diff --git a/CHANGELOG.md b/CHANGELOG.md
index a2223e9a5..e7b033bc8 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,9 +4,12 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 
 ## Unreleased
 
+### Features
+- **forms:** add `.sf-live-validate` — an opt-in scope (apply to a `<form>`/`<fieldset>`) that restores native `:user-invalid`/`:user-valid` → `--sf-field-border-color` feedback within that subtree, gated behind a real submit attempt rather than firing unconditionally on simple focus+blur. The zero-JS convenience of the removed automatic behaviour, without its premature-feedback failure mode.
+
 ### Breaking Changes
 - **components:** `.sf-btn` nested in `.sf-card` no longer auto-shrinks its label to `--sf-text-s`. Buttons in cards now render at their own size like anywhere else; add `.sf-btn--s` for a compact card action. The orphaned `--sf-card-btn-font-size` token is removed. See `docs/migration.md`.
-- **forms:** form fields no longer auto-colour on native `:user-invalid` / `:user-valid` — a field no longer looks "broken" the instant the browser considers it invalid, before your app or the user submits anything. The explicit `.sf-is-invalid` / `.sf-is-valid` (and `.sf-is-warning` / `.sf-is-info` / `.sf-is-danger`) state classes are unaffected and remain the way to colour a field's validation state. See `docs/migration.md`.
+- **forms:** form fields no longer auto-colour on native `:user-invalid` / `:user-valid` — a field no longer looks "broken" the instant the browser considers it invalid, before your app or the user submits anything. The explicit `.sf-is-invalid` / `.sf-is-valid` (and `.sf-is-warning` / `.sf-is-info` / `.sf-is-danger`) state classes are unaffected and remain the way to colour a field's validation state; `.sf-live-validate` opts a `<form>` back into native-triggered feedback. See `docs/migration.md`.
 
 ## [0.7.15] - 2026-07-11
 
diff --git a/configurator/src/data/classes.generated.json b/configurator/src/data/classes.generated.json
index 3b8b70715..3e24e7a2a 100644
--- a/configurator/src/data/classes.generated.json
+++ b/configurator/src/data/classes.generated.json
@@ -2284,6 +2284,16 @@
       "optional": true,
       "layer": "slashed.utilities"
     },
+    {
+      "name": "sf-live-validate",
+      "selector": ".sf-live-validate",
+      "kind": "form",
+      "category": "Forms",
+      "group": "",
+      "description": "Scopes native constraint-validation feedback to this subtree: within it, :user-invalid/:user-valid on input/select/textarea drive --sf-field-border-color (the same token .sf-is-invalid/.sf-is-valid set explicitly). Apply to a <form> or <fieldset>. Off by default so a still-empty required field isn't marked invalid before a submit is attempted.",
+      "optional": true,
+      "layer": "slashed.forms"
+    },
     {
       "name": "sf-marker--action",
       "selector": ".sf-marker--action",
diff --git a/demos/full-api-demo-with-overrides.html b/demos/full-api-demo-with-overrides.html
index 6b5b3afc3..3cd9b3dd1 100644
--- a/demos/full-api-demo-with-overrides.html
+++ b/demos/full-api-demo-with-overrides.html
@@ -122,7 +122,7 @@
   </nav>
   <main id="main">
     <h1>SLASHED Full API Demo</h1>
-    <p style="color:var(--sf-color-text--muted)">v0.7.15 · full bundle from jsDelivr CDN · 328 classes · 755 tokens (265 configurable)</p>
+    <p style="color:var(--sf-color-text--muted)">v0.7.15 · full bundle from jsDelivr CDN · 329 classes · 755 tokens (265 configurable)</p>
     <div class="notice"><strong>ultimate-override.css is ACTIVE.</strong> Every value below is recomputed from perturbed knob tokens — toggle it off in the toolbar, or compare against <a href="full-api-demo.html">the un-overridden page</a>.</div>
 
