diff --git a/.claude/skills/update-design-tokens/SKILL.md b/.claude/skills/update-design-tokens/SKILL.md
index 97803ecd..d2715f8b 100644
--- a/.claude/skills/update-design-tokens/SKILL.md
+++ b/.claude/skills/update-design-tokens/SKILL.md
@@ -34,28 +34,44 @@ covered below.
 | --- | --- |
 | source of truth | `tokens/{core,chat,video}/semantics/{light,dark}.json` upstream |
 | upstream Flutter build | `build/flutter/tokens/lib/src/{android,ios,web}/{light,dark}/stream_tokens.dart` |
-| vendored here | `packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/{light,dark}/stream_tokens.dart` |
+| colors vendored here | `lib/src/theme/primitives/internal/tokens/{light,dark}/stream_tokens.dart` |
+| dimensions vendored here | `lib/src/theme/primitives/internal/tokens/stream_tokens_dimensions.dart` (one copy — mode-independent) |
 | root semantics | `lib/src/theme/semantics/stream_color_scheme.dart` |
 | derived values | each component's `build` / defaults, reading `colorScheme.*` |
 
 The vendored files are **maintained by hand** — there is no sync command, and the
-upstream build output is not copied in verbatim. Only `stream_colors.dart` and
-`stream_color_scheme.dart` import them; no component theme or widget ever
-references `StreamTokens`. (`stream_color_swatch_helper.dart` generates shades in
-HCT from a seed and never reads a token — it is measured *against* the vendored
-values, not driven by them.)
-
-**Colors are byte-identical across the three upstream flavors; typography is not
-— and for type the flavor is `web`.** Only web carries the `Geist` family this
-package ships; android resolves to Roboto, iOS to SF Pro, and iOS also runs a
-size up at every step (`typographyFontSizeMd` is 17 there against 16 on
-android/web). So read colors from any flavor and type from `web`.
-
-Dimensions — spacing, radius, sizes, line heights, weights — are identical across
-all three, so no flavor choice arises. They do come from upstream, but
-`StreamSpacing`, `StreamRadius` and `StreamTokensTypography` hard-code the values
-instead of reading the vendored constants, so a dimension change upstream has to
-be applied to those classes by hand.
+upstream build output is not copied in verbatim. Their readers are only the
+primitive and semantic classes: `stream_colors.dart` and
+`stream_color_scheme.dart` for the colors, and `stream_spacing.dart`,
+`stream_radius.dart` and `stream_tokens_typography.dart` for the dimensions. No
+component theme or widget ever references `StreamTokens` directly — a component
+reads a `colorScheme` field or one of those classes.
+(`stream_color_swatch_helper.dart` is *not* a reader: it generates shades in HCT
+from a seed, and is measured against the vendored values rather than driven by
+them.)
+
+**Colors are byte-identical across the three upstream flavors, and so is every
+dimension except font size.** iOS runs a size up at almost every step
+(`typographyFontSizeMd` is 17 there against 16 on android and web), which is why
+that one group is vendored per flavor while the rest is not. Read colors from any
+flavor; read a font size from the flavor whose scale you are editing.
+
+The font *family* does not arise: this package never sets one for text, and ships
+no text font — only the generated `Stream Icons` face. Upstream's
+`typographyFontFamilySans` is therefore not vendored.
+
+Spacing, radius, line heights and font weights are identical across all three
+flavors, so no flavor choice arises for them. They live in
+`internal/tokens/stream_tokens_dimensions.dart`, one copy rather than one per
+mode, read by `StreamSpacing`, `StreamRadius`, `StreamLineHeight` and
+`StreamFontWeight`.
+
+**Font sizes are the exception**: iOS runs a size up at almost every step, so
+they mirror upstream's flavor split in
+`internal/tokens/{android,ios}/stream_tokens_font_size.dart` and feed
+`StreamFontSize.android` and `StreamFontSize.ios`. A size change has to be taken
+from the matching flavor — `check:tokens` enforces that both declare the same
+names, but it cannot tell you a value came from the wrong one.
 
 Only core and chat semantics are vendored into `internal/tokens/`; the video
 namespace is not. That is about *vendoring*, not about impact — a video token can
@@ -347,21 +363,34 @@ component from a token, which is the one thing a component must not do — a
 constant bypasses the seedable color scheme, so a custom brand or chrome stops
 applying.
 
-Dimensions and type are a separate matter. Their upstream values *are* mirrored
-here, but in `StreamSpacing`, `StreamRadius` and `StreamTokensTypography`, which
-hard-code them rather than reading a token constant. So a spacing or radius change
-is applied to those classes by hand — and taking the type values from the wrong
-flavor is a live mistake, since only `web` carries the `Geist` family.
-
-That hand-copying is the same hazard as baking a hex where a swatch belongs, one
-layer up: nothing ties the class to the constant it mirrors, so the two drift
-silently. The fix is to have those classes read the constants, not to add more
-unread ones.
+Spacing, radius and line heights live in `stream_tokens_dimensions.dart` instead
+— one mode-independent file, read by `StreamSpacing`, `StreamRadius` and
+`StreamLineHeight`. Edit the value there and the classes follow; do not
+re-introduce a literal in a class, which is the same hazard as baking a hex where
+a swatch belongs, one layer up.
+
+One upstream dimension is deliberately absent: **`radiusNone`**, since the
+analyzer's `use_named_constants` prefers `Radius.zero` over `circular(0)`. The
+font family is not carried either — this package never sets one for text, only
+for the emoji and icon fonts. Weights are carried as `FontWeight` rather than the
+raw 400/500/600/700, for the same reason the rest are `double`: it is the type
+Flutter consumes, and `FontWeight` has no public constructor from a number.
+
+**`melos run check:tokens` enforces all of this.** It fails when a constant in
+`internal/tokens/` is never referenced, and when `light/` and `dark/` disagree
+about which constants exist — the second because a field resolving from a constant
+in one mode but not the other falls back silently rather than failing. So there is
+no judgment call about what belongs: add a constant when a field or class will
+read it, and CI tells you if you got it wrong.
+
+Run it after any token edit, alongside `analyze`. Its allowlist is empty and worth
+keeping that way; an entry there is a token the SDK carries without using.
 
 ## After editing
 
 ```bash
 melos run analyze
+melos run check:tokens
 melos run test:flutter
 ```
 
diff --git a/.github/workflows/stream_core_flutter_workflow.yml b/.github/workflows/stream_core_flutter_workflow.yml
index 3f5a0c99..cb82e96e 100644
--- a/.github/workflows/stream_core_flutter_workflow.yml
+++ b/.github/workflows/stream_core_flutter_workflow.yml
@@ -53,9 +53,10 @@ jobs:
         run: |
           melos run analyze
 
-      - name: Check Barrels
+      - name: Check barrels and tokens
         run: |
           melos run check:barrels
+          melos run check:tokens
 
       - name: Check formatting
         run: |
diff --git a/CLAUDE.md b/CLAUDE.md
index 9eb04c0f..847985e7 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -114,16 +114,23 @@ Generated files have `.g.theme.dart` extension. After modifying `.theme.dart` fi
 Colors originate in [design-system-tokens](https://github.com/GetStream/design-system-tokens),
 the same repo the icons come from. `theme/primitives/internal/tokens/{light,dark}/stream_tokens.dart`
 holds the vendored values; it is maintained by hand, is not part of the public API,
-and only `stream_colors.dart` and `stream_color_scheme.dart` read it.
+and only `stream_colors.dart` and `stream_color_scheme.dart` read it. Dimensions
+live beside it in `internal/tokens/stream_tokens_dimensions.dart` — one
+mode-independent copy, read by `StreamSpacing`, `StreamRadius`,
+`StreamLineHeight` and `StreamFontWeight`. Font sizes are the one group that
+differs per platform, so they mirror upstream's flavor split in
+`internal/tokens/{android,ios}/stream_tokens_font_size.dart` and feed the two
+`StreamFontSize` scales.
 
