phase: 140_pictorial_pdf_pages

Everything is verified green. Final report:

## Phase 140 final verification pass — report

- Verified all 4 tasks already complete (code in working tree, task files in `complete/`): `pictorial_pages` gate + 2 settings (`BOR_PDF_PICTORIAL`, `BOR_PDF_PICTORIAL_MIN_CHARS` + validator), `PICTORIAL_PAGE_MODE`/`describe_pdf_page` seam + `render_pdf_pages` page selector + mock branch, `_pictorial_pdf_pass` in `_index_pdf_file` with log-only counters, dedicated E2E. No code changes needed.
- Test results (exact commands):
  - `uv run pytest --cov=app --cov-report=term-missing` → **3320 passed, 11 skipped, 0 failed; TOTAL 99%** (>90% gate)
  - `uv run pytest tests/e2e/test_pictorial_pdf.py -v --no-cov` → **3 passed in isolation** (Playwright, mock-only)
  - Pre-existing suites unedited: `test_pdf_support.py` 6 passed; `test_garbage_pdf.py` 2 passed + 1 skipped (owner fixture); `test_pdf_image_context.py` 4 passed
  - `uv run ruff check .` → All checks passed; `uv run pyright` → 0 errors
- Completion criteria:
  1. IKEA tar import repro — pinned by 2 integration tests; **skipped loudly here** (`test_sources/ikea_instructions.tar` absent on this machine — verified repo-wide; same house convention as completed phase-133 HNB tests; runs real on the owner's machine). Equivalent logic fully covered by unit pins on synthetic IKEA-class (vector-drawn, zero-raster) PDFs.
  2. Chat grounded on described page — **green** (E2E test b: phrase-only-in-illustration question, PDF in `done.sources`, answer echoes the block)
  3. Clean-text no-op (zero vision calls) + garbage precedence pin — **green** (`test_zero_candidates_is_a_noop` unit; `test_garbage_pdf_with_pictorial_on_takes_the_fallback_not_the_pass` integration, verified alone)
  4. `BOR_PDF_PICTORIAL=0` byte-identical — **green** (unit pin on synthetic PDF; IKEA variant runs on owner's machine)
  5. Full gate + E2E isolation + pre-existing suites — **green** (above)
  6. ruff + pyright — **clean**
  7. Commit/phase-move — delegated to harness per run rules (left in working tree: 16 modified + 8 new files, uncommitted)
- Deviations: none beyond the expected owner-fixture skips (11, all pre-existing fixture-missing skips, including 2 IKEA).
- Next pending phase: **none** — `todo/` holds only 140; 139 is already complete.

app/rag/importer.py

@@ -129,6 +129,28 @@ as unchanged (no re-chunk/re-embed/re-summary, no KB change; the
 vision calls are re-issued each sync — the no-cache cost, documented
 in :func:`_fallback_page_screenshots`).
 
