paper2assets

name	paper2assets
description	Extract a research paper PDF into a structured set of poster-agnostic assets reusable by any downstream renderer (paper2poster, paper2blog, paper2audio, paper2video). Produces a `<outdir>/` containing the paper's full text (assets/meta/text.txt), per-figure captions (assets/meta/captions.json), cleaned figure rasters (assets/figures/*.png + assets/meta/figures.json manifest), paper metadata (assets/meta/metadata.json: title / authors / institutes / venue / paper_url / code_url), institute logos (assets/logos/*), URL QR codes (assets/qr/*), and a 9-section structured paper summary (assets/meta/paper_spec.md). The bundle follows the Output Contract layout (deliverables at top, everything else under `assets/`). Use when the user wants to extract paper content into reusable assets, OR as the mandatory upstream stage of any paper-rendering pipeline — e.g., 'extract this paper', 'build paper assets', 'get the figures and spec from this PDF', 'paper2assets'.
allowed-tools	Bash(*), Read, Write, Edit, Grep, Glob, AskUserQuestion, WebFetch, WebSearch

paper2assets — paper PDF → reusable assets

One paper PDF in, a single <outdir>/ of poster-agnostic assets out, ready for any downstream renderer.

Output Contract (the shared layout every paper2* skill follows)

paper2assets defines the on-disk shape of every deliverable bundle in the pipeline. paper2poster, html2pptx, paper2blog, paper2video, and paper2reel all read from and write to a bundle laid out this way — a teammate adding or changing a downstream skill conforms to this contract.

Rules

1. The bundle directory is named after the paper.
2. The bundle's top level holds ONLY that skill's deliverable FILES — no loose intermediates, and as few folders as possible.
3. Every dependency and intermediate (figures, logos, qr, audio, fonts, captions, slides, the spec / json / txt) lives under one assets/ container.

Layout

<paper-name>/
|-- <deliverable files>          # see the per-skill table below
|-- manifest.json                # package index (root-relative paths); the one allowed top-level non-deliverable
`-- assets/
    |-- figures/  logos/  qr/  audio/  fonts/   # runtime deps the deliverables reference
    `-- meta/                                    # build intermediates
        |-- paper_spec.md  sections.json  narration.json
        `-- captions.json  figures.json  metadata.json  text.txt

Deliverables reference assets with root-relative src paths -- assets/figures/..., assets/logos/..., assets/qr/..., assets/audio/... -- so the bundle is self-contained and movable (no absolute paths leak in). The path / file fields in figures.json, fetch_logos.py, and make_qr.py output already carry the assets/ prefix; downstream drops them into src verbatim.

Per-skill deliverables (top-level FILES):

Skill	Top-level deliverable files
paper2assets	manifest.json (+ the whole assets/ package)
paper2poster	poster.html, poster.pdf, poster.png, poster.pptx
paper2blog	blog_zh.docx, blog_en.docx
paper2video	video.mp4, video_no_subtitles.mp4
paper2reel	reel.html

manifest.json's "files" map records every meta / figure path (root-relative) plus a "layout": "v2-assets" marker, so a consumer can locate inputs and tell a new bundle from a legacy flat one without re-walking the tree.

   paper.pdf  (+ arXiv id / provided image links)
     │
     ▼  FIGURES — priority: source_figures.py (arXiv source / provided links) → clean assets/figures/*.png + figures.json
     │           └─ fallback only: extract_pdf.py crops from the rendered PDF
     ▼  scripts/extract_pdf.py   → assets/meta/{text.txt, captions.json} (+ figures.json only on the crop fallback; use --no-figures on the source path)
     │
     ▼  Step 3 (model-driven)    → assets/meta/metadata.json
     │
     ▼  Step 4 (model-driven)    → assets/meta/paper_spec.md  (9 canonical sections)
     │
     ▼  scripts/crop_figure.py   → cleaned assets/figures/*.png  (CROP FALLBACK ONLY — skipped when source_figures.py supplied the originals)
     │
     ▼  scripts/fetch_logos.py   → assets/logos/<slug>.{png,svg}
     ▼  scripts/fetch_conf_logo.py → assets/logos/_venue.png  (conference mark; best-effort, skips on miss)
     │
     ▼  scripts/make_qr.py       → assets/qr/{paper,code}.png
     │
     ▼  scripts/build_package.py → assets/meta/{sections.json, narration.json} + manifest.json
     │
     └──→ <outdir>/ — every downstream renderer reads from here

Downstream renderers (paper2poster, paper2blog, paper2audio, ...) consume this outdir; none should re-derive any of these files.

Output contract

After paper2assets finishes, <outdir>/ MUST contain:

File	Source	Purpose
assets/meta/text.txt	Step 2	Full PDF text via pdftotext. Page breaks preserved as \f. Authoritative source of numbers/claims for any downstream prose.
assets/meta/captions.json	Step 2	[{page, label, text}, ...] per "Figure N: ..." caption detected in the PDF text.
assets/meta/figures.json	Step 2 + 5	[{file, width, height, page, layout}, ...] per extracted figure raster. layout is "full" / "col-0" / "col-1" etc. — the source-page column placement. width/height are updated whenever crop_figure.py runs.
assets/figures/<page>_figure<n>.png	Step 2 + 5	Cropped figure rasters @ zoom=6 (~432 dpi). Cleaned by Step 5's deterministic pipeline.
assets/figures/_debug/<page>_figure<n>.png.bak	Step 5	One-shot backup of the raw extract before Step 5's first crop. Preserved across re-runs (never clobbered). Lives under _debug/ so the top-level figures/ listing stays clean — downstream renderers should only ever read from figures/*.png.
assets/figures/_debug/<page>_figure<n>.marked-<NN>.png	Step 5d	Per-iteration overlay showing the bbox each mark call proposed (-01, -02, ...). Audit trail of the bbox-decision history. Never touched by downstream.
assets/meta/metadata.json	Step 3	{title, authors[], author_index_map{}, institutes[], venue, paper_url, code_url?}.
assets/meta/paper_spec.md	Step 4	9-section structured summary (Problem / Motivation / Contribution / Method / Dataset/Benchmark / Key Result / Ablation Study / Headline Numbers / Takeaway), each section with Necessary + Additional + Audio script subfields. Plus a YAML preamble with title/authors/institutes/venue and audio scripts.
assets/logos/<slug>.{png,svg}	Step 6	One logo per institute: Wikimedia Commons first, then a MANDATORY WebSearch/WebFetch fallback (--add-logo) for any institute the deterministic pass reports in its "missing" list — so logos should rarely be absent. Only genuinely unfindable institutes are dropped.
assets/qr/{paper,code}.png	Step 6	QR codes for the paper's links. make_qr.py classifies paper_url/project_url/code_url by destination (Paper/Code/Project), de-duplicates by URL, and writes up to two slots (slot 0 → paper.png, slot 1 → code.png) plus a qr manifest (path + label) into metadata.json. A one-link paper yields ONE QR (no code.png); the caption follows the URL, not the filename.
assets/meta/sections.json	Step 7	paper_spec.md parsed to per-section JSON (stable ids + necessary / additional / audio_script). Consumed by paper2blog / paper2video.
assets/meta/narration.json	Step 7	Audio script only — no mp3. TTS clip list {provider, voice, sections:[{id, heading, text}]} from the **Audio script:** markers (+ the title clip). Downstream renderers synthesize their own audio from this; paper2assets does NOT run TTS.
manifest.json	Step 7	Package inventory (file paths + counts + source-PDF sha256).