 Only the **root semantics** are mapped to a `StreamColorScheme` field. Upstream's
 derived tokens (`badge/*`, `button/*`, `avatar/*`) get no field — components
-re-derive them from `colorScheme.*` in their own defaults. Typography, spacing and
-radius do come from upstream, but `StreamTokensTypography`, `StreamSpacing` and
-`StreamRadius` hard-code the values rather than reading a token constant, so a
-dimension change is applied to those classes by hand. `StreamColorScheme` is
+re-derive them from `colorScheme.*` in their own defaults. `StreamColorScheme` is
 exported from `core.dart`, so every field on it is public API.
 
+`melos run check:tokens` fails on a vendored constant nothing reads, and on
+`light/` and `dark/` disagreeing about which constants exist — so add a constant
+only when a field or class will read it, and let CI catch the rest.
+
 A field's dartdoc comes from the token's own `$description` in the upstream JSON —
 quote it rather than inventing prose, but resolve the aliases first, since a
 description tracks the token's own light/dark progression and not a comparison
diff --git a/melos.yaml b/melos.yaml
index d2dbc4d2..25104928 100644
--- a/melos.yaml
+++ b/melos.yaml
@@ -155,6 +155,14 @@ scripts:
     run: melos exec -c 1 --file-exists="check_barrels.yaml" -- "dart run \$MELOS_ROOT_PATH/scripts/check_barrels.dart"
     description: Validate the public-barrel contract for packages with a check_barrels.yaml config.
 
