cli_parses_paths(self, monkeypatch):
+        monkeypatch.setattr(
+            "sys.argv",
+            ["topen", "123", "--notes-dir", "/somewhere/else"],
+        )
+        assert parse_cli()["notes_dir"] == Path("/somewhere/else")
diff --git a/test/test_parse_env.py b/test/test_parse_env.py
new file mode 100644
index 0000000..2f637e0
--- /dev/null
+++ b/test/test_parse_env.py
@@ -0,0 +1,35 @@
+from pathlib import Path
+
+from topen import parse_env
+
+
+class TestEnv:
+    def test_env_notes_ext(self, isolate_env, monkeypatch):
+        monkeypatch.setenv("TOPEN_NOTES_DIR", "/blablubb")
+        monkeypatch.setenv("TOPEN_NOTES_EXT", "rst")
+        monkeypatch.setenv("TOPEN_NOTES_ANNOT", "qmd")
+        monkeypatch.setenv("TOPEN_NOTES_EDITOR", "vim")
+        monkeypatch.setenv("TOPEN_NOTES_QUIET", "true")
+        env = parse_env()
+        assert env["notes_dir"] == Path("/blablubb")
+        assert env["notes_ext"] == "rst"
+        assert env["notes_annot"] == "qmd"
+        assert env["notes_editor"] == "vim"
+        assert env["notes_quiet"] is True
+
+    def test_env_task_rc(self, isolate_env, monkeypatch):
+        monkeypatch.setenv("TASKRC", "/a/dir/that/dont/exist/file")
+        monkeypatch.setenv("TASKDATA", "~/somewhere/tasks")
+        env = parse_env()
+        assert env["task_rc"] == Path("/a/dir/that/dont/exist/file")
+        assert env["task_data"] == Path("~/somewhere/tasks")
+
+    def test_env_parses_boolean_true(self, isolate_env, monkeypatch):
+        monkeypatch.setenv("TOPEN_NOTES_QUIET", "true")
+        env = parse_env()
+        assert env["notes_quiet"] is True
+
+    def test_env_parses_boolean_false(self, isolate_env, monkeypatch):
+        monkeypatch.setenv("TOPEN_NOTES_QUIET", "false")
+        env = parse_env()
+        assert env["notes_quiet"] is False
diff --git a/test/test_parse_rc.py b/test/test_parse_rc.py
new file mode 100644
index 0000000..c46b094
--- /dev/null
+++ b/test/test_parse_rc.py
@@ -0,0 +1,36 @@
+from pathlib import Path
+
+from topen import parse_rc
+
+
+class TestRcFile:
+    def test_taskrc_parsing(self, fake_rc):
+        fake_rc.write_text("""
+        data.location=~/.taskies
+        notes.dir=/there
+        notes.ext=yaml
+        notes.annot=Boo!
+        notes.editor=micro
+        notes.quiet=true
+        """)
+        rc_cfg = parse_rc(fake_rc)
+        assert rc_cfg["task_data"] == Path("~/.taskies")
+        assert rc_cfg["notes_dir"] == Path("/there")
+        assert rc_cfg["notes_ext"] == "yaml"
+        assert rc_cfg["notes_annot"] == "Boo!"
+        assert rc_cfg["notes_editor"] == "micro"
+        assert rc_cfg["notes_quiet"] is True
+
+    def test_taskrc_parses_boolean_true(self, fake_rc):
+        fake_rc.write_text("""
+        notes.quiet=true
+        """)
+        rc_cfg = parse_rc(fake_rc)
+        assert rc_cfg["notes_quiet"] is True
+
+    def test_taskrc_parses_boolean_false(self, fake_rc):
+        fake_rc.write_text("""
+        notes.quiet=false
+        """)
+        rc_cfg = parse_rc(fake_rc)
+        assert rc_cfg["notes_quiet"] is False
diff --git a/topen.py b/topen.py
index 611d771..e04e39e 100755
--- a/topen.py
+++ b/topen.py
@@ -23,7 +23,7 @@ import subprocess
 import sys
 from dataclasses import asdict, dataclass
 from pathlib import Path
-from typing import Any, Self, cast
+from typing import Any, Callable, Self, cast
 
 from tasklib import Task, TaskWarrior
 
@@ -130,8 +130,9 @@ class Opt:
     rc: str | None
     default: Any = None
     metavar: str | None = None
-    cast: type = str
+    cast: type | Callable = str
     help_text: str = ""
+    is_flag: bool = False
 
 
 def _real_path(p: Path | str) -> Path:
@@ -146,6 +147,24 @@ def _determine_default_task_rc() -> Path:
     return _real_path("~/.config/task/taskrc")
 
 
+def _strtobool(val: str) -> bool:
+    """Convert a string representation of truth.
+
+    Coverts either to True or False, raising an error if it does not find a
+    valid value.
+    True values are 'y', 'yes', 't', 'true', 'on', and '1'; false values are 'n',
+    'no', 'f', 'false', 'off', and '0'.
+    Raises ValueError if 'val' is anything else.
+    """
+    val = val.lower()
+    if val in ("y", "yes", "t", "true", "on", "1"):
+        return True
+    elif val in ("n", "no", "f", "false", "off", "0"):
+        return False
+    else:
+        raise ValueError(f"Invalid boolean value {val}")
+
+
 OPTIONS: dict[str, Opt] = {
     "task_id": Opt(None, None, None, default=None),
     "task_rc": Opt(
@@ -204,8 +223,9 @@ OPTIONS: dict[str, Opt] = {
         "TOPEN_NOTES_QUIET",
         "notes.quiet",
         default=False,
-        cast=bool,
-        help_text="Silence any verbose displayed information",
+        cast=_strtobool,
+        help_text="Silence any verbosely displayed information",
+        is_flag=True,
     ),
 }
 
@@ -267,17 +287,16 @@ class TConf:
 
 def build_config() -> TConf:
     """Return final configuration object."""
-    cli = parse_cli()
+    defaults = {k: opt.default for k, opt in OPTIONS.items()}
     env = parse_env()
+    cli = parse_cli()
+
     rc_path = Path(
         cli.get("task_rc") or env.get("task_rc") or OPTIONS["task_rc"].default
     ).expanduser()
+    defaults["task_rc"] = rc_path  # use XDG-included paths
     rc = parse_rc(rc_path) if rc_path.exists() else {}
 
-    # we use the 'parsed' XDG-included taskrc locations for defaults
-    defaults = {k: opt.default for k, opt in OPTIONS.items()}
-    defaults["task_rc"] = rc_path
-
     merged = defaults | rc | env | cli  # later wins
     return TConf.from_dict({k: v for k, v in merged.items() if v is not None})
 
@@ -303,6 +322,15 @@ you view the task.
     for key, opt in OPTIONS.items():
         if opt.cli is None:
             continue
+        if opt.is_flag:
+            parser.add_argument(
+                *opt.cli,
+                dest=key,
+                help=opt.help_text,
+                default=None,
+                action="store_true",
+            )
+            continue
         parser.add_argument(
             *opt.cli,
             dest=key,