     <section id="tokens">
diff --git a/demos/full-api-demo.html b/demos/full-api-demo.html
index 583e6553e..0b41d8e47 100644
--- a/demos/full-api-demo.html
+++ b/demos/full-api-demo.html
@@ -121,7 +121,7 @@
   </nav>
   <main id="main">
     <h1>SLASHED Full API Demo</h1>
-    <p style="color:var(--sf-color-text--muted)">v0.7.15 · full bundle from jsDelivr CDN · 328 classes · 755 tokens (265 configurable)</p>
+    <p style="color:var(--sf-color-text--muted)">v0.7.15 · full bundle from jsDelivr CDN · 329 classes · 755 tokens (265 configurable)</p>
     <div class="notice">Baseline render with default tokens. Use the toolbar to switch theme, toggle the ultimate override live, or replay motion. The always-on override variant is <a href="full-api-demo-with-overrides.html">full-api-demo-with-overrides.html</a>.</div>
 
     <section id="tokens">
diff --git a/docs/api-index.json b/docs/api-index.json
index 8c2e1aff4..889a84433 100644
--- a/docs/api-index.json
+++ b/docs/api-index.json
@@ -26,14 +26,14 @@
       "optimal"
     ],
     "counts": {
-      "total": 1084,
+      "total": 1085,
       "by_type": {
-        "class": 329,
+        "class": 330,
         "token": 755
       },
       "by_tier": {
         "INTERNAL": 1,
-        "PUBLIC": 1024,
+        "PUBLIC": 1025,
         "PUBLIC-ADVANCED": 59
       },
       "by_role": {
@@ -41,8 +41,8 @@
         "knob": 265
       },
       "tokens": 755,
-      "classes": 329,
-      "sf_classes": 292,
+      "classes": 330,
+      "sf_classes": 293,
       "is_classes": 28,
       "unprefixed_classes": 9,
       "by_category": {
@@ -50,6 +50,7 @@
         "Component tokens": 46,
         "Components": 30,
         "Core tokens": 622,
+        "Forms": 1,
         "Layout primitives": 145,
         "Layout tokens": 53,
         "Macro classes": 58,
@@ -24879,6 +24880,29 @@
         "full"
       ]
     },
+    {
+      "name": "sf-live-validate",
+      "type": "class",
+      "tier": "PUBLIC",
+      "selector": ".sf-live-validate",
+      "prefix": "sf",
+      "kind": "form",
+      "category": "Forms",
+      "area": "forms",
+      "group": "",
+      "description": "Scopes native constraint-validation feedback to this subtree: within it, :user-invalid/:user-valid on input/select/textarea drive --sf-field-border-color (the same token .sf-is-invalid/.sf-is-valid set explicitly). Apply to a <form> or <fieldset>. Off by default so a still-empty required field isn't marked invalid before a submit is attempted.",
+      "isVariant": false,
+      "baseClass": null,
+      "optional": true,
+      "layer": "slashed.forms",
+      "sourceFiles": [
+        "optional/forms.css"
+      ],
+      "bundles": [
+        "full",
+        "optimal"
+      ]
+    },
     {
       "name": "sf-marker--action",
       "type": "class",
diff --git a/docs/api-index.md b/docs/api-index.md
index f7824d951..1a1fde206 100644
--- a/docs/api-index.md
+++ b/docs/api-index.md
@@ -10,11 +10,11 @@ and a short description. The machine-readable companion (with all columns) is
 [registry.json](registry.json); for the tier contract see
 [architecture.md](architecture.md).
 
-**1084 elements** — 755 tokens, 329 classes.
+**1085 elements** — 755 tokens, 330 classes.
 
 | Tier | Count | Meaning |
 |---|---|---|
-| PUBLIC | 1024 | Everyday surface. SemVer-stable. |
+| PUBLIC | 1025 | Everyday surface. SemVer-stable. |
 | PUBLIC-ADVANCED | 59 | Same SemVer guarantee; niche/powerful. |
 | INTERNAL | 1 | Implementation detail; may change without a major bump. |
 
@@ -795,7 +795,7 @@ and a short description. The machine-readable companion (with all columns) is
 | `--sf-surface-bg-size` | PUBLIC | knob | surface | `cover` | background-size for the .sf-surface-bg image. Default: cover. |
 | `--sf-surface-color` | PUBLIC | consumption | surface | `var(--sf-color-base)` | Input for the generic .sf-surface macro. Set any color (including palette shades); the macro derives background, auto-contrast foreground, and the contextual token set from it. |
 