+Pictorial sparse pages (phase 140, task 03, LOCKED A1–A4): AFTER the
+phase-133 gate, a PDF whose text layer is USABLE gets the sparse-page
+pass (:func:`_pictorial_pdf_pass`, gated by the ``pdf_pictorial``
+setting — ``BOR_PDF_PICTORIAL``, the house kill-switch): the
+deterministic gate (:func:`app.rag.pdf.pictorial_pages` — NO LLM
+call, LOCKED A1) selects the pages whose stripped text is under
+``pdf_pictorial_min_chars``; EVERY candidate is rendered (PLAN A21 —
+no page cap, no call budget) and vision-described through the phase-
+140 seam (:func:`app.rag.summarizer.describe_pdf_page` — the
+``PICTORIAL_PAGE_MODE`` one-shot, fail-soft per page), and the
+description appends to the page's content block as
+``[Page N illustration: …]`` (LOCKED A2 — no LLM judge: every
+described page joins the content; the owner's L5 rationale: more
+information is better for the embeddings). The precedence is locked:
+the pass runs on a USABLE layer ONLY — an unusable layer takes the
+phase-133 full-page screenshot fallback and never burns a second
+vision pass. Zero candidates → a no-op (no render, no vision call —
+a clean-text PDF's path is byte-identical to pre-phase); the
+counters ``pdfs_pictorial`` / ``pdf_pictorial_pages`` are log-only
+(the sync ``detail`` API shape is untouched, the stats log-only
+convention).
+
 Image-anchor context (phase 125, task 03, LOCKED A1/A2/A3): BEFORE the
 description, the same source's importable markdown files are scanned for
 ``![alt](path)`` references that name the image (the task-02
@@ -250,6 +272,7 @@ from app.rag.pdf import (
     extract_pdf_page_texts,
     extract_pdf_text,
     is_usable_pdf_text,
+    pictorial_pages,
     render_pdf_pages,
 )
 from app.rag.retriever import TRUNCATION_MARKER
@@ -257,6 +280,7 @@ from app.rag.summarizer import (
     IMAGE_FALLBACK_MIME,
     IMAGE_MIMES,
     describe_image,
+    describe_pdf_page,
     generate_summary,
 )
 
@@ -341,6 +365,20 @@ class ImportSummary:
     #: ``---PAGE-N---``-anchored descriptions, or ``""`` when the
     #: fallback produced nothing — the phase-126 empty-content path).
     pdfs_screenshotted: int = 0
+    #: PDFs (phase 140, task 03, LOCKED A2/A4) whose USABLE text layer
+    #: carried ≥1 pictorial candidate page (``app.rag.pdf.
+    #: pictorial_pages`` — the deterministic sparse-page gate, LOCKED
+    #: A1) whose vision description was appended to the page block
+    #: (``[Page N illustration: …]``) — the sparse-page pass
+    #: (:func:`_pictorial_pdf_pass`). Log-only (the sync ``detail``
+    #: API shape is untouched — the stats log-only convention,
+    #: phase 133); ``pdf_pictorial_pages`` counts the described pages.
+    pdfs_pictorial: int = 0
+    #: Pictorial candidate pages described across the run (phase 140,
+    #: task 03) — one PDF with three described sparse pages counts
+    #: ``pdfs_pictorial=1`` + ``pdf_pictorial_pages=3`` (A21: no page
+    #: cap — the count may be large, that is the point).
+    pdf_pictorial_pages: int = 0
     #: PDF-embedded image docs whose stored ``image_context`` was
     #: backfilled with the document-context block (phase 137, task 03)
     #: — the one-time best-effort pass; a success never repeats, a
@@ -367,7 +405,8 @@ class ImportSummary:
             "import: summary files=%d added=%d updated=%d unchanged=%d pruned=%d "
             "errors=%d chunks=%d embed_batches=%d summaries=%d summary_errors=%d "
             "summary_backfilled=%d dates_updated=%d images_failed=%d "
-            "image_context_backfilled=%d pdfs_screenshotted=%d formats=%s",
+            "image_context_backfilled=%d pdfs_screenshotted=%d "
+            "pdfs_pictorial=%d pdf_pictorial_pages=%d formats=%s",
             self.files,
             self.added,
             self.updated,
@@ -383,6 +422,8 @@ class ImportSummary:
             self.images_failed,
             self.image_context_backfilled,
             self.pdfs_screenshotted,
+            self.pdfs_pictorial,
+            self.pdf_pictorial_pages,
             self.format_counts(),
         )
 