+  check:tokens:
+    # Deliberately not `melos exec`: any package filter that stops matching
+    # selects zero packages and reports SUCCESS, which is the one outcome this
+    # check must never produce silently. Run once from the root instead, and
+    # let the script fail if the package or its token directory is missing.
+    run: dart run scripts/check_tokens.dart
+    description: Fail if a vendored design token is unreferenced, or if light/ and dark/ disagree.
+
   generate:dart:
     run: melos exec -c 1 --depends-on="build_runner" --no-flutter -- "dart run build_runner build --delete-conflicting-outputs"
     description: Build all generated files for Dart packages in this project.
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/android/stream_tokens_font_size.dart b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/android/stream_tokens_font_size.dart
new file mode 100644
index 00000000..123d7f14
--- /dev/null
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/android/stream_tokens_font_size.dart
@@ -0,0 +1,20 @@
+/// Font-size tokens from the design system, android flavor.
+///
+/// The one dimension group that differs per platform: iOS runs a size up at
+/// almost every step, so the token repo publishes a separate set. Read through
+/// `StreamFontSize.android`, which is the public surface.
+///
+/// Declared as `double` because that is what `TextStyle` takes; the token repo
+/// emits them without a decimal point.
+class StreamTokensFontSize {
+  StreamTokensFontSize._();
+
+  static const double typographyFontSizeMicro = 8;
+  static const double typographyFontSizeXxs = 10;
+  static const double typographyFontSizeXs = 12;
+  static const double typographyFontSizeSm = 14;
+  static const double typographyFontSizeMd = 16;
+  static const double typographyFontSizeLg = 18;
+  static const double typographyFontSizeXl = 20;
+  static const double typographyFontSize2xl = 24;
+}
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/dark/stream_tokens.dart b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/dark/stream_tokens.dart
index 0a112977..a7764591 100644
--- a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/dark/stream_tokens.dart
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/dark/stream_tokens.dart
@@ -126,120 +126,6 @@ class StreamTokens {
   static const lime700 = Color(0xFF355315);
   static const lime800 = Color(0xFF203A00);
   static const lime900 = Color(0xFF112100);
-  static const size2 = 2;
-  static const size4 = 4;
-  static const size6 = 6;
-  static const size8 = 8;
-  static const size12 = 12;
-  static const size16 = 16;
-  static const size20 = 20;
-  static const size24 = 24;
-  static const size32 = 32;
-  static const size40 = 40;
-  static const size48 = 48;
-  static const size64 = 64;
-  static const size28 = 28;
-  static const size80 = 80;
-  static const size128 = 128;
-  static const size240 = 240;
-  static const size320 = 320;
-  static const size480 = 480;
-  static const size560 = 560;
-  static const size640 = 640;
-  static const size760 = 760;
-  static const size144 = 144;
-  static const size208 = 208;
-  static const size56 = 56;
-  static const radius0 = 0;
-  static const radius2 = 2;
-  static const radius4 = 4;
-  static const radius6 = 6;
-  static const radius8 = 8;
-  static const radius12 = 12;
-  static const radius16 = 16;
-  static const radius20 = 20;
-  static const radius24 = 24;
-  static const radius32 = 32;
-  static const radiusFull = 9999;
-  static const space0 = 0;
-  static const space2 = 2;
-  static const space4 = 4;
-  static const space8 = 8;
-  static const space12 = 12;
-  static const space16 = 16;
-  static const space20 = 20;
-  static const space24 = 24;
-  static const space32 = 32;
-  static const space40 = 40;
-  static const space48 = 48;
-  static const space64 = 64;
-  static const space80 = 80;
-  static const w100 = 1;
-  static const w150 = 1.5;
-  static const w200 = 2;
-  static const w300 = 3;
-  static const w400 = 4;
-  static const w120 = 1.2;
-  static const fontFamilyGeist = 'Geist';
-  static const fontFamilyGeistMono = 'Geist Mono';
-  static const fontFamilySfPro = 'SF Pro';
-  static const fontFamilySfMono = 'SF Mono';
-  static const fontFamilyRoboto = 'Roboto';
-  static const fontFamilyRobotoMono = 'Roboto Mono';
-  static const fontWeightW400 = 400;
-  static const fontWeightW500 = 500;
-  static const fontWeightW600 = 600;
-  static const fontWeightW700 = 700;
-  static const fontSizeSize8 = 8;
-  static const fontSizeSize10 = 10;
-  static const fontSizeSize11 = 11;
-  static const fontSizeSize12 = 12;
-  static const fontSizeSize13 = 13;
-  static const fontSizeSize14 = 14;
-  static const fontSizeSize16 = 16;
-  static const fontSizeSize15 = 15;
-  static const fontSizeSize17 = 17;
-  static const fontSizeSize18 = 18;
-  static const fontSizeSize20 = 20;
-  static const fontSizeSize22 = 22;
-  static const fontSizeSize24 = 24;
-  static const fontSizeSize28 = 28;
-  static const fontSizeSize32 = 32;
-  static const fontSizeSize40 = 40;
-  static const fontSizeSize48 = 48;
-  static const fontSizeSize64 = 64;
-  static const lineHeightLineHeight8 = 8;
-  static const lineHeightLineHeight10 = 10;
-  static const lineHeightLineHeight12 = 12;
-  static const lineHeightLineHeight13 = 13;
-  static const lineHeightLineHeight14 = 14;
-  static const lineHeightLineHeight15 = 15;
-  static const lineHeightLineHeight16 = 16;
-  static const lineHeightLineHeight17 = 17;
-  static const lineHeightLineHeight18 = 18;
-  static const lineHeightLineHeight20 = 20;
-  static const lineHeightLineHeight24 = 24;
-  static const lineHeightLineHeight28 = 28;
-  static const lineHeightLineHeight32 = 32;
-  static const lineHeightLineHeight40 = 40;
-  static const lineHeightLineHeight48 = 48;
-  static const typographyFontFamilySans = 'Geist';
-  static const typographyFontFamilyMono = 'Geist Mono';
-  static const typographyFontWeightRegular = 400;
-  static const typographyFontWeightMedium = 500;
-  static const typographyFontWeightSemiBold = 600;
-  static const typographyFontWeightBold = 700;
-  static const typographyFontSizeXxs = 10;
-  static const typographyFontSizeXs = 12;
-  static const typographyFontSizeSm = 14;
-  static const typographyFontSizeMd = 16;
-  static const typographyFontSizeLg = 18;
-  static const typographyFontSizeXl = 20;
-  static const typographyFontSize2xl = 24;
-  static const typographyFontSizeMicro = 8;
-  static const typographyLineHeightTight = 16;
-  static const typographyLineHeightNormal = 20;
-  static const typographyLineHeightRelaxed = 24;
   static final lightElevation1 = [
     const BoxShadow(
       color: Color.fromRGBO(0, 0, 0, 0.05),
@@ -360,72 +246,6 @@ class StreamTokens {
       offset: Offset(0, 20),
     ),
   ];
-  static const radiusNone = 0;
-  static const radiusXxs = 2;
-  static const radiusXs = 4;
-  static const radiusSm = 6;
-  static const radiusMd = 8;
-  static const radiusLg = 12;
-  static const radiusXl = 16;
-  static const radius2xl = 20;
-  static const radiusMax = 9999;
-  static const radius3xl = 24;
-  static const radius4xl = 32;
-  static const spacingNone = 0;
-  static const spacingXxs = 4;
-  static const spacingXs = 8;
-  static const spacingSm = 12;
-  static const spacingMd = 16;
-  static const spacingXl = 24;
-  static const spacing2xl = 32;
-  static const spacing3xl = 40;
-  static const spacingLg = 20;
-  static const spacingXxxs = 2;
-  static const deviceRadius = 8;
-  static const deviceSafeAreaBottom = 0;
-  static const deviceSafeAreaTop = 0;
-  static const messageBubbleRadiusGroupTop = 20;
-  static const messageBubbleRadiusGroupMiddle = 20;
-  static const messageBubbleRadiusGroupBottom = 20;
-  static const messageBubbleRadiusTail = 0;
-  static const messageBubbleRadiusAttachment = 12;
-  static const messageBubbleRadiusAttachmentInline = 8;
-  static const composerRadiusFixed = 24;
-  static const composerRadiusFloating = 24;
-  static const buttonRadiusLg = 9999;
-  static const buttonRadiusMd = 9999;
-  static const buttonRadiusSm = 9999;
-  static const buttonRadiusFull = 9999;
-  static const buttonVisualHeightSm = 32;
-  static const buttonVisualHeightMd = 40;
-  static const buttonVisualHeightLg = 48;
-  static const buttonVisualHeightXs = 24;
-  static const buttonHitTargetMinHeight = 48;
-  static const buttonHitTargetMinWidth = 48;
-  static const buttonPaddingYLg = 14;
-  static const buttonPaddingYMd = 10;
-  static const buttonPaddingYSm = 6;
