Gotchas

Common failure modes for the canva-creator skill.

Gotcha: Generating ANY Canva design for an email row

Why it matters: Canva is out of scope for the email path entirely. Canva email-template autofill produces placeholder graphics (stock landscapes, blank rectangles) in service-grid tiles, and variation thumbnails fail to render in chat. Emails are text-only from this skill, period. Generating a Canva email design — even one — breaks that rule.

✗ Bad

Calendar has 6 social rows + 2 email rows.
→ Stage 2 generates 6 social designs + 2 email designs.
→ Email designs ship with placeholder service tiles.

Or any variation: "I'll generate the email template just to give you a visual reference," "I found an email template that might work, want to preview it?", "Here's a Canva design for the Jun 5 email…" — all forbidden.

✓ Good

Stage 1: Calendar built with Path column.
  - 6 rows tagged Canva (social)
  - 2 rows tagged Text-only (no Canva)
Stage 2: Generates exactly 6 Canva designs. Email rows are not passed
         to any Canva endpoint.
Stage 3: Drafts 6 social captions + 2 full emails (subject + preheader +
         body) as plain text.
Stage 4: Stages 6 social posts in HubSpot. Surfaces 2 emails inline for
         owner to copy into their email tool.

If the owner explicitly asks for a Canva email design ("can you make me a Canva version of the Jun 5 email?"), redirect: "This skill keeps emails as text-only because the Canva email path produces placeholder graphics. If you want a Canva-designed email, build it directly in Canva and I can help you write the copy here."

Gotcha: Generating without a budget plan

Why it matters: Canva caps API usage at 100 requests/minute per token, and each design costs ~5 calls (autofill + export + polling). A 10-row campaign with 4 candidates per row generates 40 designs and ~200 API calls — and the math gets worse with parallelism. Without a pre-flight budget, the owner hits quota mid-campaign with no clear recovery path and four already-generated posts sitting unused.

✗ Bad

Calendar approved → immediately fire 4 candidates × 8 rows in parallel
→ ~160 API calls in 90 seconds → RATE_LIMIT_EXCEEDED on post 5 → loop
on retry → owner blocked.

✓ Good

Pre-flight: "8 Canva rows × 3 candidates = 24 designs, ~120 API calls.
Proceed at default 3 candidates per row?"

Stage 3: row 1's 3 candidates fire in parallel → 30s pause → row 2 →
30s pause → row 3 → … finishes at ~12 designs/minute, well under the
quota.

If quota does hit anyway: stop, surface progress, ask the owner
whether to drop to single candidates, pause an hour, or move to
captions with what's done.

Gotcha: Skipping Checkpoint 1 (calendar approval) before generating assets

Why it matters: Generating 10+ Canva designs takes API calls, time, and user attention. If the calendar has the wrong dates, wrong channels, or the owner changes their mind about a theme, all that work is discarded. The calendar checkpoint is the cheapest place to catch misalignment.

✗ Bad

Receive the brief → immediately start calling POST /autofills for all 12 posts → present designs before the owner has agreed on the schedule.

Owner: "Oh wait, I didn't want any posts the week of the 15th, I'm traveling."

✓ Good

Present the calendar table first. Wait for explicit "looks good" before opening a single Canva API call.

Gotcha: Template has more image slots than the brief provides photos for

Why it matters: Multi-image social templates (Instagram carousels, product grids) can have 3+ image slots. When the brief gives you 1 photo and the template demands 3, the unfilled slots silently render Canva's stock landscape graphic — generic clouds and green hills where product photos should be. The design looks "complete" until the owner opens it.

(Note: email rows skip Canva entirely in this skill — see SKILL.md Stage 3. This gotcha applies only to social templates with multiple image slots.)

✗ Bad

Build manifest with one row per design ("Carousel — needs Hero_Image"). Upload the one photo. Generate. Carousel ships with slide 1 populated and slides 2-3 both showing identical generic landscapes.

✓ Good

Build manifest slot-by-slot. Surface the gap explicitly:

The "3-product carousel" template has 3 image slots. The brief gave me
1 photo. How should I fill the other 2?

1. Reuse the same photo across all 3 slots
2. I'll send you 2 more photos
3. Pick a single-image template

Wait for the owner's choice before generating. Don't let placeholder graphics ship.

Gotcha: Trusting status: success without exporting and visually verifying

Why it matters: A successful autofill job means Canva accepted the request and produced a design — not that the design contains the right images. If an asset_id was empty, stale, or wrong-typed, the job still returns status: success and the design renders with default placeholder graphics. The only way to know is to look at the rendered output.

✗ Bad

Job status: success ✓
result.design.id: present ✓
→ Present to owner

Result: owner opens the carousel and sees stock landscape graphics in 3 of 4 designs.

✓ Good

After the job succeeds, export each design to a permanent PNG via POST /exports (or export-design MCP). Look at each PNG and confirm it contains real assets — not Canva's default landscape, not gray rectangles, not lorem-ipsum text. Only present to the owner after visual verification passes.

Gotcha: One design in a batch fails to render

Why it matters: When 1 of 4 designs in a batch fails (job error, expired preview URL, placeholder rendered) and you present the partial carousel anyway, the owner sees three real designs and one "Show Image" gray rectangle. They lose trust in the rest of the carousel even though it's fine.

✗ Bad

Week 1 designs are ready:
[Option A — real preview]
[Option B — real preview]
[Option C — real preview]
[Option D — Show Image placeholder]
Which one should I use?

