diff --git a/tools/command_builder/tests/test_schema.py b/tools/command_builder/tests/test_schema.py
new file mode 100644
index 0000000..0182560
--- /dev/null
+++ b/tools/command_builder/tests/test_schema.py
@@ -0,0 +1,263 @@
+from __future__ import annotations
+
+import io
+from pathlib import Path
+
+import pytest
+from ruamel.yaml import YAML
+
+from tools.command_builder.schema import (
+    CommandEntry,
+    ExeAction,
+    KeysAction,
+    MultiAction,
+    PlaySoundAction,
+    SchemaError,
+    ShellAction,
+    SleepAction,
+    SystemAction,
+    UrlAction,
+    action_from_dict,
+    command_from_dict,
+    slugify,
+)
+from tools.command_builder.yaml_writer import (
+    append_command,
+    load_yaml,
+    upsert_command,
+)
+
+
+def _roundtrip(action_obj):
+    d = action_obj.to_dict()
+    y = YAML()
+    buf = io.StringIO()
+    y.dump(d, buf)
+    buf.seek(0)
+    loaded = y.load(buf)
+    return action_from_dict(dict(loaded))
+
+
+def test_exe_roundtrip():
+    a = ExeAction(file="Run browser.exe", wait=True, delay_ms=200)
+    b = _roundtrip(a)
+    assert b.file == a.file and b.wait is True and b.delay_ms == 200
+
+
+def test_exe_minimal():
+    a = ExeAction(file="x.exe")
+    b = _roundtrip(a)
+    assert b.file == "x.exe" and b.wait is None and b.delay_ms is None
+
+
+def test_play_sound_roundtrip():
+    a = PlaySoundAction(name="ok")
+    b = _roundtrip(a)
+    assert b.name == "ok"
+
+
+def test_play_sound_rejects_unknown():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "play_sound", "name": "nope"})
+
+
+def test_system_roundtrip():
+    for op in ("volume_mute", "volume_unmute", "exit"):
+        a = SystemAction(op=op)
+        b = _roundtrip(a)
+        assert b.op == op
+
+
+def test_system_rejects_unknown_op():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "system", "op": "reboot"})
+
+
+def test_sleep_roundtrip():
+    a = SleepAction(ms=1500)
+    b = _roundtrip(a)
+    assert b.ms == 1500
+
+
+def test_sleep_rejects_negative():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "sleep", "ms": -1})
+
+
+def test_shell_roundtrip():
+    a = ShellAction(cmd="echo hello", wait=True)
+    b = _roundtrip(a)
+    assert b.cmd == "echo hello" and b.wait is True
+
+
+def test_shell_minimal():
+    a = ShellAction(cmd="echo x")
+    b = _roundtrip(a)
+    assert b.wait is None
+
+
+def test_shell_requires_cmd():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "shell"})
+
+
+def test_url_roundtrip():
+    a = UrlAction(href="https://example.com")
+    b = _roundtrip(a)
+    assert b.href == "https://example.com"
+
+
+def test_url_requires_href():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "url"})
+
+
+def test_keys_sequence_roundtrip():
+    a = KeysAction(sequence="ctrl+shift+m")
+    b = _roundtrip(a)
+    assert b.sequence == "ctrl+shift+m" and b.text is None
+
+
+def test_keys_text_roundtrip():
+    a = KeysAction(text="hello world")
+    b = _roundtrip(a)
+    assert b.text == "hello world" and b.sequence is None
+
+
+def test_keys_requires_one_of():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "keys"})
+
+
+def test_keys_rejects_both():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "keys", "sequence": "ctrl+c", "text": "x"})
+
+
+def test_multi_roundtrip():
+    a = MultiAction(steps=[
+        PlaySoundAction(name="ok"),
+        ExeAction(file="x.exe", wait=True),
+        SleepAction(ms=500),
+        UrlAction(href="https://example.com"),
+        KeysAction(sequence="ctrl+s"),
+        ShellAction(cmd="dir"),
+        SystemAction(op="volume_mute"),
+    ])
+    b = _roundtrip(a)
+    assert isinstance(b, MultiAction)
+    assert len(b.steps) == 7
+    assert isinstance(b.steps[0], PlaySoundAction)
+    assert isinstance(b.steps[4], KeysAction)
+    assert b.steps[4].sequence == "ctrl+s"
+
+
+def test_unknown_type_rejected():
+    with pytest.raises(SchemaError):
+        action_from_dict({"type": "wat"})
+
+
+def test_command_entry_roundtrip():
+    entry = CommandEntry(
+        cmd_id="open_site",
+        phrases=["открой сайт", "открой пример"],
+        action=UrlAction(href="https://example.com"),
+    )
+    d = entry.to_dict()
+    restored = command_from_dict("open_site", d)
+    assert restored.cmd_id == "open_site"
+    assert restored.phrases == ["открой сайт", "открой пример"]
+    assert isinstance(restored.action, UrlAction)
+    assert restored.action.href == "https://example.com"
+
+
+def test_command_requires_phrases():
+    with pytest.raises(SchemaError):
+        command_from_dict("x", {"phrases": [], "action": {"type": "system", "op": "exit"}})
+
+
+def test_slugify_russian():
+    assert slugify("Открой Браузер") == "otkroy_brauzer"
+    assert slugify("hello world") == "hello_world"
+    assert slugify("   ") == "cmd"
+
+
+def _write_fixture(path: Path) -> None:
+    path.write_text(
+        "existing_cmd:\n"
+        "  phrases:\n"
+        "    - пример\n"