-  static const buttonPaddingYXs = 4;
-  static const buttonPaddingXIconOnlyLg = 14;
-  static const buttonPaddingXIconOnlyMd = 10;
-  static const buttonPaddingXIconOnlySm = 6;
-  static const buttonPaddingXIconOnlyXs = 4;
-  static const buttonPaddingXWithLabelLg = 16;
-  static const buttonPaddingXWithLabelMd = 16;
-  static const buttonPaddingXWithLabelSm = 16;
-  static const buttonPaddingXWithLabelXs = 12;
-  static const iconSizeXs = 12;
-  static const iconSizeSm = 16;
-  static const iconSizeMd = 20;
-  static const iconSizeLg = 32;
-  static const iconStrokeSubtle = 1.2;
-  static const iconStrokeDefault = 1.5;
-  static const iconStrokeEmphasis = 2;
-  static const emojiSm = 16;
-  static const emojiMd = 24;
-  static const emojiLg = 32;
-  static const emojiXl = 48;
-  static const emoji2xl = 64;
   static const backgroundCoreHighlight = Color(0xFF5F1A05);
   static const backgroundCoreOverlayLight = Color(0xBF000000);
   static const backgroundCoreOverlayDark = Color(0x80000000);
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/ios/stream_tokens_font_size.dart b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/ios/stream_tokens_font_size.dart
new file mode 100644
index 00000000..5db97270
--- /dev/null
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/ios/stream_tokens_font_size.dart
@@ -0,0 +1,20 @@
+/// Font-size tokens from the design system, ios flavor.
+///
+/// The one dimension group that differs per platform: iOS runs a size up at
+/// almost every step, so the token repo publishes a separate set. Read through
+/// `StreamFontSize.ios`, which is the public surface.
+///
+/// Declared as `double` because that is what `TextStyle` takes; the token repo
+/// emits them without a decimal point.
+class StreamTokensFontSize {
+  StreamTokensFontSize._();
+
+  static const double typographyFontSizeMicro = 8;
+  static const double typographyFontSizeXxs = 12;
+  static const double typographyFontSizeXs = 13;
+  static const double typographyFontSizeSm = 15;
+  static const double typographyFontSizeMd = 17;
+  static const double typographyFontSizeLg = 20;
+  static const double typographyFontSizeXl = 22;
+  static const double typographyFontSize2xl = 24;
+}
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/light/stream_tokens.dart b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/light/stream_tokens.dart
index 32d4b2cf..01f1c370 100644
--- a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/light/stream_tokens.dart
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/light/stream_tokens.dart
@@ -126,120 +126,6 @@ class StreamTokens {
   static const lime700 = Color(0xFF355315);
   static const lime800 = Color(0xFF203A00);
   static const lime900 = Color(0xFF112100);
-  static const size2 = 2;
-  static const size4 = 4;
-  static const size6 = 6;
-  static const size8 = 8;
-  static const size12 = 12;
-  static const size16 = 16;
-  static const size20 = 20;
-  static const size24 = 24;
-  static const size32 = 32;
-  static const size40 = 40;
-  static const size48 = 48;
-  static const size64 = 64;
-  static const size28 = 28;
-  static const size80 = 80;
-  static const size128 = 128;
-  static const size240 = 240;
-  static const size320 = 320;
-  static const size480 = 480;
-  static const size560 = 560;
-  static const size640 = 640;
-  static const size760 = 760;
-  static const size144 = 144;
-  static const size208 = 208;
-  static const size56 = 56;
-  static const radius0 = 0;
-  static const radius2 = 2;
-  static const radius4 = 4;
-  static const radius6 = 6;
-  static const radius8 = 8;
-  static const radius12 = 12;
-  static const radius16 = 16;
-  static const radius20 = 20;
-  static const radius24 = 24;
-  static const radius32 = 32;
-  static const radiusFull = 9999;
-  static const space0 = 0;
-  static const space2 = 2;
-  static const space4 = 4;
-  static const space8 = 8;
-  static const space12 = 12;
-  static const space16 = 16;
-  static const space20 = 20;
-  static const space24 = 24;
-  static const space32 = 32;
-  static const space40 = 40;
-  static const space48 = 48;
-  static const space64 = 64;
-  static const space80 = 80;
-  static const w100 = 1;
-  static const w150 = 1.5;
-  static const w200 = 2;
-  static const w300 = 3;
-  static const w400 = 4;
-  static const w120 = 1.2;
-  static const fontFamilyGeist = 'Geist';
-  static const fontFamilyGeistMono = 'Geist Mono';
-  static const fontFamilySfPro = 'SF Pro';
-  static const fontFamilySfMono = 'SF Mono';
-  static const fontFamilyRoboto = 'Roboto';
-  static const fontFamilyRobotoMono = 'Roboto Mono';
-  static const fontWeightW400 = 400;
-  static const fontWeightW500 = 500;
-  static const fontWeightW600 = 600;
-  static const fontWeightW700 = 700;
-  static const fontSizeSize8 = 8;
-  static const fontSizeSize10 = 10;
-  static const fontSizeSize11 = 11;
-  static const fontSizeSize12 = 12;
-  static const fontSizeSize13 = 13;
-  static const fontSizeSize14 = 14;
-  static const fontSizeSize16 = 16;
-  static const fontSizeSize15 = 15;
-  static const fontSizeSize17 = 17;
-  static const fontSizeSize18 = 18;
-  static const fontSizeSize20 = 20;
-  static const fontSizeSize22 = 22;
-  static const fontSizeSize24 = 24;
-  static const fontSizeSize28 = 28;
-  static const fontSizeSize32 = 32;
-  static const fontSizeSize40 = 40;
-  static const fontSizeSize48 = 48;
-  static const fontSizeSize64 = 64;
-  static const lineHeightLineHeight8 = 8;
-  static const lineHeightLineHeight10 = 10;
-  static const lineHeightLineHeight12 = 12;
-  static const lineHeightLineHeight13 = 13;
-  static const lineHeightLineHeight14 = 14;
-  static const lineHeightLineHeight15 = 15;
-  static const lineHeightLineHeight16 = 16;
-  static const lineHeightLineHeight17 = 17;
-  static const lineHeightLineHeight18 = 18;
-  static const lineHeightLineHeight20 = 20;
-  static const lineHeightLineHeight24 = 24;
-  static const lineHeightLineHeight28 = 28;
-  static const lineHeightLineHeight32 = 32;
-  static const lineHeightLineHeight40 = 40;
-  static const lineHeightLineHeight48 = 48;
-  static const typographyFontFamilySans = 'Geist';
-  static const typographyFontFamilyMono = 'Geist Mono';
-  static const typographyFontWeightRegular = 400;
-  static const typographyFontWeightMedium = 500;
-  static const typographyFontWeightSemiBold = 600;
-  static const typographyFontWeightBold = 700;
-  static const typographyFontSizeXxs = 10;
-  static const typographyFontSizeXs = 12;
-  static const typographyFontSizeSm = 14;
-  static const typographyFontSizeMd = 16;
-  static const typographyFontSizeLg = 18;
-  static const typographyFontSizeXl = 20;
-  static const typographyFontSize2xl = 24;
-  static const typographyFontSizeMicro = 8;
-  static const typographyLineHeightTight = 16;
-  static const typographyLineHeightNormal = 20;
-  static const typographyLineHeightRelaxed = 24;
   static final lightElevation1 = [
     const BoxShadow(
       color: Color.fromRGBO(0, 0, 0, 0.05),
@@ -360,72 +246,6 @@ class StreamTokens {
       offset: Offset(0, 20),
     ),
   ];
-  static const radiusNone = 0;
-  static const radiusXxs = 2;
-  static const radiusXs = 4;
-  static const radiusSm = 6;
-  static const radiusMd = 8;
-  static const radiusLg = 12;
-  static const radiusXl = 16;
-  static const radius2xl = 20;
-  static const radiusMax = 9999;
-  static const radius3xl = 24;
-  static const radius4xl = 32;
-  static const spacingNone = 0;
-  static const spacingXxs = 4;
-  static const spacingXs = 8;
-  static const spacingSm = 12;
-  static const spacingMd = 16;
-  static const spacingXl = 24;
-  static const spacing2xl = 32;
-  static const spacing3xl = 40;
-  static const spacingLg = 20;
-  static const spacingXxxs = 2;
-  static const deviceRadius = 8;
-  static const deviceSafeAreaBottom = 0;
-  static const deviceSafeAreaTop = 0;
-  static const messageBubbleRadiusGroupTop = 20;
-  static const messageBubbleRadiusGroupMiddle = 20;
-  static const messageBubbleRadiusGroupBottom = 20;
-  static const messageBubbleRadiusTail = 0;
-  static const messageBubbleRadiusAttachment = 12;
-  static const messageBubbleRadiusAttachmentInline = 8;
-  static const composerRadiusFixed = 24;
-  static const composerRadiusFloating = 24;
-  static const buttonRadiusLg = 9999;
-  static const buttonRadiusMd = 9999;
-  static const buttonRadiusSm = 9999;
-  static const buttonRadiusFull = 9999;
-  static const buttonVisualHeightSm = 32;
-  static const buttonVisualHeightMd = 40;
