diff --git a/CHANGELOG.md b/CHANGELOG.md
index 118c80c..34f3436 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,9 +8,10 @@ Contributors add user-facing entries under `[Unreleased]` in the same PR. Mainta
 
 ## [Unreleased]
 
-### Documentation
+### Changed
 
-- Clarified that bundle tests must mock network calls and model downloads in CI.
+- **Tests**: `tests/test_skill_issuer.py` now requires `test_skill.py` for every registry skill under `skills/` (#160).
+- **Documentation**: Clarified that bundle tests must mock network calls and model downloads in CI (#170).
 
 ## [0.3.7] - 2026-06-22
 
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 9f5b639..e74a081 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -252,7 +252,7 @@ The primary guide for the host LLM.
 
 ### 5. `test_skill.py` (bundle test)
 
-- **Required** for every new registry skill (template: `templates/python_skill/test_skill.py`).
+- **Required** for every new registry skill (template: `templates/python_skill/test_skill.py`; enforced by `tests/test_skill_issuer.py`).
 - Unit tests for schema compliance and deterministic execution paths (offline; mock externals).
 - Ships inside the skill bundle via `pip install skillware`.
 - Run: `pytest skills/<category>/<skill_name>/test_skill.py`
diff --git a/docs/TESTING.md b/docs/TESTING.md
index d7b08a8..f86959b 100644
--- a/docs/TESTING.md
+++ b/docs/TESTING.md
@@ -41,6 +41,7 @@ pip install -r requirements.txt
 ### Framework test
 
 - Core engine health: loader, CLI, issuer rules, version policy.
+- `tests/test_skill_issuer.py` also enforces registry packaging (`__init__.py`), issuer metadata, and presence of `test_skill.py` in every skill bundle.
 - Lives at the **root of `tests/`** only (`tests/test_loader.py`, `tests/test_cli.py`, …).
 - Clone-repo only; runs in CI via `pytest tests/` together with maintainer tests below.
 
diff --git a/templates/python_skill/README.md b/templates/python_skill/README.md
index 3e60bda..2e43528 100644
--- a/templates/python_skill/README.md
+++ b/templates/python_skill/README.md
@@ -10,7 +10,7 @@ Starter bundle under `skills/<category>/<skill_name>/`. Copy this template from
 4. **`skill.py`**: Implement deterministic logic; no LLM-generated code in the skill body.
 5. **`instructions.md`**: Tell the agent when and how to use the tool.
 6. **`card.json`**: Mirror `issuer` from the manifest; customize UI fields.
-7. **`test_skill.py`**: Bundle test (required); offline, mock external services, including HTTP clients, LLM APIs, embedding/model loaders, and any first-run model downloads; run `pytest skills/<category>/<skill_name>/test_skill.py`. See [TESTING.md](../../docs/TESTING.md).
+7. **`test_skill.py`**: Bundle test (required; enforced by `tests/test_skill_issuer.py`); offline, mock external services, including HTTP clients, LLM APIs, embedding/model loaders, and any first-run model downloads; run `pytest skills/<category>/<skill_name>/test_skill.py`. See [TESTING.md](../../docs/TESTING.md).
 8. **`docs/skills/<skill_name>.md`**: Catalog page with **ID**, **Issuer**, and **Usage Examples** (all providers; see `docs/usage/skill_usage_template.md`).
 9. **`docs/skills/README.md`**: Add a row to the skill library table.
 
diff --git a/tests/test_skill_issuer.py b/tests/test_skill_issuer.py
index 8c1fd14..c130033 100644
--- a/tests/test_skill_issuer.py
+++ b/tests/test_skill_issuer.py
@@ -64,6 +64,17 @@ def test_registry_skills_declare_issuer():
         _assert_real_issuer(manifest.get("issuer"), f"{rel} manifest.yaml")
 
 
+def test_registry_skills_have_bundle_test():
+    """Every registry skill must ship a co-located bundle test (RFC #156)."""
+    for skill_dir in _discover_skill_dirs():
+        rel = skill_dir.relative_to(REPO_ROOT).as_posix()
+        assert (
+            skill_dir / "test_skill.py"
+        ).is_file(), (
+            f"{rel}: add test_skill.py (bundle test required for every registry skill)"
+        )
+
+
 def test_registry_skills_have_packaging_init_files():
     """Each registry skill must be importable under the skills package for pip wheels."""
     assert (