-## Classes (329)
+## Classes (330)
 
 ### Accessibility (8)
 
@@ -845,6 +845,12 @@ and a short description. The machine-readable companion (with all columns) is
 | `.sf-card--elevated` | PUBLIC | component | .sf-card | Floating card: hides the border, applies a larger shadow. |
 | `.sf-card--interactive` | PUBLIC | component | .sf-card | Adds a pointer cursor and a shadow/translate lift on hover or keyboard focus. Pair with .sf-clickable-parent for a fully clickable card. Lift is suppressed under prefers-reduced-motion. |
 
+### Forms (1)
+
+| Class | Tier | Kind | Group | Description |
+|---|---|---|---|---|
+| `.sf-live-validate` | PUBLIC | form | — | Scopes native constraint-validation feedback to this subtree: within it, :user-invalid/:user-valid on input/select/textarea drive --sf-field-border-color (the same token .sf-is-invalid/.sf-is-valid set explicitly). Apply to a <form> or <fieldset>. Off by default so a still-empty required field isn't marked invalid before a submit is attempted. |
+
 ### Layout primitives (145)
 
 | Class | Tier | Kind | Group | Description |
diff --git a/docs/classes.md b/docs/classes.md
index d4b7a4d15..a39eb2136 100644
--- a/docs/classes.md
+++ b/docs/classes.md
@@ -3,7 +3,7 @@
 > **Generated** from source by `scripts/gen-class-reference.js` —
 > run `npm run docs:classes` to refresh. Do not edit by hand.
 
-**292 .sf-classes, 28 .sf-is-classes.** Every `.sf-*` layout/macro class and `.sf-is-*` state class.
+**293 .sf-classes, 28 .sf-is-classes.** Every `.sf-*` layout/macro class and `.sf-is-*` state class.
 See [architecture.md](architecture.md) for layer order and naming conventions.
 
 ## Layout primitives (`core/layout.css`)
@@ -317,6 +317,14 @@ See [architecture.md](architecture.md) for layer order and naming conventions.
 | `.sf-theme-light` |
 | `.sf-theme-transition` |
 
+## Forms (`optional/forms.css`)
+
+1 classes.
+
+| Class |
+|---|
+| `.sf-live-validate` |
+
 ## Components (`optional/components.css`)
 
 32 classes.
diff --git a/docs/llm-guide.md b/docs/llm-guide.md
index 1cf8c678d..4759c7593 100644
--- a/docs/llm-guide.md
+++ b/docs/llm-guide.md
@@ -1091,10 +1091,18 @@ Used by `.sf-is-active`, `.sf-is-current`, etc. in `core/states.css`. Allow comp
 --sf-link-external-marker:  " ↗"              /* marker for .sf-link-external */
 
 /* Scoped override hooks — set per-field/form to override global borders/text */
---sf-field-border-color     /* set by validation states (error/success/warning/info/danger) */
+--sf-field-border-color     /* set by validation states (error/success/warning/info/danger); also set natively by :user-invalid/:user-valid within .sf-live-validate (opt-in — see below) */
 --sf-field-text-color       /* set by validation states for text color feedback */
 ```
 
+Native browser validation (`:user-invalid`/`:user-valid`) does NOT colour a field's
+border by default — add `.sf-live-validate` to the `<form>`/`<fieldset>` to opt a
+subtree into that feedback, gated behind a real submit attempt (not simple
+focus+blur, which would flag a still-empty required field prematurely). The
+explicit `.sf-is-invalid`/`.sf-is-valid` state classes (`core/states.css`) always
+win over `.sf-live-validate`'s native-triggered colour, regardless of specificity —
+`slashed.states` is declared after `slashed.forms` in the layer order (`core/layers.css`).
+
 Component tokens from `optional/tokens.components.css`:
 
 ```css
diff --git a/docs/migration.md b/docs/migration.md
index 5b179baef..c01f54720 100644
--- a/docs/migration.md
+++ b/docs/migration.md
@@ -93,6 +93,20 @@ The underlying `--sf-field-border-color` token and its consumers (resting
 border, focus, autofill) are unchanged — only the automatic pseudo-class
 trigger is gone.
 