-  static const buttonVisualHeightLg = 48;
-  static const buttonVisualHeightXs = 24;
-  static const buttonHitTargetMinHeight = 48;
-  static const buttonHitTargetMinWidth = 48;
-  static const buttonPaddingYLg = 14;
-  static const buttonPaddingYMd = 10;
-  static const buttonPaddingYSm = 6;
-  static const buttonPaddingYXs = 4;
-  static const buttonPaddingXIconOnlyLg = 14;
-  static const buttonPaddingXIconOnlyMd = 10;
-  static const buttonPaddingXIconOnlySm = 6;
-  static const buttonPaddingXIconOnlyXs = 4;
-  static const buttonPaddingXWithLabelLg = 16;
-  static const buttonPaddingXWithLabelMd = 16;
-  static const buttonPaddingXWithLabelSm = 16;
-  static const buttonPaddingXWithLabelXs = 12;
-  static const iconSizeXs = 12;
-  static const iconSizeSm = 16;
-  static const iconSizeMd = 20;
-  static const iconSizeLg = 32;
-  static const iconStrokeSubtle = 1.2;
-  static const iconStrokeDefault = 1.5;
-  static const iconStrokeEmphasis = 2;
-  static const emojiSm = 16;
-  static const emojiMd = 24;
-  static const emojiLg = 32;
-  static const emojiXl = 48;
-  static const emoji2xl = 64;
   static const backgroundCoreHighlight = Color(0xFFFEF9DA);
   static const backgroundCoreOverlayLight = Color(0xBFFFFFFF);
   static const backgroundCoreOverlayDark = Color(0x401A1B25);
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/stream_tokens_dimensions.dart b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/stream_tokens_dimensions.dart
new file mode 100644
index 00000000..328d95db
--- /dev/null
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/stream_tokens_dimensions.dart
@@ -0,0 +1,66 @@
+import 'dart:ui';
+
+/// Dimension tokens from the design system.
+///
+/// Mode-independent, unlike the colors: the token repo publishes one set of
+/// spacing, radius, line-height and weight values, so these live here rather
+/// than being duplicated under `light/` and `dark/`. They are also identical
+/// across the android, ios and web flavors of the token build, so no flavor
+/// choice arises. Font sizes are the exception and live in `android/` and
+/// `ios/` beside this file.
+///
+/// Declared in the types Flutter consumes rather than the raw numbers upstream
+/// emits — `double` for what `Radius`, `EdgeInsets` and `TextStyle` take, and
+/// `FontWeight` for the weights, which have no public constructor from a number
+/// and so could not otherwise be read in a const expression.
+///
+/// Read these through `StreamSpacing`, `StreamRadius`, `StreamLineHeight` and
+/// `StreamFontWeight`, which are the public surface.
+///
+/// One upstream dimension is deliberately not carried: `radiusNone`, since the
+/// analyzer's `use_named_constants` prefers `Radius.zero` over `circular(0)`.
+/// The font family is not carried either — this package never sets one for
+/// text, only for the emoji and icon fonts.
+class StreamTokensDimensions {
+  StreamTokensDimensions._();
+
+  // Spacing
+  static const double spacingNone = 0;
+  static const double spacingXxxs = 2;
+  static const double spacingXxs = 4;
+  static const double spacingXs = 8;
+  static const double spacingSm = 12;
+  static const double spacingMd = 16;
+  static const double spacingLg = 20;
+  static const double spacingXl = 24;
+  static const double spacing2xl = 32;
+  static const double spacing3xl = 40;
+
+  // Radius
+  static const double radiusXxs = 2;
+  static const double radiusXs = 4;
+  static const double radiusSm = 6;
+  static const double radiusMd = 8;
+  static const double radiusLg = 12;
+  static const double radiusXl = 16;
+  static const double radius2xl = 20;
+  static const double radius3xl = 24;
+  static const double radius4xl = 32;
+  static const double radiusMax = 9999;
+
+  // Typography
+  static const double typographyLineHeightTight = 16;
+  static const double typographyLineHeightNormal = 20;
+  static const double typographyLineHeightRelaxed = 24;
+
+  // Typography — weight
+  //
+  // Declared as `FontWeight` rather than the raw 400/500/600/700 upstream
+  // emits, for the same reason the values above are `double`: it is the type
+  // Flutter consumes, and `FontWeight` has no public constructor taking a
+  // number, so an int here could not be read in a const expression.
+  static const FontWeight typographyFontWeightRegular = FontWeight.w400;
+  static const FontWeight typographyFontWeightMedium = FontWeight.w500;
+  static const FontWeight typographyFontWeightSemiBold = FontWeight.w600;
+  static const FontWeight typographyFontWeightBold = FontWeight.w700;
+}
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/stream_tokens_typography.dart b/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/stream_tokens_typography.dart
deleted file mode 100644
index 39e9b913..00000000
--- a/packages/stream_core_flutter/lib/src/theme/primitives/internal/tokens/stream_tokens_typography.dart
+++ /dev/null
@@ -1,122 +0,0 @@
-import 'package:flutter/widgets.dart';
-
-class StreamTokensTypography {
-  StreamTokensTypography._();
-
-  static const headingLg = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 20,
-    fontWeight: FontWeight.w600,
-    height: 1.2,
-  );
-  static const headingMd = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 18,
-    fontWeight: FontWeight.w600,
-    height: 1.1111111111111112,
-  );
-  static const headingSm = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 16,
-    fontWeight: FontWeight.w600,
-    height: 1.25,
-  );
-  static const headingXs = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 12,
-    fontWeight: FontWeight.w600,
-    height: 1.3333333333333333,
-  );
-  static const bodyDefault = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 16,
-    fontWeight: FontWeight.w400,
-    height: 1.25,
-  );
-  static const bodyEmphasis = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 16,
-    fontWeight: FontWeight.w600,
-    height: 1.25,
-  );
-  static const bodyLink = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 16,
-    fontWeight: FontWeight.w400,
-    height: 1.25,
-  );
-  static const bodyLinkEmphasis = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 16,
-    fontWeight: FontWeight.w600,
-    height: 1.25,
-  );
-  static const captionDefault = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 14,
-    fontWeight: FontWeight.w400,
-    height: 1.1428571428571428,
-  );
-  static const captionEmphasis = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 14,
-    fontWeight: FontWeight.w600,
-    height: 1.1428571428571428,
-  );
-  static const captionLink = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 14,
-    fontWeight: FontWeight.w400,
-    height: 1.1428571428571428,
-  );
-  static const captionLinkEmphasis = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 14,
-    fontWeight: FontWeight.w600,
-    height: 1.1428571428571428,
-  );
-  static const metadataDefault = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 12,
-    fontWeight: FontWeight.w400,
-    height: 1.3333333333333333,
-  );
-  static const metadataEmphasis = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 12,
-    fontWeight: FontWeight.w600,
-    height: 1.3333333333333333,
-  );
-  static const metadataLink = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 12,
-    fontWeight: FontWeight.w400,
-    height: 1.3333333333333333,
-  );
-  static const metadataLinkEmphasis = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 12,
-    fontWeight: FontWeight.w600,
-    height: 1.3333333333333333,
-  );
-  static const numericXl = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 14,
-    fontWeight: FontWeight.w700,
-  );
-  static const numericLg = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 12,
-    fontWeight: FontWeight.w700,
-  );
-  static const numericMd = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 10,
-    fontWeight: FontWeight.w700,
-  );
-  static const numericSm = TextStyle(
-    fontFamily: 'Geist',
-    fontSize: 8,
-    fontWeight: FontWeight.w700,
-  );
-}
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/stream_radius.dart b/packages/stream_core_flutter/lib/src/theme/primitives/stream_radius.dart
index ab8097f7..7067e619 100644
--- a/packages/stream_core_flutter/lib/src/theme/primitives/stream_radius.dart
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/stream_radius.dart
@@ -3,6 +3,8 @@ import 'dart:ui';
 import 'package:flutter/foundation.dart';
 import 'package:theme_extensions_builder_annotation/theme_extensions_builder_annotation.dart';
 