@@ -1165,6 +1206,19 @@ async def _index_pdf_file(
       An unopenable PDF — or one whose fallback also produced nothing
       — yields ``""`` (still a document — it may carry embedded images
       — with no content chunks; a warning is the signal).
+    * Phase 140 (task 03, LOCKED A1–A4): when the layer is USABLE and
+      ``settings.pdf_pictorial`` is on, the sparse-page pass
+      (:func:`_pictorial_pdf_pass`) renders + vision-describes every
+      page whose stripped text is under
+      ``settings.pdf_pictorial_min_chars`` (the deterministic gate —
+      NO LLM call, A1; every candidate, no page cap — A21/A3) and
+      appends the description to the page block as
+      ``[Page N illustration: …]`` (A2/A4). The precedence is locked:
+      the pass sits AFTER the phase-133 gate, so an unusable layer
+      (the fallback's full-page screenshots) never burns a second
+      vision pass; zero candidates → a no-op (the extracted text
+      stays byte-identical to the pre-phase-140 path — no render, no
+      vision call).
     * the sha256 digest is over the FINAL content (the digest rule is
       content identity — the same text is the same document version;
       the fallback's constructed page descriptions digest exactly the
@@ -1213,6 +1267,20 @@ async def _index_pdf_file(
         content = await _fallback_page_screenshots(
             session, source=source, rel=rel, full_path=full_path, llm=llm
         )
+    elif llm.settings.pdf_pictorial:
+        # Phase 140 (task 03, LOCKED A1–A4): the pictorial pass —
+        # USABLE layers only (the precedence is locked: the phase-133
+        # fallback above already screenshotted an unusable layer, no
+        # double vision). Zero candidates → a no-op (the pass returns
+        # None — the extracted text stays byte-identical to the
+        # pre-phase-140 path); otherwise the FINAL content carries the
+        # described candidates' illustration blocks (A4: the digest
+        # below runs over it, the phase-126/133 convention).
+        passed = await _pictorial_pdf_pass(
+            source=source, rel=rel, full_path=full_path, llm=llm, summary=summary
+        )
+        if passed is not None:
+            content = passed
     if not content:
         logger.warning(
             "import: PDF has no extractable text source=%s path=%s", source, rel
@@ -1406,6 +1474,128 @@ async def _fallback_page_screenshots(
     )
 