Workflow

Step 0 — Cache check (do this FIRST, before any other work)

Re-extracting a paper costs ~5-10 min of Claude tokens (figure-cleanup visual review + spec synthesis) and risks clobbering edits the user may have made to paper_spec.md, metadata.json, or cropped figures. Before starting, check whether the assets already exist under the default outdir convention (outdir = <input_pdf_dir>/<pdf_stem>/) or the caller-supplied outdir:

required=("$outdir/assets/meta/paper_spec.md" "$outdir/assets/meta/text.txt" \
          "$outdir/assets/meta/figures.json" "$outdir/assets/meta/metadata.json")
all_present=1
for f in "${required[@]}"; do [[ -f "$f" ]] || all_present=0; done
[[ -d "$outdir/assets/figures" && \
   $(ls "$outdir/assets/figures"/*.png 2>/dev/null | wc -l) -gt 0 ]] \
  || all_present=0

If all five artifacts are present, REPORT the cached state in 1-2 lines and STOP — do not re-extract:

[paper2assets] CACHED in <outdir> — assets from prior run, reusing.
  title: "<from metadata.json>"
  figures: N PNGs
  paper_spec.md: <line-count> lines, K sections

Re-extract ONLY when:

• one of the required artifacts is missing → resume from the missing step (Step 2 extract, Step 3 metadata, Step 4 spec, Step 5 cleanup, Step 6 logos/QR)
• the user explicitly requests it ("re-extract", "regenerate the spec", "force", "fresh", "from scratch"). In that case, delete or back up the existing <outdir>/ first so the cache check doesn't fire.

Step 1 — Validate the PDF path and pick an outdir

Required argument: path to a .pdf file. If the file doesn't exist or isn't a PDF, abort with a clear message.

Default outdir convention: outdir = <input_pdf_dir>/<pdf_stem>/ — a folder under papers/ named after the input PDF's basename (no extension). Example: /work/job/ResearchStudio-Reel.pdf → /work/job/ResearchStudio-Reel/. The caller may override with an explicit outdir argument.

Create <outdir>/ if missing.

Step 2 — Extract text + figures + captions

python scripts/extract_pdf.py <pdf> --outdir <outdir>

Writes:

• assets/meta/text.txt — full text via pdftotext (page breaks preserved as \f).
• assets/meta/captions.json — [{page, label, text}, ...] per detected "Figure N: ..." caption.
• assets/meta/figures.json — [{file, width, height, page, layout}, ...] per extracted figure raster.
• assets/figures/<page>_figure<n>.png — raster crop at zoom=6 (~432 dpi). The extractor uses a column-aware boundary heuristic + 50 px symmetric padding around the detected figure region so subsequent Step 5 cleanup has room to work.

Figures — choose the source by priority (DO THIS; it is the biggest time/token saver). The paper's ORIGINAL figure graphics are already clean (no baked caption strips, no column-text bleed) and skip the whole Step 5 crop loop (~6 min + heavy tokens). scripts/source_figures.py fetches them and writes assets/figures/*.png + figures.json in seconds:

1. Provided image links (FIRST): the user attached/linked figure images → python scripts/source_figures.py --images <url|path> … --outdir <outdir>
2. arXiv (RECOMMENDED): the paper is on arXiv → python scripts/source_figures.py --arxiv <id|url> --outdir <outdir> (downloads arxiv.org/e-print/<id>, parses the .tex figure order + captions, rasterizes each graphic).
3. Backup (ONLY if 1 & 2 don't apply, or source_figures.py exits non-zero): the PDF crop path below — full extract_pdf.py (with figures) + Step 5 crop_figure.py.

If source_figures.py succeeded (exit 0): run extract_pdf.py <pdf> --outdir <outdir> --no-figures (text.txt + captions.json ONLY) and SKIP Step 5 (crop_figure.py) entirely — the source graphics are already clean. Otherwise run the full extract_pdf.py <pdf> --outdir <outdir> (with figures) and do Step 5.

Appendix figures — skipped by DEFAULT. Process main-body figures only. From text.txt, find where the appendix / supplementary material begins (the first Appendix / Supplementary heading, or A. / B. / S1… content after References) and note its \f-delimited page. Drop every figure on or after that page — delete the PNGs from figures/ and their rows from figures.json before Step 5, so neither the cleaning loop nor any downstream renderer sees them. Override only when the user explicitly asks — e.g. "include the appendix figures" or naming a specific supplementary figure.

Step 3 — Parse paper metadata

Read text.txt's first page + (if the PDF is from arxiv) the arxiv abs page via WebFetch. Synthesize <outdir>/assets/meta/metadata.json:

{
  "title": "...",
  "authors": ["First Last", "Second Author"],
  "author_index_map": {"First Last": [1, 2], "Second Author": [2]},
  "institutes": ["First Institute", "Second Institute"],
  "venue": "NeurIPS 2025",
  "paper_url": "https://arxiv.org/abs/...",
  "code_url": "https://github.com/..."
}

• authors — display order from the PDF byline.
• author_index_map — author → list of 1-indexed institute indices (matches the superscripts in the PDF byline).
• institutes — semicolon-separated list, deduplicated, in the same order as the numeric indices used in the Authors line (so index 1 = first institute, etc.).
• venue — the real publication venue: conference / journal short name + year ("NeurIPS 2025", "ICLR 2026", "TPAMI 2026"). NEVER write "arXiv" (or "Preprint") as the venue — arXiv is a preprint host, not a publication venue. A paper on arXiv is almost always also published at a conference/journal; find that real venue: check the arXiv abs page's Comments and Journal ref fields (e.g. "Accepted at NeurIPS 2022"), the paper's first-page banner ("Published as a conference paper at ICLR 2024"), or an OpenReview / proceedings listing. For a workshop paper, use the parent conference (a NeurIPS 2022 workshop poster → "NeurIPS 2022"). Only when no real venue can be found anywhere, leave it an empty string (the header then shows no venue badge) — but still never "arXiv".
• paper_url — arxiv abs link (preferred) or publisher landing page.
• code_url — optional; omit field if no code is released.

