diff --git a/src/backend/tests/test_vision_boundary.py b/src/backend/tests/test_vision_boundary.py
index b230fa0..7635c8c 100644
--- a/src/backend/tests/test_vision_boundary.py
+++ b/src/backend/tests/test_vision_boundary.py
@@ -8,18 +8,54 @@ import ast
 from pathlib import Path
 
 BACKEND = Path(__file__).resolve().parents[1]
-FORBIDDEN = {"visionsuite", "pm2d", "dxf_compare", "Acquire", "torch"}
+
+# Full dotted prefixes, not bare roots: "src" alone would forbid every import
+# the backend legitimately makes of itself (src.backend.*), so the entries
+# for the vision tree are multi-segment ("src.vision", "src.vision_worker")
+# while VisionSuite's own top-level packages stay single-segment.
+#
+# M2: "Acquire" used to sit here as a stand-in for vs-camera, but it is a
+# class/SDK name (Balluff's "mvIMPACT Acquire" SDK), never an import root -
+# it could never match. vs-camera imports under the same `visionsuite`
+# namespace as vs-core (see
+# vendor/visionsuite/packages/vs-camera/pyproject.toml: "il codice si importa
+# come visionsuite.camera...."), which "visionsuite" below already forbids,
+# so there is nothing separate to add for it.
+FORBIDDEN = {
+    "visionsuite", "pm2d", "dxf_compare", "torch",
+    "src.vision", "src.vision_worker",
+}
 
 
-def _imported_roots(source: Path) -> set[str]:
+def _imported_modules(source: Path) -> set[str]:
+    """Full dotted module paths this file imports - not just their first
+    segment. `from src.vision.runner import ...` must be checked against
+    "src.vision.runner" (inside the forbidden "src.vision"), not against
+    "src" alone, which is never forbidden since the backend imports itself
+    constantly.
+    """
     tree = ast.parse(source.read_text(encoding="utf-8"), filename=str(source))
-    roots: set[str] = set()
+    modules: set[str] = set()
     for node in ast.walk(tree):
         if isinstance(node, ast.Import):
-            roots.update(alias.name.split(".")[0] for alias in node.names)
+            modules.update(alias.name for alias in node.names)
         elif isinstance(node, ast.ImportFrom) and node.module and node.level == 0:
-            roots.add(node.module.split(".")[0])
-    return roots
+            modules.add(node.module)
+    return modules
+
+
+def _forbidden_hits(modules: set[str]) -> set[str]:
+    """Which FORBIDDEN entries a set of imported module paths triggers.
+
+    A module counts as forbidden if it equals a forbidden entry exactly, or
+    lives inside it ("src.vision.runner" is inside "src.vision").
+    """
+    hits: set[str] = set()
+    for module in modules:
+        for entry in FORBIDDEN:
+            if module == entry or module.startswith(entry + "."):
+                hits.add(entry)
+    return hits
 
 
 def test_the_server_never_imports_visionsuite():
@@ -27,7 +63,7 @@ def test_the_server_never_imports_visionsuite():
     for source in BACKEND.rglob("*.py"):
         if "tests" in source.parts or "migrations" in source.parts:
             continue
-        forbidden = _imported_roots(source) & FORBIDDEN
+        forbidden = _forbidden_hits(_imported_modules(source))
         if forbidden:
             offenders.append(f"{source.relative_to(BACKEND)}: {sorted(forbidden)}")
 
@@ -42,3 +78,29 @@ def test_the_submodule_is_pinned():
     gitmodules = Path(__file__).resolve().parents[3] / ".gitmodules"
     assert gitmodules.exists(), "vendor/visionsuite non è un sottomodulo"
     assert "vendor/visionsuite" in gitmodules.read_text(encoding="utf-8")
+
+
+def test_a_full_module_path_import_is_caught_not_just_its_root(tmp_path):
+    """M2: `from src.vision.runner import ...` inside src/backend/** must be
+    caught. Checking only the first dotted segment ("src") would miss it -
+    "src" itself is never forbidden, the backend imports itself all the time.
+    This is the blind spot the reviewer found: same repository, no install
+    needed, the most tempting shortcut of all.
+    """
+    offender = tmp_path / "sneaky.py"
+    offender.write_text("from src.vision.runner import run_graph\n")
+    assert _forbidden_hits(_imported_modules(offender)) == {"src.vision"}
+
+
+def test_a_vision_worker_import_is_also_caught(tmp_path):
+    offender = tmp_path / "sneaky.py"
+    offender.write_text("import src.vision_worker.main\n")
+    assert _forbidden_hits(_imported_modules(offender)) == {"src.vision_worker"}
+
+
+def test_an_unrelated_src_backend_import_is_not_caught(tmp_path):
+    """The fix must not turn every self-import of the backend into an
+    offender - only the vision subtrees are forbidden."""
+    innocent = tmp_path / "innocent.py"
+    innocent.write_text("from src.backend.config import settings\n")
+    assert _forbidden_hits(_imported_modules(innocent)) == set()