 
+async def _pictorial_pdf_pass(
+    *,
+    source: str,
+    rel: str,
+    full_path: Path,
+    llm: Embedder,
+    summary: ImportSummary,
+) -> str | None:
+    """The phase-140 (task 03) pictorial pass (LOCKED A1–A4) — the
+    IKEA assembly-instruction class (TODO L5): a PDF whose text layer
+    is USABLE but SPARSE (mostly pictorial pages — 4–73 chars of
+    markers around vector-drawn pictograms) gets every sparse page
+    rendered to a PNG and vision-described, and the description
+    APPENDS to that page's indexed content block
+    (``[Page N illustration: …]``) — the page's text stays, so the
+    embeddings carry what the thin text layer couldn't (the owner's
+    L5 rationale: "More information is better when generating the
+    text embeddings").
+
+    * the gate is :func:`app.rag.pdf.pictorial_pages` over
+      :func:`app.rag.pdf.extract_pdf_page_texts` — deterministic, NO
+      LLM call (LOCKED A1): the 1-based page numbers whose stripped
+      text is under ``settings.pdf_pictorial_min_chars``, ascending.
+      (The kill-switch itself — ``settings.pdf_pictorial`` — gates the
+      whole pass in the caller: while off, this function is never
+      called and the content is byte-identical to pre-phase.)
+    * ZERO candidates → a NO-OP (returns ``None``): no render, no
+      vision call — the caller keeps its :func:`extract_pdf_text`
+      output untouched, so a clean-text PDF's path is byte-identical
+      to the pre-phase-140 path (the pin).
+    * a page that could not be rendered (the zero-byte
+      :func:`render_pdf_pages` placeholder — the index never shifts,
+      so it stays aligned with the candidates) is skipped with a
+      warning (the phase-133 handling — the page keeps its text only,
+      no vision call is burned for it); a page whose vision call
+      failed or came back blank (:func:`describe_pdf_page` →
+      ``None``) is skipped with a warning and keeps its text only —
+      one dead page never kills the pass (LOCKED A2 fail-soft).
+    * the assembly (LOCKED A4): every page of the
+      :func:`extract_pdf_page_texts` map (the SAME pages, order and
+      stripped text as :func:`extract_pdf_text`) as its
+      :data:`PAGE_SEPARATOR` + the page text + — for the described
+      candidates — ``"\\n\\n[Page {n} illustration: {description}]"``.
+      The assembly with NO descriptions is byte-identical to
+      :func:`extract_pdf_text`'s output (the unit pin).
+    * the caller's digest runs over this FINAL content (the
+      phase-126/133 convention — A4): a stable file + a stable vision
+      reply re-syncs as ``unchanged``; a non-deterministic re-describe
+      re-updates the row — a cost, not a bug (the phase-133 docstring
+      documents it, A21 endorses it).
+    * stats (log-only — the sync ``detail`` API shape is untouched,
+      the phase-133 convention): ``summary.pdfs_pictorial`` (+1 when
+      ≥1 page was described) and ``summary.pdf_pictorial_pages``
+      (+the described page count), plus the ONE loud log line (PLAN
+      §9): ``pdf: pictorial pass source=… path=… — N candidate pages,
+      M described (min_chars=…)``.
+    """
+    settings = llm.settings
+    page_texts = extract_pdf_page_texts(full_path)
+    candidates = pictorial_pages(
+        page_texts, min_chars=settings.pdf_pictorial_min_chars
+    )
+    if not candidates:
+        return None
+    # ONE render for the whole candidate set (the phase-140 selector —
+    # a 500-page PDF with 30 sparse pages renders 30 PNGs, not 500);
+    # the result is aligned with *candidates* (ascending, one slot
+    # each — a zero-byte placeholder never shifts the positions).
+    pngs = render_pdf_pages(full_path, pages=candidates)
+    descriptions: dict[int, str] = {}
+    # strict: the render's result is aligned with the candidate list by
+    # contract (one slot per named page, ascending) — a length drift is
+    # a parser regression, fail loud.
+    for page, png in zip(candidates, pngs, strict=True):
+        if not png:
+            # The phase-133 zero-byte placeholder: an unreadable page.
+            logger.warning(
+                "pdf: skipping pictorial page %d of %s/%s — the render is "
+                "empty (unreadable page)",
+                page, source, rel,
+            )
+            continue
+        desc = await describe_pdf_page(
+            llm,
+            data=png,
+            mime="image/png",
+            page=page,
+            page_text=page_texts[page],
+        )
+        if desc is None:
+            # Fail-soft (LOCKED A2): one dead page never kills the
+            # pass — the page keeps its text only, the sync continues.
+            logger.warning(
+                "pdf: pictorial page %d of %s/%s has no description — "
+                "the page keeps its text only",
+                page, source, rel,
+            )
+            continue
+        descriptions[page] = desc
+    # The ONE loud log line (PLAN §9): N candidate pages, M described.
+    logger.info(
+        "pdf: pictorial pass source=%s path=%s — %d candidate pages, %d "
+        "described (min_chars=%d)",
+        source, rel, len(candidates), len(descriptions),
+        settings.pdf_pictorial_min_chars,
+    )
+    # The stats (log-only — the sync ``detail`` API shape is untouched).
+    if descriptions:
+        summary.pdfs_pictorial += 1
+    summary.pdf_pictorial_pages += len(descriptions)
+    # The assembly: the extracted text's page blocks, the described
+    # candidates carrying their illustration block (A4 — the page's
+    # text STAYS; the description appends after it).
+    parts: list[str] = []
+    for page, text in page_texts.items():
+        block = text
+        if page in descriptions:
+            block += f"\n\n[Page {page} illustration: {descriptions[page]}]"
+        parts.append(f"{PAGE_SEPARATOR.format(page=page)}\n{block}")
+    return "\n\n".join(parts)
+
+
 async def _index_pdf_embedded_images(
     session: Session,
     *,