Step 4 — Synthesize the 9-section paper_spec.md

Write <outdir>/assets/meta/paper_spec.md with the canonical 9 sections, each carrying three subfields (Necessary / Additional / Audio script) plus a YAML preamble:

---
title: <paper title>
authors: <First Last¹, Second Author¹², ...>
institutes: ¹First Institute; ²Second Institute
venue: <venue or empty>
paper_url: <url>
code_url: <url or empty>
title_audio_script: <one-paragraph spoken intro>
---

## Problem
**Necessary:** <≤40 words, the gap this paper addresses>
**Additional:** <≤40 words, supporting context>
**Audio script:** <one paragraph>

## Motivation
...

## Contribution
...

## Method
...
**Key equation:** `$<core formula(s) as clean LaTeX>$`  <!-- 1–3 max: the objective / loss / governing equation that defines the method; transcribe symbols faithfully from text.txt, never fabricate; omit this subfield only if the paper genuinely has no formula -->

## Dataset / Benchmark
...

## Key Result
...

## Ablation Study
...

## Headline Numbers
...

## Takeaway
...

Section-by-section guidance:

1. Problem — 1–2 sentences naming the gap. Additional for context.
2. Motivation — 1–2 sentences for why now. Additional for the failure pattern of prior work.
3. Contribution — 1–3 sentences listing what this paper actually contributes. May be omitted by downstream renderers; still write it here.
4. Method — 2–4 sentences describing the proposed approach, in the paper's own vocabulary. Add a **Key equation:** subfield transcribing the paper's 1–3 core formulas (objective, loss, or governing equation) as clean inline LaTeX ($…$) — this is the single biggest gap downstream posters have versus author ground-truth. Copy symbols faithfully from text.txt; never invent. Omit the subfield only for genuinely formula-free papers (pure systems / empirical).
5. Dataset / Benchmark — describes the data the paper introduces OR uses standard benchmarks (renderers decide whether to render this section).
6. Key Result — the headline experimental finding in 1–3 sentences with the actual numbers.
7. Ablation Study — 1–3 sentences naming the most informative ablation rows. Omit if the paper has no ablations.
8. Headline Numbers — 1–4 metrics that summarize impact. Quantitative, traceable to text.txt — NEVER invented.
9. Takeaway — 1–2 sentences a passerby could repeat after one read.

Audio script subfields are full-sentence spoken paragraphs (3–6 sentences each) suitable for TTS. They are part of the spec because audio narration of any downstream rendering should be derivable from this single source.

Step 5 — Clean ALL figure images (mandatory on the crop path — SKIPPED when source figures were used)

Skip this entire step if Step 2 sourced the ORIGINAL figures via source_figures.py (arXiv source bundle or provided image links) — those graphics are already clean. Step 5 runs ONLY on the crop-path fallback (figures cropped from the rendered PDF).

Step 2 produces raw figure rasters that often carry:

• A 1–10 px chrome residue at the top edge (the bottom of a page rule line / banner / running title that the extractor's column-aware boundary couldn't perfectly avoid).
• A baked-in caption strip at the bottom (rare — extract_pdf.py already clamps to cap_full.y0 - 1, but a few papers have caption text fused into the figure raster).
• A uniform white margin of arbitrary thickness around the cleaned content (a side effect of the 50 px symmetric pad in Step 2 + caption-clamped tight tops).

Downstream renderers should receive cleaned figures, not raw extracts, so we run the deterministic cleanup pipeline on every figure here — independent of which figures any downstream actually picks. Cost is sub-second per figure × 3 commands × N figures = negligible. Skip this entire step when the figures were pre-supplied (Step 2's "already supplied?" branch): original source graphics carry none of the chrome / caption-strip / margin defects below.

For each figures/<file>.png, run 5a → 5b → 5c in this exact order:

5a. top-check — strip top chrome residue.

python scripts/crop_figure.py top-check <outdir>/assets/figures/<file>.png

Pattern-matches the chrome signature (1–15 px non-clean prefix + ≥3 px clean gutter + sustained figure content below). On TOP-CHROME DETECTED — ... cut at y=Z, re-run with --apply to strip. On TOP clean — ..., skip to 5b.

5b. decaption — strip baked-in bottom caption strip (when present).

python scripts/crop_figure.py decaption <outdir>/assets/figures/<file>.png

Fires only when there's a 1–3 line text band at the bottom separated from the figure body by a clear horizontal whitespace gap. Most figures won't trigger. On DETECTED bottom caption band, re-run with --apply. Otherwise skip to 5c.

5c. autotrim — strip remaining uniform white margins (always last).

python scripts/crop_figure.py autotrim <outdir>/assets/figures/<file>.png

Strips border rows/cols that are 100% near-white, keeping a --pad 4 margin. Safe — never touches content pixels. Must come AFTER 5a/5b — autotrim stops at the first dark row, so any uncut chrome/caption traps a thick whitespace band that autotrim cannot reach.

All three modes write figures/_debug/<file>.png.bak (one-shot, never clobbered on re-runs) and update figures.json width/height. The top-level figures/ directory keeps only the in-progress clean PNG — backups and other debug artifacts live in the hidden _debug/ subdir so downstream consumers see a clean listing.

5d. Visual AI cropping review (mandatory, runs on every figure). The deterministic chain in 5a-5c handles uniform white margins, the chrome-residue pattern at the top edge, and the baked-in caption-strip pattern at the bottom edge. It does NOT handle:

• Surrounding column body text leaked into the bbox — when extract_pdf.py's figure-region detection over-reaches into the paper's prose (a vertical strip of column text running alongside the figure, or a few lines of body paragraph above the figure). This is the most common defect, and it's invisible to autotrim/decaption: that text isn't a uniform white margin and isn't a thin caption sliver — it's real ink that paints similarly to figure content.
• Caption text not caught by decaption's thin-strip pattern — captions that are tightly butted against the figure body, or captions that span 4+ lines (decaption refuses on caption blocks taller than ~15% of figure height to avoid amputating real figure content).
• Adjacent-figure bleed on multi-figure pages — a vertical strip of the neighboring panel.