+        "  action: {type: play_sound, name: ok}\n"
+        "\n"
+        "another:\n"
+        "  phrases:\n"
+        "    - другой\n"
+        "  action: {type: system, op: exit}\n",
+        encoding="utf-8",
+    )
+
+
+def test_append_writes_and_creates_backup(tmp_path):
+    yaml_path = tmp_path / "commands.yaml"
+    _write_fixture(yaml_path)
+    original = yaml_path.read_text(encoding="utf-8")
+    entry = CommandEntry(
+        cmd_id="open_docs",
+        phrases=["открой доки", "документация"],
+        action=UrlAction(href="https://docs.example.com"),
+    )
+    append_command(entry, path=yaml_path)
+    bak = yaml_path.with_suffix(yaml_path.suffix + ".bak")
+    assert bak.exists()
+    assert bak.read_text(encoding="utf-8") == original
+    data = load_yaml(yaml_path)
+    assert "open_docs" in data
+    assert "existing_cmd" in data
+    assert data["open_docs"]["action"]["href"] == "https://docs.example.com"
+
+
+def test_append_rejects_duplicate_id(tmp_path):
+    yaml_path = tmp_path / "commands.yaml"
+    _write_fixture(yaml_path)
+    entry = CommandEntry(
+        cmd_id="existing_cmd",
+        phrases=["дубликат"],
+        action=SystemAction(op="exit"),
+    )
+    with pytest.raises(SchemaError):
+        append_command(entry, path=yaml_path)
+
+
+def test_upsert_overwrites(tmp_path):
+    yaml_path = tmp_path / "commands.yaml"
+    _write_fixture(yaml_path)
+    entry = CommandEntry(
+        cmd_id="existing_cmd",
+        phrases=["обновлено"],
+        action=SystemAction(op="volume_mute"),
+    )
+    upsert_command(entry, path=yaml_path)
+    data = load_yaml(yaml_path)
+    assert data["existing_cmd"]["action"]["op"] == "volume_mute"
+
+
+def test_ruamel_preserves_inline_comments(tmp_path):
+    yaml_path = tmp_path / "commands.yaml"
+    yaml_path.write_text(
+        "# header comment about commands\n"
+        "open_browser:\n"
+        "  phrases:\n"
+        "    - открой браузер\n"
+        "  action: {type: exe, file: \"Run browser.exe\"}  # inline note\n",
+        encoding="utf-8",
+    )
+    entry = CommandEntry(
+        cmd_id="open_new",
+        phrases=["новое"],
+        action=UrlAction(href="https://new.example.com"),
+    )
+    append_command(entry, path=yaml_path)
+    text = yaml_path.read_text(encoding="utf-8")
+    assert "# header comment about commands" in text
+    assert "# inline note" in text
+    assert "open_new" in text
diff --git a/tools/command_builder/yaml_writer.py b/tools/command_builder/yaml_writer.py
new file mode 100644
index 0000000..17bf278
--- /dev/null
+++ b/tools/command_builder/yaml_writer.py
@@ -0,0 +1,91 @@
+from __future__ import annotations
+
+import io
+import os
+import shutil
+from pathlib import Path
+from typing import Optional
+
+from ruamel.yaml import YAML
+
+from .schema import CommandEntry, SchemaError, command_from_dict
+
+
+DEFAULT_YAML_PATH = Path("C:/Jarvis/python/commands.yaml")
+
+
+def _make_yaml() -> YAML:
+    y = YAML()
+    y.preserve_quotes = True
+    y.indent(mapping=2, sequence=4, offset=2)
+    y.width = 4096
+    return y
+
+
+def load_yaml(path: Path = DEFAULT_YAML_PATH):
+    y = _make_yaml()
+    with open(path, "rt", encoding="utf-8") as f:
+        return y.load(f) or {}
+
+
+def list_command_ids(path: Path = DEFAULT_YAML_PATH) -> list:
+    try:
+        data = load_yaml(path)
+    except FileNotFoundError:
+        return []
+    return list(data.keys())
+
+
+def _dump_to_string(data) -> str:
+    y = _make_yaml()
+    buf = io.StringIO()
+    y.dump(data, buf)
+    return buf.getvalue()
+
+
+def _atomic_write(path: Path, text: str) -> None:
+    tmp = path.with_suffix(path.suffix + ".tmp")
+    with open(tmp, "wt", encoding="utf-8", newline="\n") as f:
+        f.write(text)
+    os.replace(tmp, path)
+
+
+def _backup(path: Path) -> Optional[Path]:
+    if not path.exists():
+        return None
+    bak = path.with_suffix(path.suffix + ".bak")
+    shutil.copy2(path, bak)
+    return bak
+
+
+def append_command(entry: CommandEntry, path: Path = DEFAULT_YAML_PATH) -> None:
+    try:
+        data = load_yaml(path)
+    except FileNotFoundError:
+        data = {}
+    if entry.cmd_id in data:
+        raise SchemaError(f"command id already exists: {entry.cmd_id}")
+    data[entry.cmd_id] = entry.to_dict()
+    _backup(path)
+    text = _dump_to_string(data)
+    _atomic_write(path, text)
+
+
+def upsert_command(entry: CommandEntry, path: Path = DEFAULT_YAML_PATH) -> None:
+    try:
+        data = load_yaml(path)
+    except FileNotFoundError:
+        data = {}
+    data[entry.cmd_id] = entry.to_dict()
+    _backup(path)
+    text = _dump_to_string(data)
+    _atomic_write(path, text)
+
+
+def validate_file(path: Path = DEFAULT_YAML_PATH) -> list:
+    data = load_yaml(path)
+    out = []
+    for cmd_id, body in data.items():
+        plain_body = body
+        out.append(command_from_dict(cmd_id, dict(plain_body)))
+    return out