app/rag/pdf.py

@@ -29,11 +29,20 @@ package, imported as ``fitz`` — its stable API name).
   I/O) — REAL content vs. garbage (the pre-126 XML/binary soup, the
   empty text layer). It is the single trigger for the page-screenshot
   vision fallback (phase 133 task 03).
+* :func:`pictorial_pages` — the phase-140 sparse-page gate: the 1-based
+  page numbers of a :func:`extract_pdf_page_texts` map whose stripped
+  text is STRICTLY under *min_chars* chars (ascending) — pure,
+  deterministic, NO LLM call (LOCKED A1): the "way to determine when
+  that's necessary" (TODO L5) for the pictorial pass.
 * :func:`render_pdf_pages` — the fallback's visual input (phase 133
-  task 03): one PNG per page (150 DPI, page order); an unreadable page
-  yields ``b""`` (the caller's placeholder — the page index never
-  shifts), an unopenable file yields ``[]`` (the caller's existing
-  empty-content path).
+  task 03): one PNG per page (150 DPI, page order); the phase-140
+  optional 1-based *pages* selector renders ONLY the named pages
+  (ascending — a 500-page PDF with 30 sparse pages renders 30 PNGs,
+  not 500), ``None`` = every page (the phase-133 caller's result is
+  byte-identical); an unreadable (or out-of-range named) page yields
+  ``b""`` at its position (the caller's placeholder — the result
+  stays aligned with the requested pages), an unopenable file yields
+  ``[]`` (the caller's existing empty-content path).
 
 Every failure mode is fail-soft: an unreadable file returns an empty
 result, an unreadable page or image is logged and skipped — this module
@@ -43,7 +52,7 @@ from __future__ import annotations
 
 import logging
 import re
-from collections.abc import Iterator
+from collections.abc import Iterator, Sequence
 from dataclasses import dataclass
 from pathlib import Path
 from typing import Any
@@ -264,15 +273,60 @@ def is_usable_pdf_text(text: str) -> bool:
     return non_printable / len(text) < NONPRINT_CHAR_FRACTION
 
 
-def render_pdf_pages(pdf_path: Path, dpi: int = 150) -> list[bytes]:
-    """Render every page of *pdf_path* to a PNG (page order — list index
-    *i* is page *i*+1).
+def pictorial_pages(page_texts: dict[int, str], *, min_chars: int) -> list[int]:
+    """The 1-based page numbers of *page_texts* that are PICTORIAL
+    candidates: ``len(text.strip()) < min_chars`` — STRICTLY less than
+    (a page with exactly *min_chars* stripped chars is NOT sparse; the
+    boundary is pinned in the unit tests), ascending.
+
+    The deterministic sparse-page gate (phase 140, task 01, LOCKED A1)
+    — the "way to determine when that's necessary" for the pictorial PDF
+    pass (TODO L5): NO LLM call, pure, deterministic (no PDF, no I/O —
+    the input is a :func:`extract_pdf_page_texts` map, so the gate never
+    re-opens the file). A page that carries no text at all has NO key in
+    the map and is therefore not a candidate here (the importer's pass
+    owns the page-total handling); an empty map yields ``[]`` — a
+    clean-text PDF's path never burns a vision call.
+
+    The IKEA example (the phase-140 fixture, ``min_chars=100``):
+    ``{1: "BESTÅ", 2: <7 KB of warnings>, 6: "Illustration 6"}`` →
+    ``[1, 6, …]`` — page 1 (the title page: the logo + product name) IS
+    a candidate: describing it is useful (the logo + product name) and
+    never harmful; page 2's 7 KB of multilingual warnings is not.
+
+    ``min_chars=0`` is the documented PLAN A21 special case — **every
+    page in the map is a candidate** (the "describe everything" mode).
+    The strict-``<`` test cannot express this (no length is below 0), so
+    0 is not "a stricter bar": it is the A21 no-cap endpoint, and a
+    negative value — unreachable through ``Settings`` (the validator
+    fails startup loudly) — takes the same branch defensively.
+    """
+    if min_chars <= 0:
+        return sorted(page_texts)
+    return sorted(
+        page for page, text in page_texts.items() if len(text.strip()) < min_chars
+    )
+
+
+def render_pdf_pages(
+    pdf_path: Path, dpi: int = 150, pages: Sequence[int] | None = None
+) -> list[bytes]:
+    """Render the selected pages of *pdf_path* to PNGs.
+
+    *pages* (phase 140, task 02): the optional 1-based selector —
+    render ONLY the named pages, in ascending order, one PNG each
+    (a 500-page PDF with 30 pictorial candidates renders 30 PNGs, not
+    500). ``None`` (the default) = every page in page order — the
+    phase-133 caller's result is byte-identical, so list index *i* is
+    page *i*+1 (with a selector, list index *i* is the *i*-th smallest
+    NAMED page).
 
