fix: gate weak boundary signals through backmatter_boundary_candidate

paperforge/worker/ocr_blocks.py

@@ -9,7 +9,6 @@ from paperforge.worker.ocr_roles import assign_block_role
 _CANDIDATE_ROLES = frozenset({
     "figure_caption_candidate",
     "backmatter_heading_candidate",
-    "backmatter_boundary_candidate",
 })
 
 

paperforge/worker/ocr_document.py

@@ -1704,27 +1704,7 @@ def _resolve_ambiguous_candidates(
 
             block["role"] = "backmatter_heading"
 
-        # ---- 2.2 Resolve backmatter_boundary_candidate ----
-        if role == "backmatter_boundary_candidate":
-            is_in_tail = (body_end_page is not None and page >= body_end_page) or (
-                doc_structure.spread_start is not None and page >= doc_structure.spread_start
-            )
-            if not is_in_tail:
-                block["role"] = "section_heading"
-                continue
-
-            layout = page_layouts.get(page)
-            boundaries = layout.column_boundaries if layout else []
-            x_center = (bbox[0] + bbox[2]) / 2
-            col = _get_column_index_by_boundaries(x_center, boundaries)
-
-            child_count = _child_heading_count(i, page, col, boundaries)
-            if child_count >= 2.0:
-                block["role"] = "backmatter_boundary_heading"
-            else:
-                block["role"] = "section_heading"
-
-        # ---- 2.3 Resolve figure_caption_candidate ----
+        # ---- 2.2 Resolve figure_caption_candidate ----
         if role == "figure_caption_candidate":
             text = block.get("text", "") or ""
             page_blocks = [b for b in blocks if b.get("page") == page]

paperforge/worker/ocr_roles.py

@@ -459,10 +459,28 @@ def assign_block_role(
         _page_num = block.get("page", 1) or 1
         _total_pages = max((b.get("page", 1) or 1) for b in page_blocks) if page_blocks else _page_num
         if _is_backmatter_boundary_heading(block, _page_num, _total_pages):
+            role_name = "backmatter_boundary_heading"
+            confidence = 0.7
+            lower_txt = text.lower()
+            has_container_words = any(
+                w in lower_txt
+                for w in ["additional information", "declaration", "supplementary"]
+            )
+            span_meta = block.get("span_metadata", {}) or {}
+            is_bold = False
+            if isinstance(span_meta, dict):
+                is_bold = "bold" in (span_meta.get("flags", "") or "").lower()
+            elif isinstance(span_meta, list):
+                is_bold = any(s.get("flags", 0) & 16 for s in span_meta)
+            if not (has_container_words and is_bold):
+                role_name = "backmatter_boundary_candidate"
+                confidence = 0.5
             return RoleAssignment(
-                role="backmatter_boundary_heading",
-                confidence=0.7,
-                evidence=[f"backmatter boundary heading: {text[:60]}"],
+                role=role_name,
+                confidence=confidence,
+                evidence=[
+                    f"backmatter {'boundary heading' if role_name == 'backmatter_boundary_heading' else 'boundary candidate'}: {text[:60]}"
+                ],
             )
         if _has_heading_numbering(text):
             depth = _heading_number_depth(text)
@@ -732,10 +750,28 @@ def assign_block_role(
         _pn2 = block.get("page", 1) or 1
         _tp2 = max((b.get("page", 1) or 1) for b in page_blocks) if page_blocks else _pn2
         if _is_backmatter_boundary_heading(block, _pn2, _tp2):
+            role_name = "backmatter_boundary_heading"
+            confidence = 0.7
+            lower_txt = text.lower()
+            has_container_words = any(
+                w in lower_txt
+                for w in ["additional information", "declaration", "supplementary"]
+            )
+            span_meta = block.get("span_metadata", {}) or {}
+            is_bold = False
+            if isinstance(span_meta, dict):
+                is_bold = "bold" in (span_meta.get("flags", "") or "").lower()
+            elif isinstance(span_meta, list):
+                is_bold = any(s.get("flags", 0) & 16 for s in span_meta)
+            if not (has_container_words and is_bold):
+                role_name = "backmatter_boundary_candidate"
+                confidence = 0.5
             return RoleAssignment(
-                role="backmatter_boundary_heading",
-                confidence=0.7,
-                evidence=[f"backmatter boundary heading from text block: {text[:60]}"],
+                role=role_name,
+                confidence=confidence,
+                evidence=[
+                    f"backmatter {'boundary heading' if role_name == 'backmatter_boundary_heading' else 'boundary candidate'} from text block: {text[:60]}"
+                ],
             )
 
         if len(text) < 20:

tests/test_ocr_roles.py

@@ -463,6 +463,33 @@ def test_formal_figure_caption_still_direct() -> None:
     )
 
 
+def test_weak_backmatter_boundary_signal_emits_candidate():
+    """A paragraph with backmatter boundary text but no bold span_metadata
+    should emit backmatter_boundary_candidate, not backmatter_boundary_heading."""
+    from paperforge.worker.ocr_roles import assign_block_role
+    block = {
+        "block_label": "paragraph_title",
+        "block_content": "ADDITIONAL INFORMATION",
+        "block_bbox": [100, 1200, 500, 1240],
+        "page": 8,
+    }
+    page_blocks = [block] + [
+        {
+            "block_label": "text",
+            "block_content": f"Some body text {i}",
+            "block_bbox": [100, 200 + i * 100, 500, 260 + i * 100],
+            "page": 8,
+        }
+        for i in range(5)
+    ]
+    result = assign_block_role(
+        block, page_blocks=page_blocks, page_width=600, page_height=1600
+    )
+    assert result.role == "backmatter_boundary_candidate", (
+        f"Expected backmatter_boundary_candidate, got {result.role}"
+    )
+
+
 def test_backmatter_boundary_detects_on_early_page() -> None:
     """Backmatter boundary should be detectable on papers with fewer
     than 8 pages, without a hard page gate."""