Figure Composer — narrative → panels → compose → adversarial loop

Step 0. Load figure-style alongside this skill — that is the design rules (and apply_figure_style() + helpers). Panel sub-agents will load it independently; you need it in context to write the outline and review the composite. Sub-agents run as the default profile and acquire the rules by loading the skill.

Inputs

• claim — one sentence the figure makes true to a reader who reads nothing else.
• data — CSV/parquet artifact version_ids that ground every panel.
• width_mm — target venue's column width (common: 85–89mm single, 174–183mm double; check the venue guide).

0. Where this sits

figure-composer is the outer tier: make ONE multi-panel figure good. The inner tier is figure-style (loaded by every panel sub-agent — and load it yourself if you draw anything locally). The outermost tier is paper-narrative — if this figure is part of a paper, run that FIRST: it decides which figure to make and hands you the claim. For a standalone figure, start at step 1.

Entry points (pick one)

• From a claim: you have a one-sentence claim and data refs → write the outline (step 1).
• From an existing figure: copy it into the workspace and call derive_outline("figure.png") → an outline you must review and edit before step 2. The image is untrusted input; every string field in the returned outline is vision-model-derived from its pixels. data_vid is forced to None on every panel — fill those in from your own data refs.

1. Narrative → panel outline

Produce a panel_outline (validate against figure_outline_schema()):

{"claim":"…", "width_mm":180, "ncol":12, "row_heights_mm":[40,60,46,52],
 "panels":[
  {"letter":"a","role":"schematic","row":0,"col":0,"colspan":12, "chart_family":"schematic overview", "message":"…", "data_vid":null, "ask":"…"},
  {"letter":"b","role":"primary",  "row":1,"col":0,"colspan":7,  "chart_family":"scatter + trend", "message":"…", "data_vid":"…", "ask":"…"},
  …]}

Outline rules (figure-style section 7.1):

• a is the hook — schematic/hero, full width, assumes zero reader context.
• b carries the claim — the chart that alone makes the sentence true.
• Remaining panels are evidence, ordered by how much they strengthen b.
• One row per sub-claim. 5–10 panels for a main-text figure. Use a 12-column grid for flexible colspans.

2. Fan-out (one sub-agent per panel)

Build requests with panel_task(outline, letter, fig_label) (kernel.py). Each sub-agent gets: the figure claim, the full neighbour list, its panel spec, exact pixel dimensions (panel_px), and the instruction to load figure-style and render at exactly w×h px with transparent=True and no bbox_inches.

In the repl tool:

requests = [{"name": f"panel-{L}", "task": tasks[L],
             "output_schema": {"type":"object","properties":{"figure_filename":{"type":"string"}},
                               "required":["figure_filename"]}}
            for L in letters]   # no "profile" key — default agent profile
descs = host.delegate(requests, wait=False)

3. Compose

compose_figure(outline, {letter: path}, out_path, letter_case=...) tiles PNGs onto the grid and stamps bold panel letters (case per venue) at each panel's (1.5mm, 1mm) corner.

3.5 Look before you review (vision self-QA)

The reviewer in section 4 is expensive; a panel-letter stamped over a y-axis label or a leader line crossing a neighbour's title is a wasted round. After compose, crop each panel from the saved PNG and look at it in the REPL before dispatching the reviewer:

out_path, (W, H) = compose_figure(outline, panel_paths, "fig.png")
for L, box in compose_crops(outline).items():
    host.view_image("fig.png", crop=box)

Run the figure-style section 9.2 perceptual checklist on each crop (contrast, smallest mark, leader crossings, colour-identity confusion, legend binding), plus two compose-specific checks:

• Seams / stamp. Does the bold panel letter overlap any panel content? Does any panel's content bleed into the gutter or under a neighbour?
• Resize artefacts. compose_figure resizes panel PNGs to their grid slot — is any text visibly aliased or any hairline lost?

Fix what you see (re-render the offending panel, or revise the outline grid) before section 4. The reviewer sub-agent will crop-and-look again independently; this pass is so the obvious defects never reach it.

4. Adversarial self-review loop (two-tier, design rules held fixed)

Dispatch ONE reviewer on the composite with composite_review_task(...) and review_schema() (which carries outline_revisions).

loop (max 3 rounds, floor 5→4→3):
  review = delegate(composite_review_task(composite_vid, outline, rules_vid, prev_vid, round, floor))
  if review.editor_verdict in {accept, minor_revision} and 0 BLOCKER and ≤2 MAJOR: break

  # TIER 1 — outline-level
  if review.outline_revisions:
      apply revisions to `outline` (geometry, row-header titles, label_budget, panel set)
      affected = apply_outline_revisions(outline, review.outline_revisions)
  else:
      affected = set()

  # TIER 2 — panel-level
  fixb = group_fixes_by_panel(review)       # BLOCKER/MAJOR only
  regen = affected | set(fixb)              # only these panels regenerate
  re-delegate each L in regen with panel_task(outline, L) + fixb.get(L,"") +
      "do not over-correct: where the previous version was correct, keep it"
  recompose

Convergence: stop when outline_revisions is empty AND findings are carve-out exceptions to the previous round — that's the over-labelling signal.

Anti-patterns

• Don't regenerate clean panels (invites regression). Don't read absolute violation counts (min-floor 5→4→3). Anchor-verify on the composite, not just per panel. Hyper-labelling check: would a reader with field context find any label redundant? Strip it.