     The fallback's visual input (phase 133 task 03, ASSUMPTION A8:
     fixed 150 DPI — the balance of vision legibility vs data-URL
-    payload). A page that cannot be rendered yields ``b""`` (the
-    caller's placeholder — the page index NEVER shifts, so
-    ``---PAGE-N---`` stays truthful; the failure is logged, the
+    payload). A page that cannot be rendered — including a named page
+    outside the document's page range — yields ``b""`` at ITS position
+    (the caller's placeholder — the result's order NEVER shifts, so it
+    stays aligned with the requested pages; the failure is logged, the
     :func:`extract_pdf_text` fail-soft style). A file that cannot be
     OPENED yields ``[]`` (the caller's existing empty-content path —
     the doc lands with the no-extractable-text behavior, unchanged).
@@ -283,18 +337,29 @@ def render_pdf_pages(pdf_path: Path, dpi: int = 150) -> list[bytes]:
         logger.warning("pdf: could not open %s for page rendering — %s", pdf_path, exc)
         return []
 
-    pages: list[bytes] = []
+    # 1-based page numbers: the default walks every page in page order
+    # (the phase-133 contract — list index *i* is page *i*+1); a
+    # selector renders the named pages, ascending (de-duplicated — a
+    # repeated page number would render it twice for no reason).
+    numbers = (
+        range(1, len(doc) + 1)
+        if pages is None
+        else sorted(set(pages))
+    )
+    rendered: list[bytes] = []
     with doc:
-        for page_num in range(len(doc)):
+        for page_number in numbers:
             try:
-                pages.append(doc[page_num].get_pixmap(dpi=dpi).tobytes("png"))
+                rendered.append(
+                    doc[page_number - 1].get_pixmap(dpi=dpi).tobytes("png")
+                )
             except Exception as exc:
                 logger.warning(
                     "pdf: could not render page %d of %s — %s",
-                    page_num + 1, pdf_path, exc,
+                    page_number, pdf_path, exc,
                 )
-                pages.append(b"")
-    return pages
+                rendered.append(b"")
+    return rendered
 
 
 def extract_pdf_images(pdf_path: Path) -> list[PdfImage]:

app/rag/summarizer.py

@@ -33,10 +33,24 @@ it is not assumed vision-capable). Fail-soft by contract: any client
 error, empty reply, or non-2xx yields ``None`` — the importer skips
 the doc, counts ``images_failed``, and the sync continues.
 
