diff --git a/src/components/MarketplaceVoteButton.test.tsx b/src/components/MarketplaceVoteButton.test.tsx
new file mode 100644
index 00000000..980bc021
--- /dev/null
+++ b/src/components/MarketplaceVoteButton.test.tsx
@@ -0,0 +1,91 @@
+import { cleanup, render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
+import { DirectoryVoteButton } from "@/components/directory/DirectoryVoteButton";
+import { McpVoteButton } from "@/components/mcp/McpVoteButton";
+import { PromptVoteButton } from "@/components/prompts/PromptVoteButton";
+import { SkillVoteButton } from "@/components/skills/SkillVoteButton";
+
+const forms = [
+  {
+    name: "directory",
+    render: () => (
+      <DirectoryVoteButton
+        listingId="listing-1"
+        initialUpvotes={0}
+        initialDownvotes={0}
+        initialScore={0}
+        initialUserVote={null}
+      />
+    ),
+  },
+  {
+    name: "MCP",
+    render: () => (
+      <McpVoteButton
+        slug="listing-1"
+        initialUpvotes={0}
+        initialDownvotes={0}
+        initialScore={0}
+        initialUserVote={null}
+      />
+    ),
+  },
+  {
+    name: "prompt",
+    render: () => (
+      <PromptVoteButton
+        slug="listing-1"
+        initialUpvotes={0}
+        initialDownvotes={0}
+        initialScore={0}
+        initialUserVote={null}
+      />
+    ),
+  },
+  {
+    name: "skill",
+    render: () => (
+      <SkillVoteButton
+        slug="listing-1"
+        initialUpvotes={0}
+        initialDownvotes={0}
+        initialScore={0}
+        initialUserVote={null}
+      />
+    ),
+  },
+];
+
+describe("marketplace vote errors", () => {
+  beforeEach(() => {
+    vi.stubGlobal("fetch", vi.fn());
+  });
+
+  afterEach(() => {
+    cleanup();
+    vi.unstubAllGlobals();
+  });
+
+  it.each(forms)("shows API errors when the $name vote request fails", async ({ render: renderForm }) => {
+    vi.mocked(fetch).mockResolvedValue(
+      new Response(JSON.stringify({ error: "Vote denied" }), { status: 403 })
+    );
+
+    render(renderForm());
+    await userEvent.click(screen.getByTitle("Upvote"));
+
+    expect(await screen.findByRole("alert")).toHaveTextContent("Vote denied");
+    expect(screen.getByTitle("Upvote")).toBeEnabled();
+  });
+
+  it("shows a fallback error when a vote request fails at the network layer", async () => {
+    vi.mocked(fetch).mockRejectedValue(new Error("offline"));
+
+    render(forms[0].render());
+    await userEvent.click(screen.getByTitle("Upvote"));
+
+    expect(await screen.findByRole("alert")).toHaveTextContent("Failed to update vote");
+    expect(screen.getByTitle("Upvote")).toBeEnabled();
+  });
+});
diff --git a/src/components/directory/DirectoryVoteButton.tsx b/src/components/directory/DirectoryVoteButton.tsx
index 343691a6..02a60c5f 100644
--- a/src/components/directory/DirectoryVoteButton.tsx
+++ b/src/components/directory/DirectoryVoteButton.tsx
@@ -23,9 +23,11 @@ export function DirectoryVoteButton({
   const [score, setScore] = useState(initialScore);
   const [userVote, setUserVote] = useState<number | null>(initialUserVote);
   const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
 
   async function handleVote(voteType: 1 | -1) {
     setLoading(true);
+    setError(null);
     try {
       const res = await fetch(`/api/directory/${listingId}/vote`, {
         method: "POST",
@@ -33,50 +35,60 @@ export function DirectoryVoteButton({
         body: JSON.stringify({ vote_type: voteType }),
       });
 
