[eric] skills: an unrelated npx paste no longer installs a skill named after it

backend/apps/skill_registry/parse_install_command.py

@@ -41,11 +41,17 @@ def parse_install_command(raw: str) -> Optional[str]:
         rest = [t for t in tokens[1:] if not t.startswith("-")]
         # The verb and the package name arrive in either order ("npx skills add x", "npm i skills x"),
         # so strip both, in whichever order they appear.
+        named_registry = False
         for _ in range(2):
             if rest and rest[0].lower() in ("skills", "skill", "@skills/cli", "openswarm"):
                 rest = rest[1:]
+                named_registry = True
             elif rest and rest[0].lower() in P_VERBS:
                 rest = rest[1:]
+        # Without the registry name this is just some other npx command, and `npx create-react-app foo`
+        # must never read as "install the create-react-app skill".
+        if not named_registry:
+            return None
         candidate = rest[0] if rest else ""
         return candidate if candidate and P_SKILL_ID.match(candidate) else None
 

backend/tests/test_parse_install_command_refusals.py

@@ -0,0 +1,40 @@
+"""A paste that is not a skills install must return None, not a guess.
+
+`npx create-react-app foo` parsed as the skill id "create-react-app" until 2026-08-07: any unrelated
+npx command a user pasted would have installed a skill by that name. The module's own docstring says
+None means "I could not read this", never a guess, so the registry name is now required."""
+
+import pytest
+
+from backend.apps.skill_registry.parse_install_command import parse_install_command
+
+REAL_INSTALLS = [
+    ("npx skills add pdf-filler", "pdf-filler"),
+    ("$ npx skills add pdf-filler", "pdf-filler"),
+    ("npm i skills pdf-filler", "pdf-filler"),
+    ("bunx skills install pdf-filler", "pdf-filler"),
+    ("pnpm skills add @acme/pdf-filler", "@acme/pdf-filler"),
+    ("npx skills add pdf-filler --force", "pdf-filler"),
+    ("https://skills.sh/s/pdf-filler", "pdf-filler"),
+    ("pdf-filler", "pdf-filler"),
+]
+
+NOT_INSTALLS = [
+    "npx create-react-app foo",
+    "npm i lodash",
+    "npx vite build",
+    "yarn add react",
+    "rm -rf /",
+    "",
+    "   ",
+]
+
+
+@pytest.mark.parametrize("raw,expected", REAL_INSTALLS)
+def test_the_forms_people_actually_paste_still_parse(raw, expected):
+    assert parse_install_command(raw) == expected
+
+
+@pytest.mark.parametrize("raw", NOT_INSTALLS)
+def test_anything_that_is_not_a_skills_install_is_refused(raw):
+    assert parse_install_command(raw) is None, f"{raw!r} must not be read as a skill id"