-The ``SUMMARY_MODE`` / ``IMAGE_DESCRIPTION_MODE`` markers follow the
-``DEFLECT_MODE`` convention: the deterministic E2E mock LLM keys on
-them (``tests/e2e/mock_llm.py`` — the image branch is wired by task
-06's story suite).
+Pictorial PDF pages (phase 140, LOCKED A2): :func:`describe_pdf_page`
+is this module's third one-shot generation path — a SINGLE CHAT-model
+(vision) call describing ONE rendered sparse PDF page, with the
+page's OWN extracted text as context so the model describes what the
+text does NOT carry (the IKEA assembly-instruction class: vector
+pictograms around a 4–73-char text layer). The description is
+APPENDED to the page's indexed content block by the importer (the
+``[Page N illustration: …]`` line, LOCKED A4) — the page's text stays;
+more information is better for the embeddings (the owner's L5
+rationale). Fail-soft by contract: any client error or empty reply
+yields ``None`` — the importer skips that page with a warning and
+continues (one dead page never stalls a sync).
+
+The ``SUMMARY_MODE`` / ``IMAGE_DESCRIPTION_MODE`` /
+``PICTORIAL_PAGE_MODE`` markers follow the ``DEFLECT_MODE``
+convention: the deterministic E2E mock LLM keys on them
+(``tests/e2e/mock_llm.py`` — the image branch is wired by task
+06's story suite, the pictorial branch by phase 140 task 02).
 """
 from __future__ import annotations
 
@@ -92,8 +106,41 @@ DESCRIBE_INSTRUCTION = (
 
 #: The full describe prompt: marker first (the mock's key), then the
 #: instruction — the single text part of the multimodal user message.
+#: BYTE-IDENTICAL CONTRACT: the phase 122/126/137 suites pin this
+#: string untouched — pictorial-page descriptions go through their
+#: own marker (:data:`PICTORIAL_PAGE_MODE`), never a re-wrap of this
+#: one.
 DESCRIBE_PROMPT = f"{IMAGE_DESCRIPTION_MODE}: {DESCRIBE_INSTRUCTION}"
 
