open-design-poster

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Design a poster with Open Design, check it, and export files that are ready to print or post.

Brief: "$ARGUMENTS" — or, if that is empty, the user's request in this conversation (if it isn't clear, ask the user: "What is the poster for, and is it for print (which size) or screens?")

How to talk to the user. Many people using Open Design don't write code, so:

• Use the user's own words. If they say "artifact", "design tokens" or give a file path, use those terms back; otherwise use the plain words below.
• Keep the machinery out of replies: no tool names, no ids like od:prototype:poster-hero, no internal files (.artifact.json, .comments.json, config.json), and not the words "register", "manifest", "sidecar", "entry" or "surface", unless the user used them first.
• Explain a print term the first time it comes up, in one short clause, and not again.
• Say where a file is the way the user would find it ("in your Open Design folder, under seed-swap-flyer"). Give a raw path only where the user can click it (Claude Code, Claude Desktop's Code tab, VS Code) or asks for it.
• End each reply that finishes a step with one line on what they can do next, with at most two options ("Want it in Instagram sizes too, or is it ready to print?").

Instead of	Say
artifact, entry, registered	your design, saved
design system, active design system	your style (the first time: "a saved style: colours, fonts and spacing")
surface, skill, template, recipe	kind of design, starting layout, or nothing
workspace, output directory	your folder, your Open Design folder
bleed	print edge ("a few millimetres extra that the printer trims off")
trim size	final size
preflight findings, errors	"I checked it and fixed…", "one thing to look at:"
export	save as PDF, save as an image
inline preview, MCP App	the preview above

1. Pick the medium and a default shape

Decide whether this is for print or screens. If the brief doesn't say, ask the user before doing anything else. Don't guess between print and screen: the units, bleed and type sizes are different.

You don't need the final size yet. The poster is built fluid: it reflows to any shape, so the user can pick or change the size later, when exporting. Use the size the user names as the default shape; otherwise use a3 for print and ig-portrait for screens, and tell the user they can change it at any time.

Use	Format id	Size
Print, small: flyer, handout	a4 · letter	210×297 mm · 8.5×11 in
Print, medium: notice-board poster	a3 · tabloid	297×420 mm · 11×17 in
Print, large: wall poster	a2 · a1 · poster-18x24 · poster-24x36	420×594 mm · 594×841 mm · 18×24 in · 24×36 in
Print, conference or research poster	a0	841×1189 mm
Instagram portrait	ig-portrait	1080×1350 px
Story / Reels / TikTok cover	story	1080×1920 px
X single image	x-image	1600×900 px
Square (Instagram / LinkedIn)	ig-square	1080×1080 px

A handout and a wall poster carry different amounts of text, so if the user says which it is, write the copy for that; the shape itself can still change.

2. Generate

If the user asked for options ("show me a few directions"), run a design exploration first and build out the direction they pick, with the same format and fluid: true.

Otherwise call prepare_open_design_brief with:

• a skillId: od:prototype:poster-hero for a bold marketing poster, od:prototype:magazine-poster for an editorial or type-led one, or another skill whose style fits better (list_open_design_skills with query "poster");
• the brief, in the user's words;
• format: the default shape from step 1;
• fluid: true.

Call list_open_design_design_systems first if the user names a brand or visual direction, or recommend_open_design_design_systems if they name none and no design system is active.

Author the file yourself, following the returned instructions. Their Canvas section is authoritative: one data-od-card data-od-fluid element sized by --od-w/--od-h, everything inside sized in container units, and layout rules for wide and tall shapes. Also:

• Use real copy from the brief, with no lorem ipsum. A poster is read from a distance: one dominant headline, then the what / when / where, then the call to action.
• If the user gives a list of names, sessions or locations to make one poster each, mark the changing text with data-od-field="<column name>" (and a per-person QR slot with data-od-qr-field="<column>"), and fill the design with the first row's values.
• No external image URLs unless the user supplied them. No emoji as key visuals; draw them as inline SVG.

3. Add a QR code, if it needs one

Register the artifact first (step 4), then call create_open_design_qr_code with the entry path and the URL, and paste the returned inline SVG where the code goes. Never draw a fake or placeholder QR code.

4. Register

Call register_open_design_artifact with the entry path, kind html, a title, sourceSkillId, and format set to the default shape.

5. Check and fix

Call check_open_design_artifact with the entry path. It returns the poster as an image plus preflight findings. Fix every error in its findings (text cut off, overlapping or in the bleed, a QR code that doesn't decode), and fix warnings where you reasonably can (sizes that don't scale with the poster, small type, low contrast, low-resolution images). Look at the image too: the headline should dominate and nothing important should be cramped or cut. Check again until there are no errors (at most two fix rounds; tell the user about anything left).

<!-- claude-only --> Artifact preview. If you have an Artifact tool, publish this design as its private artifact preview once the check is clean: call publish_open_design_artifact with provider: "claude-artifact" and follow what it returns. Publish again after each round of feedback you apply; it goes to the same artifact. Give the link once, then just say the preview was updated. <!-- /claude-only -->

6. Other shapes

When the user wants other sizes, or before the final export of a print piece, call export_open_design_artifact with shapeSheet: true and checkOnly: true (add presets with just the shapes they care about, or leave it out for every shape). It writes one image of the poster at each shape, marking shapes with errors; show it to the user. If you can view images, look at it too: the headline should dominate every shape and nothing important should be cropped.

For a shape that has errors or looks wrong, call adapt_open_design_artifact with the entry path and those format ids. For a fluid poster it returns tune instructions: fix that shape inside the same file with its @container rule, then check every shape again with a shape sheet. Don't create new files for other sizes.

7. Export

• One shape: call export_open_design_artifact with the entry path and preset set to the format id. A print format gives a PDF the size of the bleed box, with trim and bleed boxes set and the bleed added automatically; add cropMarks: true if the user's printer wants crop marks. A screen format gives a PNG within the platform's size limit.
• Several shapes: pass presets with the format ids instead: one file per shape, named <name>-<format>.
• One per row of a list: add data with the workspace path of the user's CSV, XLSX or JSON file, and nameField with the column to name files by. Images come out one per row; print PDFs come out as one multi-page PDF per shape (add split: true for one file per row).

8. Report

List each exported file's path, size and any remaining warnings. For print files, also give the trim size and bleed, and tell the user the PDF is RGB: most print shops convert it, but they should ask if theirs needs CMYK. Mention that the poster can be exported at any other size later without regenerating it. Don't print, post, upload or order anything yourself.