GeezerVison

The break

The new workflow block card (#6458) imports 16 icons from lucide-react, which #6241 removed from the dependency tree in favour of the in-house @sim/emcn/icons set. next build fails on both files:

sim:build: Module not found: Can't resolve 'lucide-react'
  > 10 | import {
  > 11 |   ArrowLeftRight,
  ...
  > 26 | } from 'lucide-react'

Why nothing caught it

fumadocs-ui pulls lucide-react in for apps/docs, and the install hoists it into apps/sim/node_modules. So dev, tsc, biome, and editor autocomplete all resolve it — a phantom dependency. Only an install that excludes the docs app (the Docker build) sees it missing.

check-import-specifiers exists for exactly this "Module not found" class but skips bare npm specifiers by design ("node_modules' business, and flaky on install state"), so this fell through the gap. Worth a follow-up: validating bare specifiers against each workspace's declared deps would close it.

The fix

Two files, 16 icons. Eleven already existed in the house set under the same name.

Three map onto existing glyphs that are already the same drawing:

The remaining four are new: MessageSquareText, SkipForward, SlidersHorizontal, ToggleLeft.

How the four were ported

Same mechanical transform #6241 used, reverse-engineered from the icons it ported rather than eyeballed — lucide geometry scaled 0.86 and translated so lucide's (12, 12) centre lands on (10.25, 9.75) in a -1 -2 24 24 viewBox, stroked at the house 1.55. Confirmed exact against zap on all five vertices.

Every icon ported in #6241 measures to that centre (21 of 21 sampled, via getBBox() in a real browser). The four new ones measure there exactly, and their bboxes are exact 0.86 multiples of the lucide originals:

message-square-text    bbox  15.48 x  15.48   center ( 10.25,   9.75)
skip-forward           bbox  12.04 x  13.76   center ( 10.25,   9.75)
sliders-horizontal     bbox  15.48 x   17.2   center ( 10.25,   9.75)
toggle-left            bbox   17.2 x  12.04   center ( 10.25,   9.75)

Verified

• bun run type-check — apps/sim and packages/emcn clean
• biome check clean; check:bare-icons and check:icon-paths pass
• No lucide-react reference left in any source file
• Rendered all four at 56px against the existing set and at the real 14px meta-row size, light and dark

🤖 Generated with Claude Code