These defects need visual judgment to identify and cut, but eyeballing alone is too coarse — visual estimates routinely miss small panel titles ("mAP", "AP_50"), under-include axis labels by ~50 px, and over-trust gaps that turn out to be content boundaries. So 5d's workflow grounds the visual judgment in two deterministic tools that turn "where exactly is this figure?" into a falsifiable, pixel-level question.

paper2assets owns this responsibility because:

1. Downstream renderers (paper2poster, paper2blog, paper2audio, paper2video) all want figures with only the figure's own visual content — surrounding paper text and captions are noise for every renderer.
2. Doing it once here is cheaper than each downstream re-doing it on its picks.
3. The MAIN "Figure N: …" caption is NEVER part of the figure raster. Its text is already in <outdir>/assets/meta/captions.json as structured data; baking those pixels into the PNG duplicates content and visually collides when downstream HTML/blog renderers add their own <figcaption>. Panel sub-captions like "(a) Pipeline overview" / "(b) Loss curves" are different — they label individual sub-panels, are part of the figure's visual content, and they STAY INSIDE the raster. Rule of thumb: if cutting it would leave the panels unlabeled, KEEP IT; if cutting it just removes a "Figure N: …" prose sentence already in captions.json, CUT IT.

Workflow per figure (after 5a-5c have run): the four steps below — analyze → judge → mark → verify → crop — exist as one loop so the bbox decision is committed only after a deterministic-grounded check AND a visual recheck both pass. Skipping the mark step (going straight from judge → crop) is the loop's most common failure mode: visual estimates from a downsampled Read are coarse, and a mis-estimated bbox commits a destructive crop in one shot. Mark first; commit only when the red box visibly encloses what you want.

Process figures STRICTLY sequentially, ONE figure at a time end-to-end (hard rule). Do not batch — do not run round-1 on all figures and then round-2 on all figures, do not invoke multiple sub-agent verifiers in parallel, do not Read figure A while reasoning about figure B's bbox. For each figure: complete every step (5d.i analyze → 5d.ii judge → 5d.iii mark → 5d.iv self-check + sub-agent verify ≥2 cycles → 5d.v commit), THEN move to the next figure. Cross-figure batching introduces two failure modes — sub-agent prompts can pick up the wrong figure's marked PNG (cross-context bleed), and your own per-edge reasoning can hallucinate elements from a sibling figure into the figure under judgment (cross-figure attention contamination). The cost of strict serial processing is real (no parallelism), but the verifier ambiguity it eliminates is worth it for correctness on every figure.

Step 5d.i — Analyze (deterministic, grounds the bbox decision in pixels):

python scripts/crop_figure.py blocks <outdir>/assets/figures/<file>.png

Prints the figure's ROW + COL ink-block structure (every dense band, every gap between bands, in pixel coordinates) plus heuristic hints flagging narrow blocks adjacent to the main body as "INCLUDE in bbox" (axis labels / legend / rotated y-title) versus blocks separated by a wide (>50 px) gap as "EXCLUDE unless visual recheck confirms it's figure content" (likely body-text column or adjacent figure). This output tells you exactly where each structural part of the figure sits in pixel space — no eyeballing dimensions.

Step 5d.ii — Judge a tight bbox (X0, Y0, X1, Y1) (PIL convention: top-left origin, x1/y1 exclusive). Apply these rules of inclusion ↔ exclusion:

Pattern in blocks output	Decision
Narrow LEFT/RIGHT col block with ≤30 px gap to main body	KEEP — almost always axis labels, a rotated y-axis title ("Accuracy (%)"), or a legend
LEFT/RIGHT col block with >50 px gap to main body	CUT — paper text column (left page-margin) or an adjacent figure bleed
TOP row block separated from the main figure body by a clean gutter, ≤6 px thick	CUT — likely chrome residue (5a should have caught it; this is a backup)
TOP row block separated by a clean gutter, larger	INVESTIGATE — could be a banner ("Published as a conference paper at ICLR 2025") OR could be the figure's actual top legend / panel-title row
TOP small-text region with no clear gutter into the body	INVESTIGATE — could be body-text fragment from above the figure OR could be small panel titles ("mAP", "AP_50") that didn't hit the dense threshold
BOTTOM row block matching "Figure N: ..." pattern (1–3 short rows after a clear gutter)	CUT — main figure caption, already in captions.json
BOTTOM small row blocks matching "(a) " / "(b) " / "(c) " pattern positioned right below each subplot	KEEP — sub-captions label the panels and belong with the figure
Wide ROW gap (>200 px) at the top with no ink above it	The figure body starts where the first ink begins — pad y0 up by 20–30 px to catch small panel titles that fall below the 5% dense threshold
Any visual element straddling an edge (a column, row, panel, legend item, label cluster, sub-caption, bar in a chart)	NEVER a fractional capture. The element must be ENTIRELY inside or ENTIRELY outside the bbox. A half-included element is worse than full exclusion — it shows a confusing partial thing instead of a clean omission. If the rightmost column is "mostly" in but the right edge cuts the last 10% of it, extend the right edge to capture all of it OR pull the right edge in further to exclude it cleanly.

The three single most-common mistakes are (a) cutting the axis-label / rotated-title col block on the LEFT because it looks like a separate structure, (b) setting y0 exactly at the first dense row, which lands inside the panel-title text instead of above it (fix: pad y0 up 20–30 px), and (c) capturing a fractional element at the right or bottom edge — usually a multi-column diagram's last column shows only its header but the right edge cuts the body, or a 4-row stat grid shows only the first 3 rows with the 4th half-visible.

Step 5d.iii — Mark + Preview (verification gate, never destructive):

python scripts/crop_figure.py mark    <outdir>/assets/figures/<file>.png --box X0 Y0 X1 Y1
python scripts/crop_figure.py preview <outdir>/assets/figures/<file>.png --box X0 Y0 X1 Y1

Run BOTH commands per round — they produce a paired set:

• figures/_debug/<stem>.marked-<NN>.png — the ORIGINAL raster with a red rectangle overlay showing the proposed bbox. Used by your own per-edge sanity check (Step 5d.iv) because the red line shows where the cut WOULD happen.
• figures/_debug/<stem>.preview-<NN>.png — the cropped image (i.e. what the final figure WOULD look like if this bbox is committed). Used by the sub-agent verifier (Step 5d.v) because there's no geometry to interpret — the preview IS the proposed result.

Both files rotate suffix (-01, -02, ...) in lockstep so round-N's mark and preview pair together. The original PNG is untouched by either command.

