diff --git a/tests/unit/test_small_domain_modules.py b/tests/unit/test_small_domain_modules.py
new file mode 100644
index 000000000..e4516e39e
--- /dev/null
+++ b/tests/unit/test_small_domain_modules.py
@@ -0,0 +1,377 @@
+"""小领域模块组合单测 — template_clip_config / tag / exceptions / editing_mode."""
+
+from __future__ import annotations
+
+import pytest
+
+from packages.domain.editing_mode import EditingMode
+from packages.domain.exceptions import (
+    DomainError,
+    NotFoundError,
+    QuotaExceededError,
+    ValidationError,
+)
+from packages.domain.tag import Tag
+from packages.domain.template_clip_config import (
+    ClipType,
+    TemplateClipConfig,
+    TransitionEffect,
+)
+
+
+# ── EditingMode ────────────────────────────────────────────────────────────
+
+
+class TestEditingMode:
+    def test_one_take(self):
+        assert EditingMode.ONE_TAKE == "one_take"
+
+    def test_pip(self):
+        assert EditingMode.PIP == "pip"
+
+    def test_voice_over(self):
+        assert EditingMode.VOICE_OVER == "voice_over"
+
+    def test_voice_pip(self):
+        assert EditingMode.VOICE_PIP == "voice_pip"
+
+    def test_from_string(self):
+        assert EditingMode("one_take") == EditingMode.ONE_TAKE
+        assert EditingMode("pip") == EditingMode.PIP
+
+    def test_invalid_raises(self):
+        with pytest.raises(ValueError):
+            EditingMode("invalid_mode")
+
+    def test_is_str(self):
+        # StrEnum 实例本身就是 str
+        assert isinstance(EditingMode.ONE_TAKE, str)
+        assert EditingMode.ONE_TAKE + "_suffix" == "one_take_suffix"
+
+
+# ── 异常类 ─────────────────────────────────────────────────────────────────
+
+
+class TestExceptions:
+    def test_domain_error_is_exception(self):
+        err = DomainError("test")
+        assert isinstance(err, Exception)
+        assert str(err) == "test"
+
+    def test_not_found_inherits_domain(self):
+        err = NotFoundError("not found")
+        assert isinstance(err, DomainError)
+        assert str(err) == "not found"
+
+    def test_validation_error_inherits_domain(self):
+        err = ValidationError("bad input")
+        assert isinstance(err, DomainError)
+        assert str(err) == "bad input"
+
+    def test_quota_exceeded_error_attributes(self):
+        err = QuotaExceededError(dimension="storage_gb", limit=100, used=150)
+        assert err.dimension == "storage_gb"
+        assert err.limit == 100
+        assert err.used == 150
+        assert "storage_gb" in str(err)
+        assert "150" in str(err)
+        assert "100" in str(err)
+
+    def test_quota_exceeded_is_domain_error(self):
+        err = QuotaExceededError("x", 10, 20)
+        assert isinstance(err, DomainError)
+
+    def test_catch_domain_error_catches_all(self):
+        """所有领域异常都能被 DomainError catch."""
