diff --git a/src/lib/__tests__/cardElements.test.tsx b/src/lib/__tests__/cardElements.test.tsx
index 51ae4165..6e159c2c 100644
--- a/src/lib/__tests__/cardElements.test.tsx
+++ b/src/lib/__tests__/cardElements.test.tsx
@@ -1,5 +1,7 @@
+import React from "react";
 import { describe, it, expect } from "vitest";
-import { estimateHeight, levelColor } from "../cardElements";
+import { estimateHeight, levelColor, createBlock, MAX_BIO_LENGTH } from "../cardElements";
+import type { CardData } from "../cardDataFetcher";
 import type { CardRenderOptions } from "../cardOptions";
 
 describe("cardElements utility functions", () => {
@@ -107,4 +109,47 @@ describe("cardElements utility functions", () => {
       expect(levelColor(15, 10, mockTheme)).toBe("#15803d"); // > 1
     });
   });
+
+  describe("createBlock - bio", () => {
+    const mockTheme = {
+      bg: "#fff",
+      panel: "#f8f9fa",
+      text: "#000",
+      subtext: "#666",
+      border: "#ccc",
+      success: "#0f0",
+      accent: "#3b82f6",
+    };
+
+    const mockData = {
+      profile: {
+        avatarUrl: "https://example.com/avatar.png",
+        name: "Test User",
+        login: "testuser",
+        bio: "",
+      }
+    } as unknown as CardData;
+
+    it("truncates bio if it exceeds MAX_BIO_LENGTH", () => {
+      const longBio = "A".repeat(MAX_BIO_LENGTH + 10);
+      mockData.profile.bio = longBio;
+
+      const element = createBlock("bio", mockData, mockTheme, new Set()) as React.ReactElement;
+      // @ts-expect-error - inline bypass for complex React tree props
+      const bioDiv = (element as React.ReactElement).props.children[1].props.children[2];
+      const renderedText = bioDiv.props.children;
+      expect(renderedText).toBe("A".repeat(MAX_BIO_LENGTH) + "...");
+    });
+
+    it("does not truncate bio if it is within MAX_BIO_LENGTH", () => {
+      const shortBio = "A".repeat(MAX_BIO_LENGTH);
+      mockData.profile.bio = shortBio;
+
+      const element = createBlock("bio", mockData, mockTheme, new Set()) as React.ReactElement;
+      // @ts-expect-error - inline bypass for complex React tree props
+      const bioDiv = (element as React.ReactElement).props.children[1].props.children[2];
+      const renderedText = bioDiv.props.children;
+      expect(renderedText).toBe(shortBio);
+    });
+  });
 });
diff --git a/src/lib/cardElements.tsx b/src/lib/cardElements.tsx
index 0e0b73cd..5bcf4b54 100644
--- a/src/lib/cardElements.tsx
+++ b/src/lib/cardElements.tsx
@@ -7,6 +7,8 @@ import type {
 } from "./cardOptions";
 import { resolveBlockLayout } from "./cardOptions";
 
+export const MAX_BIO_LENGTH = 110;
+
 export type ThemePalette = {
   bg: string;
   panel: string;
@@ -98,8 +100,8 @@ function createBioBlock(data: CardData, theme: ThemePalette): ReactElement {
         </div>
         {data.profile.bio ? (
           <div style={{ color: theme.subtext, fontSize: 13, maxWidth: 470 }}>
-            {data.profile.bio.length > 110
-              ? `${data.profile.bio.slice(0, 110)}...`
+            {data.profile.bio.length > MAX_BIO_LENGTH
+              ? `${data.profile.bio.slice(0, MAX_BIO_LENGTH)}...`
               : data.profile.bio}
           </div>
         ) : null}