+import 'internal/tokens/stream_tokens_dimensions.dart' as tokens;
+
 part 'stream_radius.g.theme.dart';
 
 /// Border radius primitives for the Stream design system.
@@ -28,17 +30,20 @@ part 'stream_radius.g.theme.dart';
 class StreamRadius with _$StreamRadius {
   /// Creates a [StreamRadius] with the default values.
   const StreamRadius({
+    // `Radius.zero` rather than `circular(radiusNone)`: the analyzer's
+    // use_named_constants prefers the named constant, so the token has no
+    // reader and is not carried.
     this.none = .zero,
-    this.xxs = const .circular(2),
-    this.xs = const .circular(4),
-    this.sm = const .circular(6),
-    this.md = const .circular(8),
-    this.lg = const .circular(12),
-    this.xl = const .circular(16),
-    this.xxl = const .circular(20),
-    this.xxxl = const .circular(24),
-    this.xxxxl = const .circular(32),
-    this.max = const .circular(9999),
+    this.xxs = const .circular(tokens.StreamTokensDimensions.radiusXxs),
+    this.xs = const .circular(tokens.StreamTokensDimensions.radiusXs),
+    this.sm = const .circular(tokens.StreamTokensDimensions.radiusSm),
+    this.md = const .circular(tokens.StreamTokensDimensions.radiusMd),
+    this.lg = const .circular(tokens.StreamTokensDimensions.radiusLg),
+    this.xl = const .circular(tokens.StreamTokensDimensions.radiusXl),
+    this.xxl = const .circular(tokens.StreamTokensDimensions.radius2xl),
+    this.xxxl = const .circular(tokens.StreamTokensDimensions.radius3xl),
+    this.xxxxl = const .circular(tokens.StreamTokensDimensions.radius4xl),
+    this.max = const .circular(tokens.StreamTokensDimensions.radiusMax),
   });
 
   /// No border radius.
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/stream_spacing.dart b/packages/stream_core_flutter/lib/src/theme/primitives/stream_spacing.dart
index b56d5a3c..82928722 100644
--- a/packages/stream_core_flutter/lib/src/theme/primitives/stream_spacing.dart
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/stream_spacing.dart
@@ -1,6 +1,8 @@
 import 'package:flutter/foundation.dart';
 import 'package:theme_extensions_builder_annotation/theme_extensions_builder_annotation.dart';
 
+import 'internal/tokens/stream_tokens_dimensions.dart' as tokens;
+
 part 'stream_spacing.g.theme.dart';
 