+        for cls in [NotFoundError, ValidationError, QuotaExceededError]:
+            try:
+                if cls == QuotaExceededError:
+                    raise cls("dim", 10, 20)
+                raise cls("msg")
+            except DomainError:
+                pass
+            else:
+                pytest.fail(f"{cls.__name__} 未被 DomainError 捕获")
+
+
+# ── Tag ────────────────────────────────────────────────────────────────────
+
+
+class TestTag:
+    def test_create_basic(self):
+        tag = Tag.create(user_id="user1", name="旅行")
+        assert tag.id
+        assert tag.user_id == "user1"
+        assert tag.name == "旅行"
+
+    def test_create_name_stripped(self):
+        tag = Tag.create(user_id="u1", name="  美食  ")
+        assert tag.name == "美食"
+
+    def test_create_empty_name_raises(self):
+        with pytest.raises(ValueError, match="标签名称不能为空"):
+            Tag.create(user_id="u1", name="")
+
+    def test_create_whitespace_name_raises(self):
+        with pytest.raises(ValueError, match="标签名称不能为空"):
+            Tag.create(user_id="u1", name="   ")
+
+    def test_create_has_created_at(self):
+        tag = Tag.create(user_id="u1", name="t1")
+        assert tag.created_at is not None
+
+    def test_unique_ids(self):
+        t1 = Tag.create(user_id="u1", name="t1")
+        t2 = Tag.create(user_id="u1", name="t2")
+        assert t1.id != t2.id
+
+
+# ── ClipType 枚举 ─────────────────────────────────────────────────────────
+
+
+class TestClipType:
+    def test_all_types(self):
+        assert ClipType.INTRO == "intro"
+        assert ClipType.MAIN == "main"
+        assert ClipType.TRANSITION == "transition"
+        assert ClipType.OUTRO == "outro"
+        assert ClipType.TITLE == "title"
+        assert ClipType.SUBTITLE == "subtitle"
+
+    def test_from_string(self):
+        assert ClipType("main") == ClipType.MAIN
+        assert ClipType("intro") == ClipType.INTRO
+
+    def test_invalid_raises(self):
+        with pytest.raises(ValueError):
+            ClipType("invalid")
+
+
+# ── TransitionEffect 枚举 ─────────────────────────────────────────────────
+
+
+class TestTransitionEffect:
+    def test_all_effects(self):
+        assert TransitionEffect.CUT == "cut"
+        assert TransitionEffect.FADE == "fade"
+        assert TransitionEffect.SLIDE_LEFT == "slide_left"
+        assert TransitionEffect.SLIDE_RIGHT == "slide_right"
+        assert TransitionEffect.DISSOLVE == "dissolve"
+        assert TransitionEffect.WIPE == "wipe"
+
+    def test_from_string(self):
+        assert TransitionEffect("fade") == TransitionEffect.FADE
+        assert TransitionEffect("cut") == TransitionEffect.CUT
+
+    def test_invalid_raises(self):
+        with pytest.raises(ValueError):
+            TransitionEffect("invalid_effect")
+
+
+# ── TemplateClipConfig.create ──────────────────────────────────────────────
+
+
+class TestTemplateClipConfigCreate:
+    def test_basic_creation(self):
+        clip = TemplateClipConfig.create(
+            template_id="tmpl_1",
+            clip_type=ClipType.MAIN,
+            order=1,
+        )
+        assert clip.id
+        assert clip.template_id == "tmpl_1"
+        assert clip.clip_type == ClipType.MAIN
+        assert clip.order == 1
+        assert clip.min_duration == 0.0
+        assert clip.max_duration == 0.0
+        assert clip.text_template == ""
+        assert clip.material_requirements == {}
+        assert clip.transition_effect == TransitionEffect.CUT
+        assert clip.config == {}
+
+    def test_clip_type_string(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type="intro", order=0,
+        )
+        assert clip.clip_type == ClipType.INTRO
+
+    def test_template_id_stripped(self):
+        clip = TemplateClipConfig.create(
+            template_id="  tmpl_1  ", clip_type=ClipType.MAIN, order=1,
+        )
+        assert clip.template_id == "tmpl_1"
+
+    def test_empty_template_id_raises(self):
+        with pytest.raises(ValueError, match="template_id 不能为空"):
+            TemplateClipConfig.create(template_id="", clip_type=ClipType.MAIN, order=1)
+
+    def test_whitespace_template_id_raises(self):
+        with pytest.raises(ValueError, match="template_id 不能为空"):
+            TemplateClipConfig.create(template_id="  ", clip_type=ClipType.MAIN, order=1)
+
+    def test_negative_min_duration_raises(self):
+        with pytest.raises(ValueError, match="min_duration 不能为负数"):
+            TemplateClipConfig.create(
+                template_id="t1", clip_type=ClipType.MAIN, order=1,
+                min_duration=-1.0,
+            )
+
+    def test_negative_max_duration_raises(self):
