diff --git a/eslint.config.mjs b/eslint.config.mjs
index ba79f9d5..9beadc1a 100644
--- a/eslint.config.mjs
+++ b/eslint.config.mjs
@@ -28,6 +28,14 @@ const chatSignalAdapterRestrictions = [
     message: "Keep chat signals in panel/shell-state.tsx as a reducer-to-Preact notification adapter.",
   },
 ];
+const chatDomainLayerRestrictions = [
+  {
+    selector:
+      "ImportDeclaration[source.value=/^(?:\\.\\.\\/)+(?:app-server|application|host|panel|presentation|ui)(?:\\/|$)|^src\\/features\\/chat\\/(?:app-server|application|host|panel|presentation|ui)(?:\\/|$)/]",
+    message:
+      "Keep chat/domain as Panel-owned meaning models and pure derivations; app-server, application, host, panel, presentation, and UI layers may depend on domain, not the reverse.",
+  },
+];
 const uiRootImportRestrictions = [
   {
     selector: "ImportDeclaration[source.value=/shared\\/ui\\/ui-root$/]",
@@ -684,6 +692,10 @@ export default defineConfig([
       "codex-panel/no-chat-state-direct-mutation": "error",
     },
   },
+  {
+    files: ["src/features/chat/domain/**/*.{ts,tsx}"],
+    rules: restrictedSyntaxRule([...sourceSyntaxRestrictions, ...chatDomainLayerRestrictions]),
+  },
   {
     files: ["src/app-server/**/*.{ts,tsx}", "src/domain/**/*.{ts,tsx}", "src/shared/**/*.{ts,tsx}"],
     rules: {
diff --git a/tests/scripts/eslint-config.test.ts b/tests/scripts/eslint-config.test.ts
index 451f4fca..13916b12 100644
--- a/tests/scripts/eslint-config.test.ts
+++ b/tests/scripts/eslint-config.test.ts
@@ -362,6 +362,32 @@ export function timestamp(): number {
 
     expect(messages).toContain("no-restricted-syntax");
   });
+
+  it("keeps chat domain independent from outer chat layers", async () => {
+    const messages = await lintSource(
+      "src/features/chat/domain/message-stream/selectors.ts",
+      `
+import type { ChatStateStore } from "../../application/state/reducer";
+
+export type Store = ChatStateStore;
+`,
+    );
+
+    expect(messages).toContain("no-restricted-syntax");
+  });
+
+  it("allows chat domain modules to depend on sibling domain modules", async () => {
+    const messages = await lintSource(
+      "src/features/chat/domain/message-stream/selectors.ts",
+      `
+import type { MessageStreamItem } from "./items";
+
+export type Item = MessageStreamItem;
+`,
+    );
+
+    expect(messages).not.toContain("no-restricted-syntax");
+  });
 });
 
 async function lintSource(filePath: string, source: string): Promise<string[]> {