 /// Spacing primitives for the Stream design system.
@@ -28,16 +30,16 @@ part 'stream_spacing.g.theme.dart';
 class StreamSpacing with _$StreamSpacing {
   /// Creates a [StreamSpacing] with the default values.
   const StreamSpacing({
-    this.none = 0,
-    this.xxxs = 2,
-    this.xxs = 4,
-    this.xs = 8,
-    this.sm = 12,
-    this.md = 16,
-    this.lg = 20,
-    this.xl = 24,
-    this.xxl = 32,
-    this.xxxl = 40,
+    this.none = tokens.StreamTokensDimensions.spacingNone,
+    this.xxxs = tokens.StreamTokensDimensions.spacingXxxs,
+    this.xxs = tokens.StreamTokensDimensions.spacingXxs,
+    this.xs = tokens.StreamTokensDimensions.spacingXs,
+    this.sm = tokens.StreamTokensDimensions.spacingSm,
+    this.md = tokens.StreamTokensDimensions.spacingMd,
+    this.lg = tokens.StreamTokensDimensions.spacingLg,
+    this.xl = tokens.StreamTokensDimensions.spacingXl,
+    this.xxl = tokens.StreamTokensDimensions.spacing2xl,
+    this.xxxl = tokens.StreamTokensDimensions.spacing3xl,
   });
 
   /// No spacing.
diff --git a/packages/stream_core_flutter/lib/src/theme/primitives/stream_typography.dart b/packages/stream_core_flutter/lib/src/theme/primitives/stream_typography.dart
index 098424c2..1cc544c3 100644
--- a/packages/stream_core_flutter/lib/src/theme/primitives/stream_typography.dart
+++ b/packages/stream_core_flutter/lib/src/theme/primitives/stream_typography.dart
@@ -3,6 +3,10 @@ import 'dart:ui';
 import 'package:flutter/foundation.dart';
 import 'package:theme_extensions_builder_annotation/theme_extensions_builder_annotation.dart';
 
+import 'internal/tokens/android/stream_tokens_font_size.dart' as android_tokens;
+import 'internal/tokens/ios/stream_tokens_font_size.dart' as ios_tokens;
+import 'internal/tokens/stream_tokens_dimensions.dart' as tokens;
+
 part 'stream_typography.g.theme.dart';
 
 /// Typography primitives for the Stream design system.
@@ -79,9 +83,9 @@ class StreamTypography with _$StreamTypography {
 class StreamLineHeight with _$StreamLineHeight {
   /// Creates a [StreamLineHeight] with the given values.
   const StreamLineHeight({
-    this.tight = 16,
-    this.normal = 20,
-    this.relaxed = 24,
+    this.tight = tokens.StreamTokensDimensions.typographyLineHeightTight,
+    this.normal = tokens.StreamTokensDimensions.typographyLineHeightNormal,
+    this.relaxed = tokens.StreamTokensDimensions.typographyLineHeightRelaxed,
   });
 
   /// The tight line height.
@@ -172,28 +176,28 @@ class StreamFontSize with _$StreamFontSize {
   ///
   /// Uses San Francisco font sizing conventions.
   static const StreamFontSize ios = .raw(
-    micro: 8,
-    xxs: 12,
-    xs: 13,
-    sm: 15,
-    md: 17,
-    lg: 20,
-    xl: 22,
-    xxl: 24,
+    micro: ios_tokens.StreamTokensFontSize.typographyFontSizeMicro,
+    xxs: ios_tokens.StreamTokensFontSize.typographyFontSizeXxs,
+    xs: ios_tokens.StreamTokensFontSize.typographyFontSizeXs,
+    sm: ios_tokens.StreamTokensFontSize.typographyFontSizeSm,
+    md: ios_tokens.StreamTokensFontSize.typographyFontSizeMd,
+    lg: ios_tokens.StreamTokensFontSize.typographyFontSizeLg,
+    xl: ios_tokens.StreamTokensFontSize.typographyFontSizeXl,
+    xxl: ios_tokens.StreamTokensFontSize.typographyFontSize2xl,
   );
 
   /// The Android font size scale.
   ///
   /// Uses Roboto font sizing conventions.
   static const StreamFontSize android = .raw(
-    micro: 8,
-    xxs: 10,
-    xs: 12,
-    sm: 14,
-    md: 16,
-    lg: 18,
-    xl: 20,
-    xxl: 24,
+    micro: android_tokens.StreamTokensFontSize.typographyFontSizeMicro,
+    xxs: android_tokens.StreamTokensFontSize.typographyFontSizeXxs,
+    xs: android_tokens.StreamTokensFontSize.typographyFontSizeXs,
+    sm: android_tokens.StreamTokensFontSize.typographyFontSizeSm,
+    md: android_tokens.StreamTokensFontSize.typographyFontSizeMd,
+    lg: android_tokens.StreamTokensFontSize.typographyFontSizeLg,
+    xl: android_tokens.StreamTokensFontSize.typographyFontSizeXl,
+    xxl: android_tokens.StreamTokensFontSize.typographyFontSize2xl,
   );
 
   /// The micro font size.
@@ -236,10 +240,10 @@ class StreamFontSize with _$StreamFontSize {
 class StreamFontWeight with _$StreamFontWeight {
   /// Creates a [StreamFontWeight] with the given values.
   const StreamFontWeight({
-    this.regular = .w400,
-    this.medium = .w500,
-    this.semibold = .w600,
-    this.bold = .w700,
+    this.regular = tokens.StreamTokensDimensions.typographyFontWeightRegular,
+    this.medium = tokens.StreamTokensDimensions.typographyFontWeightMedium,
+    this.semibold = tokens.StreamTokensDimensions.typographyFontWeightSemiBold,
+    this.bold = tokens.StreamTokensDimensions.typographyFontWeightBold,
   });
 