+        with pytest.raises(ValueError, match="max_duration 不能为负数"):
+            TemplateClipConfig.create(
+                template_id="t1", clip_type=ClipType.MAIN, order=1,
+                max_duration=-1.0,
+            )
+
+    def test_min_greater_than_max_raises(self):
+        with pytest.raises(ValueError, match="min_duration 不能大于 max_duration"):
+            TemplateClipConfig.create(
+                template_id="t1", clip_type=ClipType.MAIN, order=1,
+                min_duration=10.0, max_duration=5.0,
+            )
+
+    def test_zero_min_and_max_ok(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=0, max_duration=0,
+        )
+        assert clip.min_duration == 0
+        assert clip.max_duration == 0
+
+    def test_min_zero_max_positive_ok(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=0, max_duration=10.0,
+        )
+        assert clip.max_duration == 10.0
+
+    def test_min_equals_max_ok(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=5.0, max_duration=5.0,
+        )
+        assert clip.min_duration == 5.0
+        assert clip.max_duration == 5.0
+
+    def test_with_text_template(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            text_template="  欢迎收看 {channel}  ",
+        )
+        # text_template 会 strip
+        assert clip.text_template == "欢迎收看 {channel}"
+
+    def test_with_material_requirements(self):
+        reqs = {"material_type": "video", "min_duration": 3}
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            material_requirements=reqs,
+        )
+        assert clip.material_requirements == reqs
+
+    def test_material_requirements_none_defaults_empty(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            material_requirements=None,
+        )
+        assert clip.material_requirements == {}
+
+    def test_transition_effect_string(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            transition_effect="fade",
+        )
+        assert clip.transition_effect == TransitionEffect.FADE
+
+    def test_with_config(self):
+        config = {"speed": 1.5, "filter": "vibrance"}
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            config=config,
+        )
+        assert clip.config == config
+
+    def test_config_none_defaults_empty(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            config=None,
+        )
+        assert clip.config == {}
+
+    def test_created_at_and_updated_at(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+        )
+        assert clip.created_at is not None
+        assert clip.updated_at is not None
+
+    def test_unique_ids(self):
+        c1 = TemplateClipConfig.create(template_id="t1", clip_type=ClipType.MAIN, order=1)
+        c2 = TemplateClipConfig.create(template_id="t1", clip_type=ClipType.MAIN, order=2)
+        assert c1.id != c2.id
+
+
+# ── TemplateClipConfig 属性 ────────────────────────────────────────────────
+
+
+class TestTemplateClipConfigProperties:
+    def test_has_duration_range_false_both_zero(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+        )
+        assert clip.has_duration_range is False
+
+    def test_has_duration_range_true_min_only(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=2.0,
+        )
+        assert clip.has_duration_range is True
+
+    def test_has_duration_range_true_max_only(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            max_duration=10.0,
+        )
+        assert clip.has_duration_range is True
+
+    def test_has_duration_range_true_both_set(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=2.0, max_duration=10.0,
+        )
+        assert clip.has_duration_range is True
+
+    def test_default_duration_zero(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+        )
+        assert clip.default_duration == 0.0
+
+    def test_default_duration_min_only(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=3.0,
+        )
+        assert clip.default_duration == 3.0
+
+    def test_default_duration_max_only(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            max_duration=10.0,
+        )
+        assert clip.default_duration == 10.0
+
+    def test_default_duration_both_midpoint(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=2.0, max_duration=8.0,
+        )
+        assert clip.default_duration == 5.0
+
+    def test_default_duration_min_equals_max(self):
+        clip = TemplateClipConfig.create(
+            template_id="t1", clip_type=ClipType.MAIN, order=1,
+            min_duration=5.0, max_duration=5.0,
+        )
+        assert clip.default_duration == 5.0