Step 5d.iv — Re-Read the marked image and verify per-edge. Look at the latest figures/_debug/<stem>.marked-<NN>.png and answer four explicit yes/no questions — one per edge. The red box is outside the bbox, so what's INSIDE the box (the content you'll keep) is unobstructed:

• TOP edge: is everything above the red line truly noise (banner, body-text, top chrome)? Are any panel titles ("mAP", legend) sitting just below the line that you mean to keep?
• BOTTOM edge: is everything below the line a "Figure N: …" caption or paper text? Are any sub-captions "(a) …" / "(b) …" / "(c) …" sitting below the line that should be inside the box?
• LEFT edge: is everything left of the line a body-text column from the paper? Are any axis labels / rotated y-axis title / legend column sitting outside the line that should be inside?
• RIGHT edge: same — body-text vs in-figure (legend on the right of a chart, color bar, etc.).

If any answer flips (something you meant to keep is outside the box, or something you meant to cut is inside), adjust the bbox and re-mark.

Conditional iteration: round 2+ only when round 1 verifier wasn't a clean PASS. Round 1 is always mandatory (mark + preview + sub-agent verify). For round 2+:

• If round 1's verifier returned a clean PASS (all of R1–R7 OK, each citing STEP A justification, no ambiguity), commit and stop — running a forced second round when the first attempt is already correct invites the agent to "fix" something not broken, which often introduces a regression (e.g. shifting the box to include a caption it had cleanly excluded).
• If round 1 returned FAIL OR had any rule answered ambiguously (e.g. "OK probably", missing STEP A citation, suggesting a correction even on a stated PASS), adjust the bbox per the verifier's suggestion (single-edge extend / single-edge contract / R7 translation shift), produce a fresh mark + preview pair (-02), and re-invoke the sub-agent verifier on the new preview. Iterate until clean PASS.

Why conditional rather than always-≥2: forced second rounds on already-correct first attempts are net-negative (regression risk > confirmation value). Conditional iteration keeps quality on the table only when needed.

Cap at 5 cycles per figure for genuinely hard cases. Mark + preview are cheap (pure file I/O, no API cost); the sub-agent call is the actual cost driver.

MANDATORY independent verification by a sub-agent (hard rule, not a suggestion).

Your own per-edge check above is biased: you just decided the bbox seconds ago, so your verification is anchored on that decision. You can't reliably catch over-crops (cutting into figure content) or under-crops (leaving noise) by self-review alone — the verifier and the decider need to be different.

So after marked-01 and your own per-edge check, invoke an independent verification sub-agent via the Task tool to recheck the bbox. The sub-agent runs in a fresh context — no anchoring on your bbox decision, no prior beliefs about which edges "should" be where. It is the only check that can catch what your own re-Read systematically misses.

Task(
  subagent_type="general-purpose",
  description="Verify figure crop bbox",
  prompt="""You are an independent figure-crop verifier. The caller has produced
a proposed crop of a paper figure raster. Your job is to judge whether the proposed
crop is correct — by direct visual comparison of two images.

IMAGE 1 (the ORIGINAL, uncropped extract):
  <outdir>/assets/figures/<stem>.png

IMAGE 2 (the PREVIEW — what the figure WOULD look like if this bbox is committed;
this is just IMAGE 1 cropped to the proposed bbox, no annotations):
  <outdir>/assets/figures/_debug/<stem>.preview-<NN>.png

Read BOTH images. The judgement is a direct comparison: 'is IMAGE 2 a clean,
complete version of the figure in IMAGE 1?' There is no red rectangle to
interpret, no inside/outside geometry to puzzle over. You see what the
caller proposes to keep (IMAGE 2) alongside the original (IMAGE 1), and you
judge the difference.

STEP 0 — Grounding (mandatory; never skip). Before any rule check, plainly state:
  - IMAGE 1 dimensions: W₁ × H₁ px. What it contains overall (one sentence).
  - IMAGE 2 dimensions: W₂ × H₂ px. What it contains overall (one sentence).
  - The visible difference: what content does IMAGE 1 contain that IMAGE 2
    has cut away? (e.g. 'IMAGE 1's top ~110 px (a page banner) is absent
    from IMAGE 2', 'IMAGE 1's right ~430 px (an adjacent Figure 2 column)
    is absent from IMAGE 2', 'IMAGE 1's bottom ~50 px ("Figure 1:" caption)
    is absent from IMAGE 2'). Be quantitative — name approximate pixel
    widths of each cut.
This grounding step anchors you on what the proposed crop actually changes
before any rule-based reasoning.

The figure SHOULD include (these elements MUST be present in IMAGE 2):
- all panels / sub-panels / chart bodies that visually compose the figure
- axis labels, legends, colorbars, in-figure annotations
- sub-captions like '(a) ...', '(b) ...' that sit BELOW each subplot and label it
- decorative borders / frames that are part of the figure's artwork

The figure should NOT include (these MUST be cut away — present in IMAGE 1,
absent from IMAGE 2):
- body-text paragraphs from the surrounding paper column
- the main 'Figure N: ...' caption sitting below the figure body
- page banner / running title / arxiv stamp at the top
- vertical strips of an ADJACENT figure (when two figures share a page row)

CRITICAL — no fractional captures: every visual element (column, row,
panel, legend item, label cluster, sub-caption, bar in a chart, axis tick
set, stat tile) must be either ENTIRELY in IMAGE 2 (kept whole) or
ENTIRELY absent from IMAGE 2 (cut whole). A half-included element at any
edge of IMAGE 2 (e.g. 'IMAGE 2's right edge shows the orange panel
background ending mid-element', 'the rightmost "G" in "118 GB" is
half-cut at IMAGE 2's right edge', 'only 3 of 4 stat tiles are fully in
IMAGE 2 with the 4th half-visible') is the most common failure mode —
flag it as FAIL even if everything else looks right.

STEP A — Per-edge forced description (mandatory; no verdict allowed
before completing this). For EACH of the four edges of IMAGE 2, describe
in concrete words:
  (i) what content sits in the ~50 px strip just inside that edge of
      IMAGE 2 (does it end cleanly, or is it cut?), AND
  (ii) what content sits in the corresponding ~50 px strip of IMAGE 1
       that IMAGE 2 has dropped (is it noise that should be dropped,
       or figure content that should have been kept?).

  TOP edge:
    [IMAGE 2 top ~50 px]: ...
    [IMAGE 1 strip dropped just above IMAGE 2's top]: ...
  BOTTOM edge:
    [IMAGE 2 bottom ~50 px]: ...
    [IMAGE 1 strip dropped just below IMAGE 2's bottom]: ...
  LEFT edge:
    [IMAGE 2 left ~50 px]: ...
    [IMAGE 1 strip dropped just left of IMAGE 2's left]: ...
  RIGHT edge:
    [IMAGE 2 right ~50 px]: ...
    [IMAGE 1 strip dropped just right of IMAGE 2's right]: ...

