chore(semantics): lock two inventory ratchets and disclose budget slack

examples/semantic-vocabulary-drift-smoke.py

@@ -147,8 +147,8 @@
 BUDGET_ANCHOR = {
     "same_runtime_forks": 18,
     "same_runtime_fork_definitions": 41,
-    "conflicting_values": 18,
-    "conflicting_definitions": 59,
+    "conflicting_values": 16,
+    "conflicting_definitions": 55,
     "schema_version_same_runtime_forks": 7,
     "multi_value_twins": 13,
     "multi_value_forks": 4,
@@ -692,9 +692,17 @@ def check_inventory(registry: dict[str, Any], sources: list[SourceFile]) -> tupl
                  for item in review['magnitude_regressions']]
     require(review['ok'], '; '.join(failures))
     parts = []
+    slack = []
     for key in RATCHET_KEYS:
         actual = semantic_multi_value_forks if key == "multi_value_forks_semantic" else summary[key]
         parts.append(f"{key}={actual}/{ratchets[key]}")
+        if ratchets[key] > actual:
+            # Disclose unlocked headroom so a merge that reverts a tightened
+            # budget shows up as new slack in this line instead of passing
+            # silently (the guard only fails on overflow, never on slack).
+            slack.append(f"{key}={ratchets[key] - actual}")
+    if slack:
+        parts.append("slack=" + ",".join(slack))
     if review['reviewed_exception_count']:
         parts.append(f"reviewed_inventory_exceptions={review['reviewed_exception_count']}")
     return inventory, " ".join(parts)

loopx/semantics/vocabulary_v0.json

@@ -949,8 +949,8 @@
     "meaning": "Counts read from the generated inventory. A same-runtime fork is one constant name with one value defined in two or more modules of the same runtime; a conflicting value is one name with different values. Both the number of affected names and the number of definitions are budgets, so a third spelling of an already-conflicting name is still a regression.",
     "same_runtime_forks": 18,
     "same_runtime_fork_definitions": 41,
-    "conflicting_values": 18,
-    "conflicting_definitions": 59,
+    "conflicting_values": 16,
+    "conflicting_definitions": 55,
     "schema_version_same_runtime_forks": 7,
     "multi_value_twins": 13,
     "multi_value_forks": 4,
@@ -986,4 +986,4 @@
       ]
     }
   }
-}
+}

tests/architecture/test_semantic_vocabulary_drift.py

@@ -432,3 +432,34 @@ def test_remaining_kernel_values_each_carry_a_note(name):
         if not str(notes.get(value) or '').strip()
     ]
     assert not undocumented, f'{name}: values with no value_notes entry: {undocumented}'
+
+
+def test_inventory_report_discloses_budget_slack(monkeypatch):
+    """Budget slack (budget above the measured value) must be disclosed.
+
+    The guard only fails on overflow (measured > budget), so a merge that
+    reverts a tightened budget passes silently unless the report line shows
+    the reopened headroom.  See the same_runtime_forks hunk straddle when
+    merging two budget-tightening branches.
+    """
+    import copy
+
+    smoke = runpy.run_path(str(SMOKE))
+    registry = smoke["load_registry"]()
+    sources = smoke["load_sources"](REPO_ROOT)
+    # Pinned budgets disclose no slack for the counters this change locks
+    # (the multi_value_twins slack belongs to the multi-value single-source
+    # batch, not this one).
+    _, pinned = smoke["check_inventory"](registry, sources)
+    assert "slack=conflicting_values" not in pinned, pinned
+    assert "slack=conflicting_definitions" not in pinned, pinned
+    # A two-file budget revert (the merge-trap shape: registry and anchor
+    # move back together, so the equality anchor stays satisfied) must show
+    # up as disclosed slack instead of passing silently.
+    widened = copy.deepcopy(registry)
+    widened["inventory_ratchets"]["conflicting_values"] += 2
+    monkeypatch.setitem(
+        smoke["BUDGET_ANCHOR"], "conflicting_values", widened["inventory_ratchets"]["conflicting_values"],
+    )
+    _, line = smoke["check_inventory"](widened, sources)
+    assert "slack=conflicting_values=2" in line, line