feat(quality): store real section titles for .tex chunks (R-F)

Add quality.section_label(title, content): for section-aware .tex ingest, keep the controlled bucket (intro/theorem/proof/abstract/bibliography) when the real \section heading maps to one, else store the cleaned title verbatim (e.g. 'preliminaries', 'rigidity') instead of collapsing to 'body'. Math papers title most sections descriptively, so R-C's vocab-only mapping left ~90% as 'body'; this lifts the section signal toward near-full. .pdf/.txt/run_quality_pass keep content-based classify_section unchanged. Safe because the section column is write-only (no consumer filters on the vocab).

New _clean_title (strip LaTeX/numbering, lower-case, truncate). Tests: section_label bucket/verbatim/fallback paths + _clean_title; .tex ingest stores a descriptive heading as its title. Full suite 377 passed; ruff + mypy clean.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

codex/ingest.py

@@ -12,7 +12,7 @@ from codex.config import get_settings
 from codex.db import get_conn
 from codex.embed import get_embedder
 from codex.models import Citation, Paper
-from codex.quality import classify_section, is_quality_chunk
+from codex.quality import is_quality_chunk, section_label
 from codex.sources import arxiv, crossref, openalex, semanticscholar
 
 logger = logging.getLogger(__name__)
@@ -312,10 +312,11 @@ def ingest_paper(
                         ord_idx,
                         content,
                         chunk_embeddings[ord_idx].tolist(),
-                        # .tex: classify from the section heading (prepended to the
-                        # snippet) so the label reflects the real section; otherwise
-                        # fall back to content-only classification.
-                        classify_section(f"{title}. {content}" if title else content),
+                        # .tex: label from the real \section heading — keeps the
+                        # controlled bucket when it matches, else stores the cleaned
+                        # title (R-F); .txt/.pdf (title=None) classify by content.
+                        # NB: `section` semantics now differ by source (write-only col).
+                        section_label(title, content),
                     )
                     for ord_idx, (title, content) in enumerate(kept_pairs)
                 ]

codex/quality.py

@@ -110,6 +110,42 @@ def classify_section(text: str) -> str:
     return "body"
 
 
+def _clean_title(title: str) -> str:
+    """Normalize a LaTeX ``\\section`` title for use as a section label.
+
+    Strips LaTeX commands (``\\emph`` …) and ``{}$``, drops leading section
+    numbering (``3.2 ``), collapses whitespace, lower-cases, and truncates to
+    60 chars so the stored ``section`` value is a clean, comparable string.
+    """
+    t = re.sub(r"\\[a-zA-Z]+\*?", " ", title)  # LaTeX commands
+    t = re.sub(r"[{}$]", "", t)  # braces / math delimiters
+    t = re.sub(r"^\s*\d+(?:\.\d+)*\.?\s*", "", t)  # leading numbering "3.2 "
+    return " ".join(t.split()).strip().lower()[:60]
+
+
+def section_label(title: str | None, content: str) -> str:
+    """Label a chunk's section, preferring the real ``\\section`` heading (R-F).
+
+    For section-aware ``.tex`` ingest *title* is the real heading: if it maps to a
+    controlled bucket via :func:`classify_section` (intro / theorem / proof /
+    abstract / bibliography) that bucket is kept (cross-source consistency);
+    otherwise the cleaned title itself is stored (e.g. ``"preliminaries"``,
+    ``"rigidity"``) — far more signal than collapsing everything to ``body``.
+
+    When *title* is None / blank (the ``.pdf`` / ``.txt`` / ``run_quality_pass``
+    paths) this falls back to content-based :func:`classify_section` — unchanged
+    behaviour. Safe to store free-text titles because the ``section`` column is
+    write-only (no consumer filters on the controlled vocabulary).
+    """
+    if not title or not title.strip():
+        return classify_section(content)
+    cleaned = _clean_title(title)
+    if not cleaned:
+        return classify_section(content)
+    bucket = classify_section(cleaned)
+    return bucket if bucket != "body" else cleaned
+
+
 # ---------------------------------------------------------------------------
 # Batch filter
 # ---------------------------------------------------------------------------

tests/ingest/test_ingest.py

@@ -128,6 +128,7 @@ def test_ingest_paper_source_tex(tmp_path: Any) -> None:
     section_pairs = [
         ("Introduction", "Body of the introduction goes here."),
         ("Proof of the Main Theorem", "Body of the proof goes here."),
+        ("3.2 Discrete Conformal Maps", "Body about discrete conformal maps."),
     ]
 
     with (
@@ -151,9 +152,11 @@ def test_ingest_paper_source_tex(tmp_path: Any) -> None:
     chunk_sql: str = chunk_insert_call[0][0]
     assert "INSERT INTO chunks" in chunk_sql
 
-    # Section label comes from the heading: "Introduction" → intro, "Proof of…" → proof.
+    # R-F: heading → controlled bucket where it maps ("Introduction"→intro,
+    # "Proof of…"→proof), else the cleaned real title ("discrete conformal maps")
+    # instead of collapsing to "body".
     chunk_rows = chunk_insert_call[0][1]
-    assert [row[4] for row in chunk_rows] == ["intro", "proof"]
+    assert [row[4] for row in chunk_rows] == ["intro", "proof", "discrete conformal maps"]
     assert result.chunks_upserted == len(section_pairs)
 
 

tests/quality/test_quality.py

@@ -6,10 +6,12 @@ from unittest.mock import MagicMock
 
 from codex.quality import (
     _bib_score,
+    _clean_title,
     classify_section,
     filter_chunks,
     is_quality_chunk,
     run_quality_pass,
+    section_label,
 )
 
 # ---------------------------------------------------------------------------
@@ -243,3 +245,36 @@ class TestRunQualityPass:
         kwargs = update_calls[0][0][1]
         assert kwargs["section"] == "abstract"
         assert kwargs["id"] == 5
+
+
+class TestCleanTitle:
+    def test_strips_leading_numbering(self):
+        assert _clean_title("3.2 Variational Principles") == "variational principles"
+
+    def test_strips_latex_and_braces(self):
+        assert _clean_title(r"The \emph{Discrete} Laplacian") == "the discrete laplacian"
+
+    def test_collapses_and_lowercases(self):
+        assert _clean_title("  Rigidity   Results  ") == "rigidity results"
+
+
+class TestSectionLabel:
+    def test_title_maps_to_controlled_bucket(self):
+        # Headings matching the controlled vocab keep the canonical bucket.
+        assert section_label("Introduction", "body text") == "intro"
+        assert section_label("Proof of Theorem 3", "body text") == "proof"
+        assert section_label("References", "body text") == "bibliography"
+
+    def test_descriptive_title_stored_verbatim(self):
+        # R-F win: a non-vocab heading is stored as its cleaned title, not "body".
+        assert section_label("Preliminaries", "body text") == "preliminaries"
+        assert section_label("3.1 Discrete Conformal Maps", "x") == "discrete conformal maps"
+
+    def test_none_or_blank_title_falls_back_to_content(self):
+        # .pdf/.txt path: unchanged content-based classification.
+        assert section_label(None, "Theorem 1. Let X be ...") == "theorem"
+        assert section_label("", "ordinary body prose here") == "body"
+
+    def test_title_cleaning_to_empty_falls_back_to_content(self):
+        # A pure-numbering heading cleans to "" → classify by content instead.
+        assert section_label("3.2", "Lemma 2. Suppose ...") == "theorem"