diff --git a/.changeset/cli-drop-theme-default-neutral-rename.md b/.changeset/cli-drop-theme-default-neutral-rename.md
new file mode 100644
index 000000000000..3cc3b77380dd
--- /dev/null
+++ b/.changeset/cli-drop-theme-default-neutral-rename.md
@@ -0,0 +1,6 @@
+---
+'@astryxdesign/cli': patch
+---
+
+[fix] Remove the `@xds/theme-default` → `@astryxdesign/theme-neutral` collapse from the v0.1.0 upgrade codemods (module-specifiers, css-surfaces, and declare-module). `theme-default` was dropped at the v0.1.0 scope move, so no v0.1.x consumer imported it — the collapse was dead and could rewrite unrelated source (including `@xds/theme-default/theme.css` CSS imports) to a `@astryxdesign/theme-neutral` package the app never declared. The `@xds/theme-daily` → `theme-neutral` collapse (and its `defaultTheme` → `neutralTheme` export remap) is unchanged.
+@ejhammond
diff --git a/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-css-surfaces.test.mjs b/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-css-surfaces.test.mjs
index b2b72b6fc2c4..e35df94a146a 100644
--- a/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-css-surfaces.test.mjs
+++ b/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-css-surfaces.test.mjs
@@ -69,13 +69,13 @@ describe('migrate-xds-css-surfaces', () => {
     const input = [
       `@import '@xds/core/reset.css';`,
       `@import '@xds/core/xds.css';`,
-      `@import '@xds/theme-default/theme.css';`,
+      `@import '@xds/theme-daily/theme.css';`,
     ].join('\n');
     const output = await applyTransform(input);
     expect(output).toContain(`@import '@astryxdesign/core/reset.css';`);
     // xds.css is renamed to astryx.css (file rename, not just scope swap).
     expect(output).toContain(`@import '@astryxdesign/core/astryx.css';`);
-    // theme-default collapses to theme-neutral.
+    // theme-daily collapses to theme-neutral.
     expect(output).toContain(
       `@import '@astryxdesign/theme-neutral/theme.css';`,
     );
diff --git a/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-module-specifiers.test.mjs b/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-module-specifiers.test.mjs
index 93e026f446de..b637eea19cb1 100644
--- a/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-module-specifiers.test.mjs
+++ b/packages/cli/assets/codemods/transforms/v0.1.0/__tests__/migrate-xds-module-specifiers.test.mjs
@@ -17,7 +17,7 @@ describe('migrate-xds-module-specifiers', () => {
   it('renames import and export source paths including subpaths', async () => {
     const input = [
       "import {Button} from '@xds/core/Button';",
-      "import '@xds/theme-default/theme.css';",
+      "import '@xds/theme-daily/theme.css';",
       "export {LabThing} from '@xds/lab/Thing';",
       "export * from '@xds/core/theme';",
     ].join('\n');
@@ -49,18 +49,6 @@ describe('migrate-xds-module-specifiers', () => {
     expect(output).toBe(input);
   });
 
-  it('remaps defaultTheme -> neutralTheme when collapsing theme-default', async () => {
-    const output = await applyTransform(
-      `import {defaultTheme} from '@xds/theme-default';`,
-      'test.ts',
-    );
-    // Package collapses to theme-neutral; binding aliased so local usage works.
-    expect(output).toContain('neutralTheme as defaultTheme');
-    expect(output).toContain('@astryxdesign/theme-neutral');
-    expect(output).not.toContain('@xds/');
-    expect(output).not.toContain('theme-default');
-  });
-
   it('remaps defaultTheme -> neutralTheme for theme-daily and /built subpath', async () => {
     const output = await applyTransform(
       `import {defaultTheme} from '@xds/theme-daily/built';`,
@@ -72,7 +60,7 @@ describe('migrate-xds-module-specifiers', () => {
 