Be physical and specific — name actual elements, give approximate pixel
distances, commit to whether each element ENDS within IMAGE 2 or CROSSES
the edge.

STEP B — Per-rule check (mandatory; one line per rule). For each rule
below, answer VIOLATED or OK, and if VIOLATED quote the exact line from
STEP A that shows the violation. Do NOT skip rules — answer all in order,
even when obvious:

  R1 (no body-text paragraphs inside IMAGE 2): ___
  R2 (no main 'Figure N: ...' caption inside IMAGE 2): ___
  R3 (no page banner / running title / arxiv stamp inside IMAGE 2): ___
  R4 (no vertical strip of an adjacent figure inside IMAGE 2): ___
  R5 (no fractional capture at any edge of IMAGE 2 — every edge-adjacent
      element ENTIRELY in or ENTIRELY out): ___
  R6 (all figure-content elements present in IMAGE 2 — panels, axes,
      legends, sub-captions, colorbars; nothing critical was dropped
      when going from IMAGE 1 → IMAGE 2): ___
  R7 (no TRANSLATION error — the bbox is positioned correctly, not
      shifted off-center. Symptom: IMAGE 2 has significant white margin
      on ONE side AND content clipped at the OPPOSITE side. If left
      margin is wide and right edge cuts content, the box has the right
      width but is shifted too far LEFT — same with top-vs-bottom): ___

The per-rule answers MUST cite the STEP A descriptions. 'R5 OK because
the figure looks complete' is invalid — only 'R5 OK because STEP A right
line says the orange panel background ends ~10 px before IMAGE 2's right
edge with clean white margin' is a valid answer. 'R6 OK because IMAGE 2
looks like a complete figure' is invalid — only 'R6 OK because IMAGE 1's
right-strip drop contains only adjacent-figure content per STEP A right
line, so nothing critical was dropped' is valid. 'R7 OK because the box
is centered' is invalid — only 'R7 OK because STEP A shows the left
~50 px contains the leftmost panel's edge with ≤10 px margin, and the
right ~50 px contains the rightmost panel's edge with ≤10 px margin,
so the box is positioned correctly, not shifted' is valid.

STEP C — Verdict. Based on STEP B:
1. PASS (every rule OK) or FAIL (at least one VIOLATED).
2. If FAIL, name the rule(s) violated and quote the relevant STEP A line(s).
3. If FAIL, suggest a corrected bbox as concrete pixel deltas relative to
   the current one. Pick the right shape of correction:
   - **Single-edge extend** when an element is missing only on one side:
     'extend x1 by ~30 px to recover the rest of the orange panel
     background per R5'.
   - **Single-edge contract** when noise is leaking in on one side:
     'reduce y1 by ~50 px to drop the "Figure 1:" caption text per R2'.
   - **Translation shift** when R7 fired — when one side has slack
     whitespace and the opposite side cuts content. Apply equal-magnitude
     opposite-direction edits to BOTH edges of that axis, NOT a single-edge
     edit. Example: 'shift box right by ~80 px: x0 += 80 AND x1 += 80
     (per R7 — left has ~80 px white margin, right cuts the orange panel
     mid-element)'. Same pattern for top/bottom: 'shift box down: y0 += N
     AND y1 += N'. A single-edge fix on a translation error makes the
     problem worse, not better — flagging the shift explicitly is the
     only way the caller knows to act on it correctly.

A response without all three steps (description → per-rule check →
verdict) is invalid. The caller will reject any verdict that skips
STEP A or B.

Be specific and concise. The figure caller will act on your verdict directly."""
)

Log the verifier's response immediately after every Task call. Write the sub-agent's verbatim verdict (PASS/FAIL + the specific feedback) to <outdir>/assets/figures/_debug/<stem>.verify-<NN>.txt, where <NN> matches the marked-<NN>.png round it judged (so marked-01.png ↔ verify-01.txt, marked-02.png ↔ verify-02.txt, ...). This is the only auditable trace of what the verifier said and how each round's bbox decision was justified — without it, when a figure's crop trends worse across rounds, there's no way to tell whether the verifier gave bad advice or you misapplied good advice. Use the Write tool — keep the file plain text, include the round number and the bbox the verifier was judging at the top so the file reads standalone.

Wait for the sub-agent's response. Two outcomes:

• PASS → commit the bbox (Step 5d.v).
• FAIL → apply the sub-agent's suggested correction, run mark again (producing marked-02.png), and re-invoke the sub-agent verifier on the new mark. Iterate.

Cap at 5 verifier rounds per figure (the verifier disagreement should converge fast on a sane figure; if it doesn't after 5, accept your best attempt and note the residual in figures.json via a "note" field).

The sub-agent is more expensive than self-check (one extra API call per figure × ~7-20 figures per paper ≈ tens of seconds added). The cost buys catching the over-crop / under-crop class of errors that self-review systematically misses.

Step 5d.v — Commit the crop only after the mark passes verification:

python scripts/crop_figure.py box <outdir>/assets/figures/<file>.png --box X0 Y0 X1 Y1

Overwrites the PNG (preserving the existing figures/_debug/<file>.png.bak from 5a-5c — crop_figure.py only writes .bak once, never clobbered on re-runs) and updates figures.json width/height. All figures/_debug/<stem>.marked-<NN>.png overlays from this figure's mark iterations remain in place as the auditable history of the bbox decision (paper2assets does NOT include them in its output contract; downstream renderers ignore _debug/, and figures.json doesn't list it). The hidden _debug/ subdir is purely a debugging breadcrumb — keeps the top-level figures/ listing clean while preserving full traceability.

Step 5d.vi — Split when the raster packs two independent figures. Some papers compact two unrelated figures side-by-side onto one row to save page space. The extractor pulls them as a single raster, but they are NOT one figure and should not be cropped as one. Signature patterns to recognize:

• LEFT image has its own "Figure N: …" caption text directly below it; RIGHT image extends taller than the LEFT image + its caption (the LEFT caption does NOT extend under the RIGHT image).
• Two distinct sub-captions like "(a) Pipeline overview" / "(b) Loss curves" each pinned under its own panel with a clear vertical gutter separating them at the same column position.
• blocks output shows TWO wide COL blocks separated by a clean gutter (≥30 px), each roughly half the image width, with their own internal structure (each has its own legend / axis labels / sub-caption).