+**Want the native-triggered feedback back, without writing JS?** Add
+`.sf-live-validate` to the `<form>` (or a `<fieldset>`) — it re-enables the
+`:user-invalid`/`:user-valid` → `--sf-field-border-color` pivot, scoped to that
+subtree, but only once a submit has actually been attempted (not on simple
+focus+blur, which is what made the original unconditional behaviour fire
+prematurely mid-form-fill):
+
+```html
+<form class="sf-live-validate">
+  <input type="email" required>
+  <button type="submit">Submit</button>
+</form>
+```
+
 ### `--sf-touch-target` decoupled from `--sf-size-l`; size scale regularised (breaking)
 
 `--sf-touch-target` used to be `var(--sf-size-l)`, which coupled the WCAG 2.5.5
diff --git a/docs/registry.json b/docs/registry.json
index 982b3f83a..0e65ba519 100644
--- a/docs/registry.json
+++ b/docs/registry.json
@@ -21,7 +21,7 @@
     ],
     "counts": {
       "tokens": 755,
-      "sf_classes": 292,
+      "sf_classes": 293,
       "is_classes": 28
     }
   },
@@ -978,6 +978,7 @@
     "sf-link--subtle",
     "sf-link-external",
     "sf-list-none",
+    "sf-live-validate",
     "sf-marker--action",
     "sf-marker--primary",
     "sf-marker--secondary",
diff --git a/docs/token-annotations.json b/docs/token-annotations.json
index d8c9081aa..63b3a2be5 100644
--- a/docs/token-annotations.json
+++ b/docs/token-annotations.json
@@ -1063,6 +1063,7 @@
     "sf-link--reverse": "Link color modifier: reverses the default link color to work on dark/inverted backgrounds. Sets color to --sf-color-text--inverse.",
     "sf-link--subtle": "Link color modifier: renders the link in the body text color instead of the default action color. Underline still indicates the link on hover.",
     "sf-link-external": "Automatically appends an external-link icon (via ::after content) to indicate the link opens in a new tab or goes to an external domain.",
+    "sf-live-validate": "Scopes native constraint-validation feedback to this subtree: within it, :user-invalid/:user-valid on input/select/textarea drive --sf-field-border-color (the same token .sf-is-invalid/.sf-is-valid set explicitly). Apply to a <form> or <fieldset>. Off by default so a still-empty required field isn't marked invalid before a submit is attempted.",
     "sf-no-tap-highlight": "Removes the mobile tap highlight color (-webkit-tap-highlight-color: transparent). Use on interactive elements with a custom active state.",
     "sf-not-prose": "Opt-out of sf-prose typography styles within a prose block. Apply to an element that should keep default browser or component styles.",
     "sf-overflow-fade": "Adds a gradient fade at the inline-end of an overflowing element to hint at hidden content. Use inside sf-reel or any scroll container.",
diff --git a/optional/forms.css b/optional/forms.css
index 91d972c02..05bd901dd 100644
--- a/optional/forms.css
+++ b/optional/forms.css
@@ -86,6 +86,34 @@
   }
   /* stylelint-enable selector-pseudo-class-no-unknown */
 
