diff --git a/.changeset/fix-adapter-class-exports.md b/.changeset/fix-adapter-class-exports.md
new file mode 100644
index 00000000..4d5115e7
--- /dev/null
+++ b/.changeset/fix-adapter-class-exports.md
@@ -0,0 +1,7 @@
+---
+'@openzeppelin/ui-builder-adapter-evm': patch
+'@openzeppelin/ui-builder-adapter-stellar': patch
+'@openzeppelin/ui-builder-adapter-polkadot': patch
+---
+
+Re-export adapter classes (EvmAdapter, StellarAdapter, PolkadotAdapter) from package entry points. These exports were accidentally removed during the ecosystemDefinition refactor in #338, breaking exported app builds that import adapter classes directly.
diff --git a/packages/adapter-evm/src/index.ts b/packages/adapter-evm/src/index.ts
index f049025c..c1874ffe 100644
--- a/packages/adapter-evm/src/index.ts
+++ b/packages/adapter-evm/src/index.ts
@@ -7,6 +7,7 @@ import { ecosystemMetadata } from './metadata';
 import { evmNetworks } from './networks';
 
 export { ecosystemMetadata } from './metadata';
+export { EvmAdapter } from './adapter';
 
 export const ecosystemDefinition: EcosystemExport = {
   ...ecosystemMetadata,
diff --git a/packages/adapter-polkadot/src/index.ts b/packages/adapter-polkadot/src/index.ts
index a4b6a557..e057989e 100644
--- a/packages/adapter-polkadot/src/index.ts
+++ b/packages/adapter-polkadot/src/index.ts
@@ -15,6 +15,7 @@ import { ecosystemMetadata } from './metadata';
 import { polkadotNetworks } from './networks';
 
 export { ecosystemMetadata } from './metadata';
+export { PolkadotAdapter } from './adapter';
 
 export const ecosystemDefinition: EcosystemExport = {
   ...ecosystemMetadata,
diff --git a/packages/adapter-stellar/src/index.ts b/packages/adapter-stellar/src/index.ts
index 7219986f..e9632a40 100644
--- a/packages/adapter-stellar/src/index.ts
+++ b/packages/adapter-stellar/src/index.ts
@@ -6,6 +6,7 @@ import { ecosystemMetadata } from './metadata';
 import { stellarNetworks } from './networks';
 
 export { ecosystemMetadata } from './metadata';
+export { StellarAdapter } from './adapter';
 
 export const ecosystemDefinition: EcosystemExport = {
   ...ecosystemMetadata,