diff --git a/packages/chat-ui/test/avatar-composition.test.tsx b/packages/chat-ui/test/avatar-composition.test.tsx
index 35579bfcae..1c57b486f7 100644
--- a/packages/chat-ui/test/avatar-composition.test.tsx
+++ b/packages/chat-ui/test/avatar-composition.test.tsx
@@ -18,7 +18,7 @@ describe("avatar composition and identity resolution", () => {
     expect(corbitHtml).toContain('data-corbit="true"');
     expect(corbitHtml).toContain('aria-label="Echo Agent"');
     expect(corbitHtml).toContain("<svg");
-    expect(corbitHtml).toContain(CORBIT_DEFAULT_COLOR);
+    expect(corbitHtml).toContain(`fill:var(${CORBIT_DEFAULT_COLOR})`);
     expect(corbitHtml).not.toContain(">EA<");
   });
 
@@ -29,7 +29,9 @@ describe("avatar composition and identity resolution", () => {
     expect(AVATAR_COLORS).toContain(aliceColor);
     expect(AVATAR_COLORS).toContain(bobColor);
 
-    expect(avatarClassForPrincipal("usr_alice")).toContain(aliceColor);
+    expect(avatarClassForPrincipal("usr_alice")).toBe(
+      `bg-(${aliceColor}) text-black`,
+    );
 
     expect(avatarColorForPrincipal("usr_alice")).toBe(aliceColor);
   });
diff --git a/packages/chat-ui/test/avatar-tokens.test.ts b/packages/chat-ui/test/avatar-tokens.test.ts
new file mode 100644
index 0000000000..40f3842178
--- /dev/null
+++ b/packages/chat-ui/test/avatar-tokens.test.ts
@@ -0,0 +1,36 @@
+// happy-dom does not apply stylesheets, so the avatar identity palette is
+// locked against CSS source: :root must define exactly the four --avatar-N
+// tokens with their pinned hex values (the proposed upstream contract).
+import { describe, expect, test } from "bun:test";
+import { readFileSync } from "node:fs";
+import { dirname, join } from "node:path";
+import { fileURLToPath } from "node:url";
+
+const css = readFileSync(
+  join(dirname(fileURLToPath(import.meta.url)), "../src/styles.css"),
+  "utf8",
+);
+
+function rootBodies(): string[] {
+  return [
+    ...css.matchAll(/(?:^|\n)\s*:root\s*\{([^}]+)\}/g),
+  ].map((match) => match[1] ?? "");
+}
+
+describe("avatar token contract", () => {
+  test(":root defines exactly the four avatar pastels with pinned hex", () => {
+    const bodies = rootBodies();
+    expect(bodies.length).toBeGreaterThan(0);
+    const body = bodies[0] ?? "";
+
+    expect(body).toMatch(/--avatar-1:\s*#c5d2de\s*;/);
+    expect(body).toMatch(/--avatar-2:\s*#c1d1be\s*;/);
+    expect(body).toMatch(/--avatar-3:\s*#f7ead5\s*;/);
+    expect(body).toMatch(/--avatar-4:\s*#f2b277\s*;/);
+
+    const tokens = [...body.matchAll(/--avatar-(\d+)\s*:/g)].map(
+      (match) => match[1],
+    );
+    expect(tokens.sort()).toEqual(["1", "2", "3", "4"]);
+  });
+});