   /// The regular font weight.
diff --git a/scripts/check_tokens.dart b/scripts/check_tokens.dart
new file mode 100644
index 00000000..5b453d09
--- /dev/null
+++ b/scripts/check_tokens.dart
@@ -0,0 +1,392 @@
+// Verifies the vendored design-token files carry nothing dead.
+//
+// `lib/src/theme/primitives/internal/tokens/{light,dark}/stream_tokens.dart`
+// mirror a fraction of what the design-token repo publishes, by design: only
+// the root semantics live there, and a component's values are re-derived from
+// those in its own defaults. Nothing enforced that, so the files had grown to
+// 502 constants of which 163 were read — two thirds dead weight, and every
+// unread constant an invitation to reach for a token where a `colorScheme`
+// field was meant.
+//
+// This check fails when a constant is declared and never referenced, and when
+// the light and dark files disagree about which constants exist. It covers the
+// mode-independent dimension tokens next to them on the same terms.
+//
+// Every "nothing to check" path is a failure rather than a pass. A guard that
+// exits 0 because it found nothing to inspect is worse than no guard: it prints
+// the same tick as a real pass. So the package, the token directory, each
+// per-mode file and the dimensions file must all exist, each must yield a
+// plausible number of declarations, and the reference scan must actually open
+// files.
+//
+// Run with `melos run check:tokens`.
+import 'dart:io';
+
+import 'package:path/path.dart' as p;
+
+/// Names that are allowed to be unreferenced.
+///
+/// Empty, and worth keeping that way — an entry here is a token the SDK
+/// carries without using. Prefer deleting the constant and re-adding it when a
+/// component needs it, since the design-token repo remains the source of truth
+/// either way.
+///
+/// An entry matching no declaration is itself a failure, so this cannot rot
+/// into a list of names nobody can account for.
+const _allowedUnused = <String>{};
+
+const _packageName = 'stream_core_flutter';
+const _tokenDir = 'lib/src/theme/primitives/internal/tokens';
+
+/// Lower bound on the color constants each mode file must declare.
+///
+/// Guards against a parse that silently yields nothing — a reformat, a switch
+/// to `static final`, a move to generated code. Deliberately far below the real
+/// count (163 when this was written) so ordinary pruning never trips it.
+const _minColorTokens = 50;
+
+/// Lower bound on the dimension constants, on the same reasoning.
+const _minDimensionTokens = 10;
+
+/// Lower bound on the per-flavor font-size constants, on the same reasoning.
+const _minFontSizeTokens = 5;
+
+void main(List<String> args) {
+  // Resolved from the repo root rather than inherited from the caller's cwd,
+  // so the check cannot be pointed at a package that has no tokens and pass.
+  final packageRoot = args.isNotEmpty ? args.first : p.join(Directory.current.path, 'packages', _packageName);
+  if (!Directory(packageRoot).existsSync()) {
+    _fail(
+      'Missing ${p.relative(packageRoot, from: Directory.current.path)}.\n'
+      '  Run this from the repo root with `melos run check:tokens`, or pass\n'
+      '  the package root as the first argument.',
+    );
+  }
+
+  final tokenDir = Directory(p.join(packageRoot, _tokenDir));
+  if (!tokenDir.existsSync()) {
+    _fail(
+      'Missing $_tokenDir.\n'
+      '  If the vendored tokens moved, update _tokenDir here — do not let the\n'
+      '  check quietly pass on a directory that is not there.',
+    );
+  }
+
+  final libDir = Directory(p.join(packageRoot, 'lib'));
+  if (!libDir.existsSync()) _fail('Missing lib/ in $_packageName.');
+
+  final failures = <String>[];
+
+  final declared = <String, Set<String>>{};
+  for (final mode in const ['light', 'dark']) {
+    final file = File(p.join(tokenDir.path, mode, 'stream_tokens.dart'));
+    final label = p.relative(file.path, from: packageRoot);
+    if (!file.existsSync()) _fail('Missing $label');
+    declared[mode] = _declarations(file.readAsStringSync(), label);
+    if (declared[mode]!.length < _minColorTokens) {
+      _fail(
+        'Only ${declared[mode]!.length} constants parsed from $label, expected at least $_minColorTokens.\n'
+        '  Either the file shrank drastically or the declaration pattern no\n'
+        '  longer matches it. Both mean this check has stopped checking.',
+      );
+    }
+  }
+
+  // Both modes must declare the same names — a field that resolves from a
+  // constant in one mode and not the other silently falls back.
+  final onlyLight = declared['light']!.difference(declared['dark']!);
+  final onlyDark = declared['dark']!.difference(declared['light']!);
+  if (onlyLight.isNotEmpty || onlyDark.isNotEmpty) {
+    failures.add(
+      'light/ and dark/ declare different constants.\n'
+      '${onlyLight.isEmpty ? '' : '  only in light/: ${_list(onlyLight)}\n'}'
+      '${onlyDark.isEmpty ? '' : '  only in dark/:  ${_list(onlyDark)}'}',
+    );
+  }
+
+  final modeFiles = {
+    for (final mode in const ['light', 'dark']) p.normalize(p.join(tokenDir.path, mode, 'stream_tokens.dart')),
+  };
+  final colorScan = _references(libDir, modeFiles);
+  if (colorScan.filesRead == 0) {
+    _fail('Scanned no Dart files under lib/ — the reference search found nothing to read.');
+  }
+
+  final allColors = {...declared['light']!, ...declared['dark']!};
+  final unused = allColors.where((name) => !colorScan.names.contains(name) && !_allowedUnused.contains(name)).toList()
+    ..sort();
+  if (unused.isNotEmpty) {
+    failures.add(
+      '${unused.length} vendored token${unused.length == 1 ? '' : 's'} '
+      '${unused.length == 1 ? 'is' : 'are'} never referenced:\n'
+      '  ${_list(unused)}\n'
+      '  Only the root semantics belong here. A component derives its values\n'
+      '  from a StreamColorScheme field, so a token no field reads is dead —\n'
+      '  delete it, or wire up the field that should read it.',
+    );
+  }
+
+  // The dimension tokens sit beside the per-mode files rather than inside them,
+  // because the token repo publishes one set for every mode. Same rule: a
+  // constant no class reads is dead weight.
+  final dimensionsFile = File(p.join(tokenDir.path, 'stream_tokens_dimensions.dart'));
+  final dimensionsLabel = p.relative(dimensionsFile.path, from: packageRoot);
+  if (!dimensionsFile.existsSync()) _fail('Missing $dimensionsLabel');
+
+  final declaredDimensions = _declarations(dimensionsFile.readAsStringSync(), dimensionsLabel);
+  if (declaredDimensions.length < _minDimensionTokens) {
+    _fail(
+      'Only ${declaredDimensions.length} constants parsed from $dimensionsLabel, '
+      'expected at least $_minDimensionTokens.',
+    );
+  }
+  final dimensionScan = _references(libDir, {p.normalize(dimensionsFile.path)}, className: 'StreamTokensDimensions');
+  final unusedDimensions =
+      declaredDimensions.where((name) => !dimensionScan.names.contains(name) && !_allowedUnused.contains(name)).toList()
+        ..sort();
+  if (unusedDimensions.isNotEmpty) {
+    failures.add(
+      '${unusedDimensions.length} dimension token${unusedDimensions.length == 1 ? '' : 's'} '
+      '${unusedDimensions.length == 1 ? 'is' : 'are'} never referenced:\n'
+      '  ${_list(unusedDimensions)}\n'
+      '  StreamSpacing, StreamRadius and StreamLineHeight are the only readers.\n'
+      '  A dimension no class exposes belongs upstream, not here.',
+    );
+  }
+
+  // Font sizes are the one dimension group that differs per platform, so they
+  // mirror upstream's flavor split rather than sitting in the shared file. Same
+  // rules as light/dark: both must declare the same names, and each file must
+  // actually be imported — identical constant names across the two would
+  // otherwise let an orphaned flavor look referenced.
+  final fontSizeFiles = <String, File>{
+    for (final flavor in const ['android', 'ios'])
+      flavor: File(p.join(tokenDir.path, flavor, 'stream_tokens_font_size.dart')),
+  };
+  final declaredFontSizes = <String, Set<String>>{};
+  fontSizeFiles.forEach((flavor, file) {
+    final label = p.relative(file.path, from: packageRoot);
+    if (!file.existsSync()) _fail('Missing $label');
+    declaredFontSizes[flavor] = _declarations(file.readAsStringSync(), label);
+    if (declaredFontSizes[flavor]!.length < _minFontSizeTokens) {
+      _fail(
+        'Only ${declaredFontSizes[flavor]!.length} constants parsed from $label, '
+        'expected at least $_minFontSizeTokens.',
+      );
+    }
+    if (!_isImportedUnder(libDir, file, packageRoot)) {
+      failures.add(
+        '$label is never imported.\n'
+        '  Both flavors declare the same constant names, so an unused one still\n'
+        '  looks referenced. Wire it to StreamFontSize.$flavor, or delete it.',
+      );
+    }
+  });
+
+  final onlyAndroid = declaredFontSizes['android']!.difference(declaredFontSizes['ios']!);
+  final onlyIos = declaredFontSizes['ios']!.difference(declaredFontSizes['android']!);
+  if (onlyAndroid.isNotEmpty || onlyIos.isNotEmpty) {
+    failures.add(
+      'android/ and ios/ declare different font-size constants.\n'
+      '${onlyAndroid.isEmpty ? '' : '  only in android/: ${_list(onlyAndroid)}\n'}'
+      '${onlyIos.isEmpty ? '' : '  only in ios/:     ${_list(onlyIos)}'}',
+    );
+  }
+
+  final fontSizeScan = _references(
+    libDir,
+    fontSizeFiles.values.map((f) => p.normalize(f.path)).toSet(),
+    className: 'StreamTokensFontSize',
+  );
+  final unusedFontSizes = {
+    ...declaredFontSizes['android']!,
+    ...declaredFontSizes['ios']!,
+  }.where((name) => !fontSizeScan.names.contains(name) && !_allowedUnused.contains(name)).toList()..sort();
+  if (unusedFontSizes.isNotEmpty) {
+    failures.add(
+      '${unusedFontSizes.length} font-size token${unusedFontSizes.length == 1 ? '' : 's'} '
+      '${unusedFontSizes.length == 1 ? 'is' : 'are'} never referenced:\n'
+      '  ${_list(unusedFontSizes)}\n'
+      '  StreamFontSize.android and StreamFontSize.ios are the only readers.',
+    );
+  }
+
+  // Any other Dart file in the token directory is vendored too. Rather than
+  // being invisible to this check, it has to be accounted for — that is how a
+  // whole file of dead constants stayed hidden once already.
+  final covered = {
+    ...modeFiles,
+    p.normalize(dimensionsFile.path),
+    ...fontSizeFiles.values.map((f) => p.normalize(f.path)),
+  };
+  final uncovered =
+      tokenDir
+          .listSync(recursive: true)
+          .whereType<File>()
+          .where((f) => f.path.endsWith('.dart') && !covered.contains(p.normalize(f.path)))
+          .map((f) => p.relative(f.path, from: packageRoot))
+          .toList()
+        ..sort();
+  if (uncovered.isNotEmpty) {
+    failures.add(
+      '${uncovered.length} vendored token file${uncovered.length == 1 ? '' : 's'} '
+      '${uncovered.length == 1 ? 'is' : 'are'} not covered by this check:\n'
+      '  ${_list(uncovered)}\n'
+      '  Give it a branch here, or delete it. A vendored file this check cannot\n'
+      '  see is exactly the dead weight it exists to prevent.',
+    );
+  }
+
+  // A name nobody declares cannot be "allowed to be unreferenced" — it is a
+  // typo, or a leftover from a constant that has since been deleted.
+  final staleAllowed = _allowedUnused.difference({...allColors, ...declaredDimensions}).toList()..sort();
+  if (staleAllowed.isNotEmpty) {
+    failures.add(
+      '${staleAllowed.length} entr${staleAllowed.length == 1 ? 'y' : 'ies'} in _allowedUnused '
+      'match${staleAllowed.length == 1 ? 'es' : ''} no declaration:\n'
+      '  ${_list(staleAllowed)}\n'
+      '  Remove them — an allowlist nobody can account for is not an allowlist.',
+    );
+  }
+
+  if (failures.isNotEmpty) _fail(failures.join('\n\n'));
+
+  stdout.writeln(
+    '✓ ${declared['light']!.length} color tokens, ${declaredDimensions.length} dimension tokens and '
+    '${declaredFontSizes['android']!.length} font sizes per flavor, all referenced; '
+    'light/ and dark/ and android/ and ios/ in agreement '
+    '(${colorScan.filesRead} Dart files scanned).',
+  );
+}
+
+/// The `static const <name>` declarations in a vendored token file.
+///
+/// [source] is stripped of comments and string literals first, so a name in
+/// prose is neither counted as a declaration nor able to keep a dead constant
+/// alive. [label] names the file in any failure message.
+Set<String> _declarations(String source, String label) {
+  final code = _stripCommentsAndStrings(source);
+  final names = RegExp(
+    // The type annotation is optional: the color files omit it, the dimension
+    // file needs `double` so its values satisfy Radius and TextStyle.
+    r'static\s+const\s+(?:[\w<>?,\s]+\s+)?(\w+)\s*=',
+  ).allMatches(code).map((m) => m.group(1)!).toSet();
+
+  // A declaration this pattern misses is invisible to every check below — it
+  // escapes both the dead-token scan and the light/dark parity check. Compare
+  // against a count that cannot drift out of step with it.
+  final occurrences = RegExp(r'static\s+const\s').allMatches(code).length;
+  if (occurrences != names.length) {
+    _fail(
+      'Parsed ${names.length} declarations from $label but found $occurrences `static const` occurrences.\n'
+      '  Some declaration form is not understood, and whatever this pattern\n'
+      '  misses is silently exempt from every check below.',
+    );
+  }
+  return names;
+}
+
+/// Result of a reference scan: the names found, and how many files were read.
+///
+/// The file count is what separates "nothing is unreferenced" from "nothing was
+/// examined".
+typedef _Scan = ({Set<String> names, int filesRead});
+
+/// Every `<className>.<name>` reference under [libDir], ignoring the vendored
+/// files in [declaringFiles] so a declaration does not count as its own use.
+///
+/// Comments and string literals are stripped before matching. Without that a
+/// stale `[StreamTokens.foo]` in a doc comment keeps a dead constant alive —
+/// and `comment_references` is disabled in `analysis_options.yaml`, so such a
+/// reference is not even a lint.
+_Scan _references(Directory libDir, Set<String> declaringFiles, {String className = 'StreamTokens'}) {
+  final pattern = RegExp(
+    '$className'
+    r'\.(\w+)',
+  );
+  final found = <String>{};
+  var filesRead = 0;
+  for (final entity in libDir.listSync(recursive: true)) {
+    if (entity is! File || !entity.path.endsWith('.dart')) continue;
+    if (declaringFiles.contains(p.normalize(entity.path))) continue;
+    filesRead++;
+    found.addAll(pattern.allMatches(_stripCommentsAndStrings(entity.readAsStringSync())).map((m) => m.group(1)!));
+  }
+  return (names: found, filesRead: filesRead);
+}
+
+/// Drops comments and string literals, keeping everything else verbatim.
+///
+/// Crude on purpose: it only has to be right for the vendored token files and
+/// the primitives that read them, which are constant declarations and field
+/// defaults rather than arbitrary Dart.
+String _stripCommentsAndStrings(String source) {
+  final out = StringBuffer();
+  var i = 0;
+  while (i < source.length) {
+    if (source.startsWith('//', i)) {
+      while (i < source.length && source[i] != '\n') {
+        i++;
+      }
+      continue;
+    }
+    if (source.startsWith('/*', i)) {
+      final end = source.indexOf('*/', i + 2);
+      i = end == -1 ? source.length : end + 2;
+      continue;
+    }
+    final ch = source[i];
+    if (ch == "'" || ch == '"') {
+      final delim = source.startsWith(ch * 3, i) ? ch * 3 : ch;
+      i += delim.length;
+      while (i < source.length) {
+        if (source[i] == r'\') {
+          i += 2;
+          continue;
+        }
+        if (source.startsWith(delim, i)) {
+          i += delim.length;
+          break;
+        }
+        i++;
+      }
+      continue;
+    }
+    out.write(ch);
+    i++;
+  }
+  return out.toString();
+}
+
+/// Whether any Dart file under [libDir] imports [file].
+///
+/// Matched on the file's basename inside an import directive, which is enough
+/// here: the vendored token file names are unique across the package.
+///
+/// Deliberately matches the raw source rather than the comment-stripped form —
+/// the path is itself a string literal, so stripping strings would remove the
+/// very thing being looked for. Anchoring to the start of a line keeps a
+/// commented-out import from counting.
+bool _isImportedUnder(Directory libDir, File file, String packageRoot) {
+  final needle = RegExp(
+    "^\\s*import\\s+['\"][^'\"]*${RegExp.escape(p.basename(file.path))}['\"]",
+    multiLine: true,
+  );
+  for (final entity in libDir.listSync(recursive: true)) {
+    if (entity is! File || !entity.path.endsWith('.dart')) continue;
+    if (p.normalize(entity.path) == p.normalize(file.path)) continue;
+    if (needle.hasMatch(entity.readAsStringSync())) return true;
+  }
+  return false;
+}
+
+String _list(Iterable<String> names) {
+  final sorted = names.toList()..sort();
+  if (sorted.length <= 12) return sorted.join(', ');
+  return '${sorted.take(12).join(', ')} … and ${sorted.length - 12} more';
+}
+
+Never _fail(String message) {
+  stderr.writeln('✗ $message');
+  exit(1);
+}