-      if (res.ok) {
-        const data = await res.json();
-        setUpvotes(data.upvotes);
-        setDownvotes(data.downvotes);
-        setScore(data.score);
-        setUserVote(data.user_vote);
+      if (!res.ok) {
+        const data = await res.json().catch(() => ({}));
+        setError(data.error || "Failed to update vote");
+        return;
       }
+
+      const data = await res.json();
+      setUpvotes(data.upvotes);
+      setDownvotes(data.downvotes);
+      setScore(data.score);
+      setUserVote(data.user_vote);
     } catch {
-      // silently fail
+      setError("Failed to update vote");
+    } finally {
+      setLoading(false);
     }
-    setLoading(false);
   }
 
   return (
-    <div className="flex items-center gap-1">
-      <button
-        onClick={() => handleVote(1)}
-        disabled={loading}
-        className={`p-1.5 rounded-md transition-colors ${
-          userVote === 1
-            ? "text-green-500 bg-green-500/10"
-            : "text-muted-foreground hover:text-green-500 hover:bg-green-500/10"
-        } disabled:opacity-50`}
-        title="Upvote"
-      >
-        <ThumbsUp className="h-4 w-4" />
-      </button>
-      <span className={`text-sm font-medium min-w-[2ch] text-center ${
-        score > 0 ? "text-green-500" : score < 0 ? "text-red-500" : "text-muted-foreground"
-      }`}>
-        {score}
-      </span>
-      <button
-        onClick={() => handleVote(-1)}
-        disabled={loading}
-        className={`p-1.5 rounded-md transition-colors ${
-          userVote === -1
-            ? "text-red-500 bg-red-500/10"
-            : "text-muted-foreground hover:text-red-500 hover:bg-red-500/10"
-        } disabled:opacity-50`}
-        title="Downvote"
-      >
-        <ThumbsDown className="h-4 w-4" />
-      </button>
+    <div>
+      <div className="flex items-center gap-1">
+        <button
+          type="button"
+          onClick={() => handleVote(1)}
+          disabled={loading}
+          className={`p-1.5 rounded-md transition-colors ${
+            userVote === 1
+              ? "text-green-500 bg-green-500/10"
+              : "text-muted-foreground hover:text-green-500 hover:bg-green-500/10"
+          } disabled:opacity-50`}
+          title="Upvote"
+        >
+          <ThumbsUp className="h-4 w-4" />
+        </button>
+        <span className={`text-sm font-medium min-w-[2ch] text-center ${
+          score > 0 ? "text-green-500" : score < 0 ? "text-red-500" : "text-muted-foreground"
+        }`}>
+          {score}
+        </span>
+        <button
+          type="button"
+          onClick={() => handleVote(-1)}
+          disabled={loading}
+          className={`p-1.5 rounded-md transition-colors ${
+            userVote === -1
+              ? "text-red-500 bg-red-500/10"
+              : "text-muted-foreground hover:text-red-500 hover:bg-red-500/10"
+          } disabled:opacity-50`}
+          title="Downvote"
+        >
+          <ThumbsDown className="h-4 w-4" />
+        </button>
+      </div>
+      {error && <p role="alert" className="mt-1 text-xs text-destructive">{error}</p>}
     </div>
   );
 }
diff --git a/src/components/mcp/McpVoteButton.tsx b/src/components/mcp/McpVoteButton.tsx
index 83712923..8a7a8cfe 100644
--- a/src/components/mcp/McpVoteButton.tsx
+++ b/src/components/mcp/McpVoteButton.tsx
@@ -23,9 +23,11 @@ export function McpVoteButton({
   const [score, setScore] = useState(initialScore);
   const [userVote, setUserVote] = useState<number | null>(initialUserVote);
   const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
 
   async function handleVote(voteType: 1 | -1) {
     setLoading(true);
+    setError(null);
     try {
       const res = await fetch(`/api/mcp/${slug}/vote`, {
         method: "POST",
@@ -33,22 +35,29 @@ export function McpVoteButton({
         body: JSON.stringify({ vote_type: voteType }),
       });
 