When you spot this pattern, decide one bbox per child figure (each tight per the 5d.ii rules above), mark each, verify each, then commit as a split:

python scripts/crop_figure.py split \
    <outdir>/assets/figures/<file>.png \
    --box X0a Y0a X1a Y1a --suffix a \
    --box X0b Y0b X1b Y1b --suffix b

This produces <stem>_a.png + <stem>_b.png, removes the original PNG, and replaces the original's entry in figures.json with two new entries (inheriting page and layout; new file/width/height per child). The shared .bak of the original raster is preserved as the recovery source for both children.

Downstream renderers see two figures and can pick them independently.

If the visual recheck reveals a structurally impossible crop (e.g. the figure's y-axis labels share an x-range with a body-text column, so any rectangle that includes the labels also includes the body text), accept the best rectangular crop — the trade-off here is "lose axis labels" vs "include some body text"; the lesser evil depends on which is more visually offensive for downstream renderers. Note the residue in a brief "note" field on the figure's entry in figures.json so downstream is aware.

Why this step is mandatory and runs on every figure, not just on picked ones: paper2assets is the single owner of figure cleanup. Downstream renderers shouldn't re-discover surrounding-column-text or baked-in caption artifacts that the upstream stage left in. The cost (one blocks call + 1–3 mark/Read iterations + 1 box per figure, ~7–20 figures per paper) is paid once here instead of N times across renderers.

The inspect mode is helpful for quickly probing a figure's outer dimensions and pure-white border before deciding a bbox:

python scripts/crop_figure.py inspect <outdir>/assets/figures/<file>.png

Step 5e — Final autotrim pass (mandatory, runs on every figure)

For each figures/<file>.png, after 5d has committed its box crop, run autotrim one more time:

python scripts/crop_figure.py autotrim <outdir>/assets/figures/<file>.png

Why this exists as a separate trailing step (not just re-using 5c): 5d's box crop is committed from a hand-picked rectangle that the verifier signed off on visually. Visual judgment is coarse at the pixel level — even a tight-looking bbox routinely leaves 2–10 px of pure-white margin on one or more edges (the verifier's eye smooths over thin uniform-white borders the same way it smooths over the top-chrome residue that motivated 5a). autotrim is the cheap, safe, deterministic mop-up that strips those residues so the saved PNG's dimensions match the figure's actual content extent.

Idempotent + safe:

• If 5d cropped tight (no whitespace left), autotrim prints no border whitespace to trim — left untouched and exits 0 without re-saving. Cost ≈ 50 ms per figure (just a numpy pass over the array).
• If 5d's bbox left a margin, autotrim strips it, keeps the standard --pad 4 margin, writes the .bak (only if 5a/5b/5c didn't already — the one-shot guard protects the original raw extract), and updates figures.json width/height so downstream layout math stays consistent.
• Never touches content pixels — --tol 8 means only rows/cols that are within 8 of pure white from all three RGB channels qualify as "border".

This is the last image-processing step before the figures leave paper2assets. Downstream renderers (paper2poster, paper2blog, etc.) receive content-tight PNGs and don't need to redo edge-trim work.

Step 6 — Fetch institute logos + conference logo + URL QR codes

⚠️ CRITICAL: copy the exact commands below verbatim. The flag names here are trap-prone — a subtle mistake silently drops every logo. Do not hand-edit these commands.

python scripts/fetch_logos.py     --from-spec     <outdir>/assets/meta/paper_spec.md --outdir <outdir>
python scripts/fetch_conf_logo.py --from-metadata <outdir>/assets/meta/metadata.json --outdir <outdir>
python scripts/make_qr.py         --from-metadata <outdir>/assets/meta/metadata.json --outdir <outdir>

⚠️ Flag traps for ALL THREE scripts — DO NOT alter:

1. --from-spec / --from-metadata (NOT --spec / --metadata). argparse rejects the short forms with usage error. We accept --spec / --metadata as compat aliases now, but the canonical flag names are the --from-* forms.
2. --outdir <outdir> is the poster outdir — NOT a /logos or /qr subdir. The scripts append assets/logos/ and assets/qr/ themselves. Passing --outdir <outdir>/assets/logos (or /qr) makes the scripts land files at <outdir>/assets/logos/logos/<slug>.png (nested-dir bug) — downstream paper2poster looks at <outdir>/assets/logos/<slug>.png and finds nothing. The scripts now auto-strip a trailing /logos, /qr, or /assets/{logos,qr} with a warning, but pass the poster outdir cleanly as shown above.

make_qr.py is best-effort (classifies + de-duplicates the paper/project/code URLs into ≤2 QR slots — see the deliverable table). fetch_conf_logo.py and fetch_logos.py are checklist-driven with a MANDATORY web-search fallback — do NOT treat a first-pass miss as final:

6a. Institute logos — checklist, then fallback (logos must NOT be left missing)

The deterministic Wikimedia pass gets the easy ones; obscure / non-English / newly-founded institutes routinely miss it. You MUST close the gap rather than shipping a logo-less header:

1. Run fetch_logos.py (command above). It prints a ✓/✗ CHECKLIST to stderr and a JSON object {"logos": [...], "missing": ["Institute A", ...]} to stdout.
2. Read the "missing" array. For EVERY name in it, run the web-search fallback — this is required, not optional:
   • WebSearch "<institute> official logo png" (try svg, or the institute's English name / acronym expansion if the raw string is a department or non-English name).
   • Pick the official mark from the institute's own site / brand-resources page, Wikipedia/Wikimedia, or an official social profile — skip stock-photo aggregators, third-party redraws, photos, campus/building shots, and flags. WebFetch the page if you need to locate the direct image URL.
   • Download it through the SAME pipeline (autotrim + canonical slug) so it matches the other tiles:

     python scripts/fetch_logos.py --outdir <outdir> \
       --add-logo "<Institute Name>=<direct image URL>"
     

     Repeat --add-logo "Name=URL" for each missing institute (the flag is repeatable).
3. Only after a genuine web search comes up empty for a given institute do you leave it out. Re-run the checklist mentally: every institute now either has a assets/logos/<slug>.png file or was truly unfindable. A logo missing because you skipped the fallback is a defect.

6b. Conference / venue logo — preprints get NONE (never an arXiv mark)

fetch_conf_logo.py fetches the conference's generic mark to assets/logos/_venue.png, best-effort, skipping on any miss (the header then falls back to its text VENUE/YEAR badge).