✓ Good

When you detect the broken design at Step 6 verification, regenerate just that one design with the correct asset_id. Re-export, re-verify. Only present once all four designs in the batch have permanent, verified previews. If the second attempt also fails, ask the owner whether to skip, swap template, or try a different photo.

Gotcha: Generating assets without confirming all autofill fields have values

Why it matters: Canva autofill silently renders empty placeholders when a field value is missing or the referenced asset_id doesn't exist. The result is a professional-looking template with blank white rectangles where the product photo and headline should be.

✗ Bad

Build calendar → immediately fire all POST /autofills in parallel → half the designs come back with empty image placeholders because product photos weren't uploaded first.

✓ Good

Build calendar → inventory every autofill field slot-by-slot → upload missing product images → confirm all field values with owner → then generate designs in parallel, with every field pre-populated.

Gotcha: Passing invalid values to image autofill fields

Why it matters: When an autofill image field receives an empty string, a file path, a URL, or a stale/invalid asset_id, Canva does not error — it silently renders the template's default placeholder graphic (e.g., a generic landscape with clouds and hills). The design looks "finished" but the hero image is stock art, not the owner's product photo.

✗ Bad

Upload product photo → don't wait for the upload job to complete → pass the job_id (not the asset.id) into the autofill data → design renders with a placeholder landscape instead of the product photo.

✓ Good

Upload product photo via POST /v1/asset-uploads → poll GET /v1/asset-uploads/{job_id} until status == "success" → extract asset.id from the response → pass that exact ID into the autofill image field. Verify every image field has a confirmed asset.id before calling POST /autofills.

Gotcha: Embedding Canva CDN thumbnail URLs in markdown

Why it matters: Canva's autofill response returns short-lived, authenticated CDN URLs from design.canva.ai. These expire within minutes. If Claude embeds them as markdown images (![](design.canva.ai/...)), they render as broken "Show Image" placeholders by the time the message is shown.

✗ Bad

Generate 8 designs → manually embed each CDN thumbnail URL in the response as ![Hero 1](https://design.canva.ai/xxx) → all images show as broken gray placeholders because the URLs expired before render.

✓ Good

Either let the native Cowork carousel render the tool result automatically, or export each design via POST /exports and embed the permanent export URL. As a final fallback, link to the design's permanent edit URL (https://www.canva.com/d/{design_id}). Never re-embed design.canva.ai URLs.

Gotcha: Listing designs one-by-one as individual image blocks

Why it matters: When Claude lists each design as a separate block ("Hero 1 / [image] / Hero 2 / [image]"), the images render as broken gray "Show Image" placeholders. Presenting all designs together in a single grouped batch triggers Cowork's side-by-side carousel, which renders correctly.

✗ Bad

Hero 1 — Multi-property portfolio
[Show Image]
View in Canva: https://canva.com/d/xxx

Hero 2 — Coastal market case study
[Show Image]
View in Canva: https://canva.com/d/yyy

✓ Good

Present all designs in one grouped response so they render as a side-by-side carousel. Below the carousel, add a single prompt:

Here are 4 hero designs for Week 1. Scroll through the carousel
above and let me know which one to keep.

Gotcha: Generating designs sequentially instead of in parallel

Why it matters: Generating designs one at a time means the owner waits through N round trips instead of one. Fire all generation requests within a batch at once and present selection after all jobs complete.

✗ Bad

Generate design 1 → wait → show it → generate design 2 → wait → show it → … × 8 designs. Owner watches a slow drip for 10 minutes.

✓ Good

Fire all designs in the current batch at once → poll all jobs concurrently → once all complete, export each → verify visually → then present.

Gotcha: Auto-selecting a brand template for Pro/Teams users

Why it matters: Pro/Teams users have no brand-template API access. If Claude guesses a template by name and generates with the wrong one, the owner gets designs in the wrong colors/fonts and has to redo the work in Canva manually.

✗ Bad

Found template "Square Post - Blue". Using this for all feed posts.

…followed by 8 designs in blue when the brand is green.

✓ Good

I found 3 templates in your Canva library that could work for feed posts:
1. Square Post - Blue  (last edited March 2026)
2. Summer Promo - Green  (last edited April 2026)
3. Product Feature Card  (last edited Jan 2026)

Which one should I use?

Gotcha: Caption voice drift across a long calendar

Why it matters: When drafting 12–20 captions in one pass, the tone tends to drift — early captions follow the brief's voice markers, later ones slip into generic marketing copy. Owners notice immediately.

✗ Bad

Post 1: "Our handmade candles are the perfect summer gift 🌿" (matches brief: "warm, conversational") Post 10: "Elevate your ambiance with our artisanal fragrance collection." (corporate drift)

✓ Good

Before drafting, anchor on 2–3 voice markers from the brief (e.g., "casual, friendly, uses light humor"). Re-read the first draft caption before writing each new one. If the owner flags a voice mismatch on any caption, re-read that caption and flag it as the recalibration point for the remaining drafts.

Gotcha: Staging HubSpot posts without verifying scheduledAt is in the future

Why it matters: HubSpot rejects posts with scheduledAt in the past with a validation error. If the calendar was built on an earlier date and the owner is only now staging, some dates may have passed.

✗ Bad

Build calendar on April 1st for June posts → owner approves May 15th → try to stage without checking → post for "April 30th 10:00 AM" returns 400.

✓ Good

Before calling POST /social/posts, compare each scheduledAt against the current UTC time. If any post date has passed, surface it: "The post scheduled for April 30th has already passed. Should I skip it, or reschedule it to next week?"