+  /* Opt-in native validation feedback. Unconditional :user-invalid/:user-valid
+     styling was removed in 0.8.0 (see docs/migration.md): it fires on simple
+     focus+blur, so a still-empty required field could be marked invalid mid
+     multi-field form-fill, before any submit was attempted — the pattern
+     Bootstrap's own .was-validated gate exists to avoid. .sf-live-validate is
+     that same gate: put it on a <form> or <fieldset> to scope the pivot to
+     that subtree, so it only lights up on a real submit attempt (or explicit
+     interaction) instead of applying everywhere by default.
+
+     Safe to combine with manual validation: .sf-is-invalid/.sf-is-valid
+     (core/states.css, @layer slashed.states) always win over the rules below
+     regardless of selector specificity, because slashed.states is declared
+     AFTER slashed.forms in the layer order (core/layers.css) — cascade layer
+     order beats specificity. A field you've manually marked .sf-is-invalid
+     (e.g. a server-side error) can't be silently un-coloured by these rules
+     even if the browser considers it natively valid. */
+  .sf-live-validate input:user-invalid,
+  .sf-live-validate select:user-invalid,
+  .sf-live-validate textarea:user-invalid {
+    --sf-field-border-color: var(--sf-color-danger);
+  }
+
+  .sf-live-validate input:user-valid,
+  .sf-live-validate select:user-valid,
+  .sf-live-validate textarea:user-valid {
+    --sf-field-border-color: var(--sf-color-success);
+  }
+
   /* Numeric inputs */
   input[type="number"] {
     font-variant-numeric: var(--sf-font-numeric, tabular-nums);
diff --git a/scripts/lib/api-index/extract.js b/scripts/lib/api-index/extract.js
index f48d8cf79..43c03c3f0 100644
--- a/scripts/lib/api-index/extract.js
+++ b/scripts/lib/api-index/extract.js
@@ -79,7 +79,7 @@ export const FILE_META = {
   'core/motion.css':            { category: 'Motion / animation',    area: 'motion',        kind: 'motion'        },
   'core/print.css':             { category: 'Print',                 area: 'print',         kind: 'print'         },
   'core/themes.css':            { category: 'Theme utilities',        area: 'theme',         kind: 'theme'         },
-  'optional/forms.css':         { category: 'Forms (classless)',     area: 'forms',         kind: 'form'          },
+  'optional/forms.css':         { category: 'Forms',                 area: 'forms',         kind: 'form'          },
   'optional/components.css':    { category: 'Components',             area: 'components',    kind: 'component'     },
   'optional/theme-example.css': { category: 'Theme example',         area: 'theme',         kind: 'theme'         },
   'optional/utilities.css':     { category: 'Utilities',             area: 'utilities',     kind: 'utility'       },
diff --git a/tests/forms.spec.js b/tests/forms.spec.js
index dfe1cde9f..4c12f89b9 100644
--- a/tests/forms.spec.js
+++ b/tests/forms.spec.js
@@ -67,6 +67,34 @@ for (const theme of ['light', 'dark']) {
       expect(cs['border-top-color']).toBe('rgb(1, 2, 3)');
     });
 
+    test('.sf-live-validate scopes native validation feedback to a submitted form', async ({ page }) => {
+      // Two forms, both with an invalid required field, both submitted (a real,
+      // trusted click — :user-invalid needs genuine interaction, not a bare JS
+      // focus()/blur() call, to match reliably). Only "validated" carries the
+      // opt-in class, so only its field should pick up --sf-field-border-color.
+      // The invalid-event listener suppresses the native validation bubble —
+      // the standard pairing for custom validation styling — so the assertion
+      // isn't confused by the browser's own transient bubble-UI rendering.
+      await mount(page, `
+        <form id="plain"><input type="email" id="plain-input" value="not-an-email" required><button type="submit">Go</button></form>
+        <form id="validated" class="sf-live-validate"><input type="email" id="validated-input" value="not-an-email" required><button type="submit">Go</button></form>
+        <script>
+          for (const id of ['plain-input', 'validated-input']) {
+            document.getElementById(id).addEventListener('invalid', (e) => e.preventDefault());
+          }
+        </script>
+      `);
+      await page.locator('#plain button[type=submit]').click();
+      await page.locator('#validated button[type=submit]').click();
+      const [plainVar, validatedVar, danger] = await page.evaluate(() => [
+        getComputedStyle(document.getElementById('plain-input')).getPropertyValue('--sf-field-border-color').trim(),
+        getComputedStyle(document.getElementById('validated-input')).getPropertyValue('--sf-field-border-color').trim(),
+        getComputedStyle(document.body).getPropertyValue('--sf-color-danger').trim(),
+      ]);
+      expect(plainVar).toBe('');            // unscoped: no auto-colouring, even on submit
+      expect(validatedVar).toBe(danger);    // scoped: native invalidity now drives the token
+    });
+
     test('textarea is vertically resizable with a minimum height', async ({ page }) => {
       await mount(page, `<textarea id="t"></textarea>`);
       const cs = await computed(page, ['resize', 'min-block-size']);