• If the paper is a preprint with no accepted venue — i.e. metadata.json venue is empty (an arXiv paper where no conference/journal could be found, per Step 3's venue rule) — there is NO venue logo and NO venue badge. Do NOT fetch, download, or fabricate an "arXiv" / "Preprint" mark to fill the slot; leave _venue.png absent so the header simply omits the venue entirely. arXiv is a host, not a venue.
• When venue IS a real conference/journal, fetch_conf_logo.py supplies its mark; if that misses, the text badge stands in (no fallback logo hunt needed for the venue).

Downstream renderers still defensively handle a missing logo / missing qr/code.png, but with the fallback above the institute logos should rarely be missing.

Step 7 — Build the cross-skill canonical package (sections.json + narration.json + manifest.json)

paper2assets is the single source of truth for ALL paper-rendering skills downstream — not just paper2poster. Skills like paper2blog, paper2video, and paper2reel consume the same <outdir>/ and rely on three additional canonical files that paper2poster doesn't need but they do:

• manifest.json — package inventory (file paths + counts + source PDF sha256). Lets downstream verify the package shape without re-walking the directory.
• sections.json — paper_spec.md parsed into structured per-section JSON with stable ids (problem, motivation, method, key-result, ...), the per-section necessary / additional / audio_script fields, and an empty figures: [] per section (downstream joins with figures.json by id).
• narration.json — TTS clip list extracted from **Audio script:** markers, in document order. The title clip comes from the YAML frontmatter's title_audio_script field.

paper2poster ignores these three files (it reads paper_spec.md directly), so this step is additive — generating them does not change anything paper2poster sees.

For each completed <outdir>/, run this exact sequence after Step 6:

python scripts/build_package.py <pdf> \
    --outdir <outdir> \
    --skip-extract \
    --paper-spec <outdir>/assets/meta/paper_spec.md

Builds the 3 canonical JSON files from paper_spec.md + the already-extracted text.txt / captions.json / figures.json / metadata.json.

build_package.py notes:

• --skip-extract is mandatory in this step (extraction is already done by Step 2; without --skip-extract the script would re-invoke extract_pdf.py and overwrite our cleaned figures).
• Parses the paper2assets YAML frontmatter format (---\ntitle: ...\nauthors: ...\n---) for top-level metadata, and the ## Heading + **Necessary:** / **Additional:** / **Audio script:** body sections for per-section content. This matches what Step 2 + Step 4 produce, end-to-end.

Output (added to <outdir>/):

• manifest.json
• sections.json
• narration.json

These are canonical for all downstream paper-rendering skills.

Audio is NOT synthesized here — only the script

paper2assets stops at the narration script (narration.json, Step 7) and the **Audio script:** fields in paper_spec.md. It does not run TTS and produces no audio/ directory. Each downstream renderer synthesizes its own audio from its own source:

• paper2poster runs its scripts/generate_audio.py on <outdir>/assets/meta/narration.json → <outdir>/assets/audio/<id>.mp3 for its Listen buttons (see paper2poster's Step 5).
• paper2video synthesizes per-slide audio in its own stage from the deck's speaker notes (a separate narration source).

Final deliverable check

Before declaring done, verify <outdir>/ contains the required files:

# Step 2 outputs (extraction)
ls <outdir>/assets/meta/text.txt <outdir>/assets/meta/captions.json <outdir>/assets/meta/figures.json \
   <outdir>/assets/meta/metadata.json <outdir>/assets/meta/paper_spec.md
ls <outdir>/assets/figures/*.png

# Step 7 outputs (cross-skill canonical package)
ls <outdir>/manifest.json <outdir>/assets/meta/sections.json <outdir>/assets/meta/narration.json

The optional logos/ and qr/ directories may be empty or absent (best-effort fetch); a downstream renderer is responsible for handling that gracefully.

Print the absolute outdir path on the last line of your reply so the caller (poster_pipeline.sh, batch_titles.sh, or another driver) can pick it up.

Tools

scripts/
├── extract_pdf.py        ← CLI: pdf → assets/meta/{text.txt,captions.json,figures.json} + assets/figures/
├── crop_figure.py        ← CLI: inspect / autotrim / box / decaption / top-check
├── fetch_logos.py        ← CLI: spec → assets/logos/*.{png,svg} (Wikimedia Commons)
├── make_qr.py            ← CLI: metadata → assets/qr/{paper,code}.png
└── build_package.py      ← CLI: assets/meta/paper_spec.md → manifest.json + assets/meta/{sections.json,narration.json}
                            (cross-skill canonical package for downstream renderers)

Key rules

• Step 5 runs on every figure, not just suspected ones. Cost is trivial; missing chrome / trapped margins / surrounding paper text downstream is expensive.
• Step 5 ordering is non-negotiable. top-check → decaption → autotrim → visual AI review (5d) → final autotrim mop-up (5e). 5d sits in the middle because the deterministic chain in 5a-5c handles the easy patterns first; 5d catches what the patterns can't (column body text leakage, asymmetric noise, captions outside decaption's thin-strip pattern). 5e closes the loop by re-running the cheap autotrim after 5d's visually-judged bbox commits — visual judgment leaves pixel-level whitespace residues even when the bbox looks tight, and 5e is the safe deterministic mop-up that ensures saved PNG dimensions match figure content extent.
• Main caption out, sub-captions in. The paper's "Figure N: …" caption is already in captions.json as structured text — if you see that line at the bottom of a figure raster, CUT IT in 5d. Panel sub-captions like "(a) Pipeline overview" / "(b) Loss curves" stay — they label the sub-panels and are part of the figure's visual content; cutting them strips the figure of its own labels. Rule of thumb at the bottom edge: 1–3 short prose rows starting with "Figure N:" → CUT; short "(a)/(b)/(c) " rows pinned right under each sub-panel → KEEP.
• Surrounding column body text never lives inside the figure raster either. A vertical strip of paper prose alongside the figure, or a few lines of body paragraph above/below — all noise. 5d's per-edge check catches them; act on what you can describe in words.
• paper_spec.md is the single source of truth for any downstream prose / narration. NEVER invent numbers — pull from text.txt.
• Best-effort steps (logos/QR) do not abort the workflow. Document the omission; downstream renderers handle missing inputs.
• Cache friendliness: re-running paper2assets on an existing outdir should be safe and incremental. The deterministic crop pipeline (5a/5b/5c) is idempotent — .bak is the original raw extract; re-runs operate on the already-cleaned .png and won't double-cut (autotrim refuses if there's nothing to trim; top-check returns "clean" if no chrome). 5d's visual review is also idempotent on a clean figure: the per-edge yes/no answers will be all "no" and no box invocation fires. 5e's trailing autotrim is by construction a no-op on an already-tight figure (it returns "no border whitespace to trim — left untouched"), so re-runs add a constant per-figure numpy scan with no I/O.