+#: Pictorial-page marker (phase 140, task 02, LOCKED A1/A2) — the
+#: deterministic E2E mock LLM keys on it (same convention as
+#: ``IMAGE_DESCRIPTION_MODE``, PLAN §6). It heads the text part of
+#: the multimodal describe message, so it rides the user message, not
+#: a system prompt.
+PICTORIAL_PAGE_MODE = "PICTORIAL_PAGE_MODE"
+
+#: Locked instruction for the CHAT (vision) model (phase 140, LOCKED
+#: A2): the description APPENDS to the page's indexed content block
+#: (``[Page N illustration: …]``) — the embeddings then carry what
+#: the thin text layer couldn't (the owner's L5 rationale) — so it
+#: must be a faithful, retrieval-oriented account of what the page
+#: SHOWS: the assembly steps, part names, arrows, tool icons, and
+#: before/after states — ESPECIALLY the information the extracted
+#: text does not contain.
+PICTORIAL_INSTRUCTION = (
+    "Describe in detail what this page of the PDF shows, in plain text, "
+    "for a search index. State the assembly steps, part names, arrows, "
+    "tool icons, and before/after states it illustrates — ESPECIALLY the "
+    "information the extracted text does not contain. Write 2-4 sentences "
+    "of substance. Do not use markdown. Do not invent anything that is "
+    "not visible on the page."
+)
+
+#: The full pictorial-page prompt: marker first (the mock's key), then
+#: the instruction — the head of the multimodal user message's text
+#: part (the page block is appended by :func:`describe_pdf_page`).
+PICTORIAL_PROMPT = f"{PICTORIAL_PAGE_MODE}: {PICTORIAL_INSTRUCTION}"
+
 #: Extension → MIME type for the image family (phase 122). Dotted,
 #: lowercase keys — the ``image_extension_set`` shape. Task 03 uses it
 #: for the describe call's data-URL mime; task 04's serve route reuses
@@ -266,11 +313,43 @@ async def describe_image(
         if context
         else ""
     )
+    return await _one_shot_vision_reply(
+        llm,
+        data_url=data_url,
+        text=DESCRIBE_PROMPT + context_prefix,
+        settings=settings,
+        what="image description",
+    )
+
+
+async def _one_shot_vision_reply(
+    llm: SummaryLLM,
+    *,
+    data_url: str,
+    text: str,
+    settings: Settings | None,
+    what: str,
+) -> str | None:
+    """The shared one-chat-call multimodal contract (phase 122, reused
+    by phase 140): ONE user message
+    ``[{type: "text", text: <text>},
+    {type: "image_url", image_url: {url: <data_url>}}]`` against
+    ``llm.settings.llm_chat_model`` — no system prompt, no tools, no
+    app-level retry.
+
+    Returns the stripped reply cut exactly at
+    ``(settings or llm.settings).summary_max_chars`` (the phase-30 cap);
+    ``None`` on any client error (the client raises :class:`LLMError`
+    for a failure, an empty reply, or a non-2xx) or an empty/blank
+    reply after trimming (the house one-shot empty-content policy — the
+    duck-typed fakes may return one even though the real client
+    rejects it). *what* names the caller for the warning log line.
+    """
     messages: list[dict[str, Any]] = [
         {
             "role": "user",
             "content": [
-                {"type": "text", "text": DESCRIBE_PROMPT + context_prefix},
+                {"type": "text", "text": text},
                 {"type": "image_url", "image_url": {"url": data_url}},
             ],
         }
@@ -279,12 +358,67 @@ async def describe_image(
     try:
         raw = await llm.chat(messages, model=model)
     except LLMError as e:
-        logger.warning("image description failed (model=%s): %s", model, e)
+        logger.warning("%s failed (model=%s): %s", what, model, e)
         return None
-    text = raw.strip()
-    if not text:
+    text_out = raw.strip()
+    if not text_out:
         # The client already rejects empty content; this is the
         # defensive re-assert (the duck-typed fakes may return it).
         return None
     limit = (settings or llm.settings).summary_max_chars
-    return text[:limit]
+    return text_out[:limit]
+
+
+async def describe_pdf_page(
+    llm: SummaryLLM,
+    *,
+    data: bytes,
+    mime: str,
+    page: int,
+    page_text: str | None,
+    settings: Settings | None = None,
+) -> str | None:
+    """One-shot CHAT-model (vision) description of ONE rendered PDF page
+    (phase 140, task 02, LOCKED A2) — the text the importer appends to
+    that page's indexed content block as
+    ``[Page N illustration: …]`` (the page's own text stays; the
+    embeddings then carry what the thin text layer couldn't — the
+    owner's L5 rationale).
+
+    ONE chat-model call against ``llm.settings.llm_chat_model`` (the
+    vision model — the ``lite`` summary model is NOT assumed
+    vision-capable) with the same multimodal contract as
+    :func:`describe_image` (via :func:`_one_shot_vision_reply`): no
+    system prompt, no tools, no app-level retry. The message's text
+    part is :data:`PICTORIAL_PROMPT` (the ``PICTORIAL_PAGE_MODE``
+    marker + the locked instruction) followed by the page block — the
+    page's OWN extracted text as context, so the model describes what
+    the text does NOT contain::
+
+        PICTORIAL_PROMPT
+        + "\\n\\nPage {page} of the PDF. Text extracted from this page:\n"
+        + (page_text.strip() or "(none)")
+
+    ``data`` is the rendered page's PNG bytes (phase 133's
+    ``render_pdf_pages`` output), ``mime`` its MIME type (``image/png``
+    for the rendered page).
+
+    Returns the stripped reply cut exactly at
+    ``(settings or llm.settings).summary_max_chars`` (the phase-30 cap).
+    Returns ``None`` on any client error, empty reply, or non-2xx
+    (fail-soft — the importer skips THAT page with a warning and
+    continues: one dead page never stalls a sync, LOCKED A2).
+    """
+    data_url = image_data_url(data, mime)
+    extracted = page_text.strip() if page_text is not None else ""
+    return await _one_shot_vision_reply(
+        llm,
+        data_url=data_url,
+        text=(
+            PICTORIAL_PROMPT
+            + f"\n\nPage {page} of the PDF. Text extracted from this page:\n"
+            + (extracted or "(none)")
+        ),
+        settings=settings,
+        what=f"pictorial page description (page={page})",
+    )