   it('preserves an existing alias when remapping defaultTheme', async () => {
     const output = await applyTransform(
-      `import {defaultTheme as dt} from '@xds/theme-default';`,
+      `import {defaultTheme as dt} from '@xds/theme-daily';`,
       'test.ts',
     );
     expect(output).toContain('neutralTheme as dt');
diff --git a/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-css-surfaces.mjs b/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-css-surfaces.mjs
index 762ccdeb3b73..3536fb346675 100644
--- a/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-css-surfaces.mjs
+++ b/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-css-surfaces.mjs
@@ -20,7 +20,7 @@
  *   comma-separated `\@layer a, b;` statement lists and nested blocks.
  * - `\@import '\@xds/...'` package stylesheet imports: scope rewrite, plus the
  *   `\@xds/core/xds.css` -> `\@astryxdesign/core/astryx.css` file rename and the
- *   `theme-default` / `theme-daily` -> `theme-neutral` collapse.
+ *   `theme-daily` -> `theme-neutral` collapse.
  *
  * It deliberately does NOT blindly replace every `xds` substring: a bare
  * `xds` in a comment, a custom-property value, or an unrelated identifier is
@@ -36,7 +36,7 @@ export const meta = {
     '`[data-xds-theme-prose]` / `[data-xds-media]` attribute selectors, ' +
     '`@layer xds-theme` / `@layer xds-base` cascade-layer names, and ' +
     '`@import` of @xds/* package stylesheets (scope rewrite, xds.css->astryx.css, ' +
-    'theme-default/theme-daily->theme-neutral) all become their Astryx forms.',
+    'theme-daily->theme-neutral) all become their Astryx forms.',
   pr: '#3092',
   fileExtensions: ['.css', '.scss'],
 };
@@ -60,15 +60,15 @@ function rewriteLayerPrelude(/** @type {any} */ prelude) {
 // from an @xds/* path to its @astryxdesign/* equivalent. Handles the two
 // non-mechanical cases beyond the scope swap:
 //   @xds/core/xds.css            -> @astryxdesign/core/astryx.css   (file rename)
-//   @xds/theme-default/*         -> @astryxdesign/theme-neutral/*   (collapse)
 //   @xds/theme-daily/*           -> @astryxdesign/theme-neutral/*   (collapse)
 // Returns the original value unchanged if it is not an @xds/* specifier.
 function rewriteImportSpecifier(/** @type {any} */ spec) {
   if (!spec.startsWith('@xds/')) return spec;
-  // Theme package collapse (default/daily -> neutral).
-  let next = spec
-    .replace(/^@xds\/theme-default(\/|$)/, '@astryxdesign/theme-neutral$1')
-    .replace(/^@xds\/theme-daily(\/|$)/, '@astryxdesign/theme-neutral$1');
+  // Theme package collapse (daily -> neutral).
+  let next = spec.replace(
+    /^@xds\/theme-daily(\/|$)/,
+    '@astryxdesign/theme-neutral$1',
+  );
   if (next === spec) {
     // Not a collapsed theme — plain scope swap.
     next = spec.replace(/^@xds\//, '@astryxdesign/');
diff --git a/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-declare-module.mjs b/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-declare-module.mjs
index af7cd5152a93..102446bedfb5 100644
--- a/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-declare-module.mjs
+++ b/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-declare-module.mjs
@@ -40,7 +40,6 @@ const PACKAGE_RENAMES = new Map([
   ['@xds/theme-butter', '@astryxdesign/theme-butter'],
   ['@xds/theme-chocolate', '@astryxdesign/theme-chocolate'],
   ['@xds/theme-daily', '@astryxdesign/theme-neutral'],
-  ['@xds/theme-default', '@astryxdesign/theme-neutral'],
   ['@xds/theme-gothic', '@astryxdesign/theme-gothic'],
   ['@xds/theme-matcha', '@astryxdesign/theme-matcha'],
   ['@xds/theme-neutral', '@astryxdesign/theme-neutral'],
diff --git a/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-module-specifiers.mjs b/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-module-specifiers.mjs
index b33b45d2ac30..3c7dc6652d2b 100644
--- a/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-module-specifiers.mjs
+++ b/packages/cli/assets/codemods/transforms/v0.1.0/migrate-xds-module-specifiers.mjs
@@ -27,7 +27,6 @@ const PACKAGE_RENAMES = new Map([
   ['@xds/theme-butter', '@astryxdesign/theme-butter'],
   ['@xds/theme-chocolate', '@astryxdesign/theme-chocolate'],
   ['@xds/theme-daily', '@astryxdesign/theme-neutral'],
-  ['@xds/theme-default', '@astryxdesign/theme-neutral'],
   ['@xds/theme-gothic', '@astryxdesign/theme-gothic'],
   ['@xds/theme-matcha', '@astryxdesign/theme-matcha'],
   ['@xds/theme-neutral', '@astryxdesign/theme-neutral'],
@@ -52,19 +51,16 @@ function rewriteLiteral(/** @type {any} */ node) {
   return true;
 }
 
-// @xds/theme-default and @xds/theme-daily both collapse to
-// @astryxdesign/theme-neutral, whose exported theme binding is `neutralTheme`
-// (not `defaultTheme`). When we rewrite an import from one of those packages,
-// remap a `defaultTheme` named import to `neutralTheme`, aliasing back to the
-// original local name so downstream usages keep working unchanged:
-//   import {defaultTheme} from '@xds/theme-default'
+// @xds/theme-daily collapses to @astryxdesign/theme-neutral, whose exported
+// theme binding is `neutralTheme` (not `defaultTheme`). When we rewrite an
+// import from that package, remap a `defaultTheme` named import to
+// `neutralTheme`, aliasing back to the original local name so downstream usages
+// keep working unchanged:
+//   import {defaultTheme} from '@xds/theme-daily'
 //     -> import {neutralTheme as defaultTheme} from '@astryxdesign/theme-neutral'
 // An already-aliased `{defaultTheme as x}` just has its imported name remapped.
 const THEME_EXPORT_RENAMES = new Map([['defaultTheme', 'neutralTheme']]);
-const COLLAPSED_THEME_SOURCES = new Set([
-  '@xds/theme-default',
-  '@xds/theme-daily',
-]);
+const COLLAPSED_THEME_SOURCES = new Set(['@xds/theme-daily']);
 
 function isCollapsedThemeSource(/** @type {any} */ value) {
   if (typeof value !== 'string') return false;
@@ -128,7 +124,7 @@ export default function transformer(file, api) {
 
   root.find(j.ImportDeclaration).forEach((/** @type {any} */ path) => {
     // Remap collapsed-theme export names BEFORE rewriting the source specifier
-    // (the check keys off the original @xds/theme-default|daily path).
+    // (the check keys off the original @xds/theme-daily path).
     if (isCollapsedThemeSource(path.node.source.value)) {
       hasChanges = remapThemeExportNames(path, j) || hasChanges;
     }