"Include a diagram" produced decks with no picture. Three separate faults, each
hiding the next, found by generating the same deck after fixing each one.
First, deck generation ran on the default 4000-token budget. A deck's JSON is
several times the size of the prose it holds, so a long deck came back truncated,
failed to parse, and fell back to markdown — which has no way to request a
figure, so the model described one instead and the slide rendered a literal
"![Placeholder: Flow diagram ...]" as its first bullet. Deck generation now gets
room, and the fallback says how the reply failed: empty, cut short at N
characters, or not a deck.
Second, the figure request sat inside the layout vocabulary, one line among
forty, and the model passed over it. It goes last now, after the author's own
instructions — the same placement lesson the image tool taught earlier.
Third, and the one that actually mattered: image_prompt is only read on the
figure and image types, so an image_prompt on a bullets slide was dropped in
silence. The instruction said "add image_prompt to N slides" without saying
which types carry one. It now names them, and a misplaced request is honoured
rather than discarded — a slide with words becomes a figure, one without becomes
a full-slide image.
Image markup is also stripped wherever text enters a slide, on both paths: a
described figure is not a figure, and a bullet of raw markdown is worse than no
bullet.
Verified end to end after: the same request produced a deck with one figure, the
job completed, and the exported pptx carries one embedded image across 21 slides.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Dv6sqaY6Vq3ChZHMem3cnU
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