diff --git a/packages/plugins/openapi/src/sdk/plugin.test.ts b/packages/plugins/openapi/src/sdk/plugin.test.ts
index 826bda7e..6b5e7ca2 100644
--- a/packages/plugins/openapi/src/sdk/plugin.test.ts
+++ b/packages/plugins/openapi/src/sdk/plugin.test.ts
@@ -540,6 +540,39 @@ layer(TestLayer)("OpenAPI Plugin", (it) => {
     }),
   );
 
+  it.effect("listSourceBindings returns [] for a removed source", () =>
+    // Regression: the React bindings atom revalidates after a removeSpec
+    // (sourceWriteKeys invalidate it) before unmount. The store used to
+    // throw StorageError("source does not exist"), which surfaced to the
+    // browser as a 500. A removed source has no bindings — return [].
+    Effect.gen(function* () {
+      const httpClient = yield* HttpClient.HttpClient;
+      const clientLayer = Layer.succeed(HttpClient.HttpClient, httpClient);
+      const executor = yield* createExecutor(
+        makeTestConfig({
+          plugins: [
+            openApiPlugin({ httpClientLayer: clientLayer }),
+            memorySecretsPlugin(),
+          ] as const,
+        }),
+      );
+
+      yield* executor.openapi.addSpec({
+        spec: specJson,
+        scope: TEST_SCOPE,
+        namespace: "removable",
+        baseUrl: "",
+      });
+      yield* executor.openapi.removeSpec("removable", TEST_SCOPE);
+
+      const bindings = yield* executor.openapi.listSourceBindings(
+        "removable",
+        TEST_SCOPE,
+      );
+      expect(bindings).toEqual([]);
+    }),
+  );
+
   // -------------------------------------------------------------------------
   // Multi-scope shadowing — regression suite covering the bug class where
   // store reads/writes that don't pin scope_id collapse onto whichever row
diff --git a/packages/plugins/openapi/src/sdk/store.ts b/packages/plugins/openapi/src/sdk/store.ts
index 1dc00e49..4231eb4d 100644
--- a/packages/plugins/openapi/src/sdk/store.ts
+++ b/packages/plugins/openapi/src/sdk/store.ts
@@ -419,8 +419,7 @@ export const makeDefaultOpenapiStore = ({
           : new Date(row.updated_at as string),
     });
 
-  const validateBindingTarget = (params: {
-    readonly sourceId: string;
+  const validateBindingScopes = (params: {
     readonly sourceScope: string;
     readonly targetScope: string;
   }) =>
@@ -445,6 +444,18 @@ export const makeDefaultOpenapiStore = ({
           }),
         );
       }
+    });
+
+  const validateBindingTarget = (params: {
+    readonly sourceId: string;
+    readonly sourceScope: string;
+    readonly targetScope: string;
+  }) =>
+    Effect.gen(function* () {
+      yield* validateBindingScopes({
+        sourceScope: params.sourceScope,
+        targetScope: params.targetScope,
+      });
       const source = yield* adapter.findOne({
         model: "openapi_source",
         where: [
@@ -701,8 +712,7 @@ export const makeDefaultOpenapiStore = ({
 
     listSourceBindings: (sourceId, sourceScope) =>
       Effect.gen(function* () {
-        yield* validateBindingTarget({
-          sourceId,
+        yield* validateBindingScopes({
           sourceScope,
           targetScope: sourceScope,
         });
@@ -729,8 +739,7 @@ export const makeDefaultOpenapiStore = ({
 
     resolveSourceBinding: (sourceId, sourceScope, slot) =>
       Effect.gen(function* () {
-        yield* validateBindingTarget({
-          sourceId,
+        yield* validateBindingScopes({
           sourceScope,
           targetScope: sourceScope,
         });