Minimum Width

How narrow is a component allowed to get? Silvery answers that with CSS's automatic minimum size (§4.5): a flex item does not shrink below its own content's intrinsic minimum. In practice that means a paragraph shrinks until its longest unbreakable word, and then stops.

You usually get this for free. This page is for the cases where you need to know the rule — and for the one prop that opts out of it.

The short version

A <Text wrap="wrap"> floors at its longest unbreakable token, not at its natural width.
That floor propagates up through wrapper Boxes automatically. You do not thread anything through a wrap chain.
A <Text> that cannot wrap (truncate, clip, false) floors at 1 cell — it declares it can always collapse to an ellipsis. It needs no help to fit.
minWidth={0} opts a subtree out of the floor entirely. Reach for it in exactly one situation, below.

The floor, and where it comes from

Min-content is "the narrowest this content can be without overflowing". For text it is the longest run of characters with no break opportunity inside it:

tsx

// The container is 12 cells. The word is 34 and cannot break.
<Box width={12} flexDirection="row">
  <Box>
    <Text wrap="wrap">supercalifragilisticexpialidocious</Text>
  </Box>
</Box>

The inner Box lays out 34 cells wide and overflows, rather than squeezing to 12 and shredding the word. That is the auto-min floor doing its job: overflow is visible and fixable, a mangled word is neither.

Wrap mode decides the floor, and the rules live in one place — intrinsicWidths in @silvery/ag-term/unicode:

Wrap mode	min-content	max-content
`"wrap"` (and other wrappable modes)	longest unbreakable segment between break opportunities	natural width
`"hard"`	1 cell — any character may break	natural width
`"truncate"` / `"clip"` / `false`	1 cell — collapses to an ellipsis	natural width

Break opportunities include whitespace and hyphens, and also the soft separators / \ . _ : — so .claude/skills/{claim,do}/SKILL.md reports the longest path segment as its floor, not the whole path.

It propagates — don't thread props

The floor established at a <Text> is the same floor several wrappers up. Nesting depth does not change it:

tsx

// All three of these produce the same floor.
<Text wrap="wrap">{token}</Text>
<Box><Text wrap="wrap">{token}</Text></Box>
<Box><Box><Box><Text wrap="wrap">{token}</Text></Box></Box></Box>

This is why the old flexShrink={1} minWidth={0} incantation threaded down every wrapper is no longer needed — see Prose for that history. Containers walk their children (summing on the main axis, taking the max on the cross axis) and add their own padding, border and gap.

`minWidth={0}` — the one escape hatch

Use it when the container is legitimately narrower than the longest unbreakable token and you would rather clip than overflow:

tsx

// Without minWidth={0}: the cell is 34 wide and overflows its 12-cell parent.
// With it: the cell is 12 and the long word is clipped by overflow="hidden".
<Box width={12} flexDirection="row">
  <Box minWidth={0} overflow="hidden">
    <Text wrap="wrap">supercalifragilisticexpialidocious</Text>
  </Box>
</Box>

It works on the <Text> itself too, via TextFlexItemProps.

When NOT to reach for it

Non-wrappable Text does not need it. A <Text wrap="truncate"> already reports min-content 1, so a Box around it shrinks to its container unaided; adding minWidth={0} measurably changes nothing. Guidance that still prescribes the hatch for truncate/clip Text predates a fix landed 2026-05-11 — before it, non-wrappable Text reported min-content equal to max-content, the parent got pinned at natural width, and its overflow="hidden" hard-clipped mid-word with no ellipsis because flex never shrank the Text.

Both claims in this section are pinned by contract tests in tests/features/min-width-protocol.test.tsx, so this page cannot quietly drift off the code.

Engine requirement

Recursive intrinsic min-content is a flexily-only capability. It rides on a measure mode (MEASURE_MODE_MIN_CONTENT) that Yoga does not define, so under SILVERY_ENGINE=yoga the adapter throws rather than silently substituting a different mode and producing a plausible wrong layout. The fix it names is SILVERY_ENGINE=flexily.

Container-side §4.5 (an overflow: hidden/scroll container gets min-size: auto = 0) and item-side auto-min are both implemented under the CSS preset; the Yoga preset keeps Yoga's looser min: undefined → 0.

Where the rest of this is written down

This page covers the silvery-visible surface. The engine mechanics — how the automatic minimum size is derived, how contentMinSize relates to baseSize, the specified-size suggestion cap, and the per-node caching — are documented once, in flexily's Yoga divergences guide under "Divergence 4: flex-item automatic minimum size". That is the canonical home for the algorithm; this page deliberately does not restate it.

Minimum Width ​

The short version ​

The floor, and where it comes from ​

It propagates — don't thread props ​

minWidth={0} — the one escape hatch ​

When NOT to reach for it ​

Engine requirement ​

Where the rest of this is written down ​

See also ​