fix: use description as pattern_key to prevent approval collisions

pattern_key was derived by splitting the regex on \b and taking [1],
so patterns starting with the same word (e.g. find -exec rm and
find -delete) produced the same key "find". Approving one silently
approved the other. Using the unique description string as the key
eliminates all collisions.

tests/tools/test_approval.py

@@ -342,6 +342,33 @@ class TestFindExecFullPathRm:
         assert key is None
 
 
+class TestPatternKeyUniqueness:
+    """Bug: pattern_key is derived by splitting on \\b and taking [1], so
+    patterns starting with the same word (e.g. find -exec rm and find -delete)
+    produce the same key. Approving one silently approves the other."""
+
+    def test_find_exec_rm_and_find_delete_have_different_keys(self):
+        _, key_exec, _ = detect_dangerous_command("find . -exec rm {} \\;")
+        _, key_delete, _ = detect_dangerous_command("find . -name '*.tmp' -delete")
+        assert key_exec != key_delete, (
+            f"find -exec rm and find -delete share key {key_exec!r} — "
+            "approving one silently approves the other"
+        )
+
+    def test_approving_find_exec_does_not_approve_find_delete(self):
+        """Session approval for find -exec rm must not carry over to find -delete."""
+        _, key_exec, _ = detect_dangerous_command("find . -exec rm {} \\;")
+        _, key_delete, _ = detect_dangerous_command("find . -name '*.tmp' -delete")
+        session = "test_find_collision"
+        clear_session(session)
+        approve_session(session, key_exec)
+        assert is_approved(session, key_exec) is True
+        assert is_approved(session, key_delete) is False, (
+            "approving find -exec rm should not auto-approve find -delete"
+        )
+        clear_session(session)
+
+
 class TestViewFullCommand:
     """Tests for the 'view full command' option in prompt_dangerous_approval."""
 

tools/approval.py

@@ -63,7 +63,7 @@ def detect_dangerous_command(command: str) -> tuple:
     command_lower = command.lower()
     for pattern, description in DANGEROUS_PATTERNS:
         if re.search(pattern, command_lower, re.IGNORECASE | re.DOTALL):
-            pattern_key = pattern.split(r'\b')[1] if r'\b' in pattern else pattern[:20]
+            pattern_key = description
             return (True, pattern_key, description)
     return (False, None, None)