-      if (res.ok) {
-        const data = await res.json();
-        setUpvotes(data.upvotes);
-        setDownvotes(data.downvotes);
-        setScore(data.score);
-        setUserVote(data.user_vote);
+      if (!res.ok) {
+        const data = await res.json().catch(() => ({}));
+        setError(data.error || "Failed to update vote");
+        return;
       }
+
+      const data = await res.json();
+      setUpvotes(data.upvotes);
+      setDownvotes(data.downvotes);
+      setScore(data.score);
+      setUserVote(data.user_vote);
     } catch {
-      // silently fail
+      setError("Failed to update vote");
+    } finally {
+      setLoading(false);
     }
-    setLoading(false);
   }
 
   return (
-    <div className="flex items-center gap-1">
+    <div>
+      <div className="flex items-center gap-1">
       <button
+        type="button"
         onClick={() => handleVote(1)}
         disabled={loading}
         className={`p-1.5 rounded-md transition-colors ${
@@ -66,6 +75,7 @@ export function McpVoteButton({
         {score}
       </span>
       <button
+        type="button"
         onClick={() => handleVote(-1)}
         disabled={loading}
         className={`p-1.5 rounded-md transition-colors ${
@@ -77,6 +87,8 @@ export function McpVoteButton({
       >
         <ThumbsDown className="h-4 w-4" />
       </button>
+      </div>
+      {error && <p role="alert" className="mt-1 text-xs text-destructive">{error}</p>}
     </div>
   );
 }
diff --git a/src/components/prompts/PromptVoteButton.tsx b/src/components/prompts/PromptVoteButton.tsx
index 977e8475..4cdbe69c 100644
--- a/src/components/prompts/PromptVoteButton.tsx
+++ b/src/components/prompts/PromptVoteButton.tsx
@@ -23,9 +23,11 @@ export function PromptVoteButton({
   const [score, setScore] = useState(initialScore);
   const [userVote, setUserVote] = useState<number | null>(initialUserVote);
   const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
 
   async function handleVote(voteType: 1 | -1) {
     setLoading(true);
+    setError(null);
     try {
       const res = await fetch(`/api/prompts/${slug}/vote`, {
         method: "POST",
@@ -33,22 +35,29 @@ export function PromptVoteButton({
         body: JSON.stringify({ vote_type: voteType }),
       });
 
-      if (res.ok) {
-        const data = await res.json();
-        setUpvotes(data.upvotes);
-        setDownvotes(data.downvotes);
-        setScore(data.score);
-        setUserVote(data.user_vote);
+      if (!res.ok) {
+        const data = await res.json().catch(() => ({}));
+        setError(data.error || "Failed to update vote");
+        return;
       }
+
+      const data = await res.json();
+      setUpvotes(data.upvotes);
+      setDownvotes(data.downvotes);
+      setScore(data.score);
+      setUserVote(data.user_vote);
     } catch {
-      // silently fail
+      setError("Failed to update vote");
+    } finally {
+      setLoading(false);
     }
-    setLoading(false);
   }
 
   return (
-    <div className="flex items-center gap-1">
+    <div>
+      <div className="flex items-center gap-1">
       <button
+        type="button"
         onClick={() => handleVote(1)}
         disabled={loading}
         className={`p-1.5 rounded-md transition-colors ${
@@ -66,6 +75,7 @@ export function PromptVoteButton({
         {score}
       </span>
       <button
+        type="button"
         onClick={() => handleVote(-1)}
         disabled={loading}
         className={`p-1.5 rounded-md transition-colors ${
@@ -77,6 +87,8 @@ export function PromptVoteButton({
       >
         <ThumbsDown className="h-4 w-4" />
       </button>
+      </div>
+      {error && <p role="alert" className="mt-1 text-xs text-destructive">{error}</p>}
     </div>
   );
 }
diff --git a/src/components/skills/SkillVoteButton.tsx b/src/components/skills/SkillVoteButton.tsx
index a92ceaa1..95816038 100644
--- a/src/components/skills/SkillVoteButton.tsx
+++ b/src/components/skills/SkillVoteButton.tsx
@@ -23,9 +23,11 @@ export function SkillVoteButton({
   const [score, setScore] = useState(initialScore);
   const [userVote, setUserVote] = useState<number | null>(initialUserVote);
   const [loading, setLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
 
   async function handleVote(voteType: 1 | -1) {
     setLoading(true);
+    setError(null);
     try {
       const res = await fetch(`/api/skills/${slug}/vote`, {
         method: "POST",
@@ -33,22 +35,29 @@ export function SkillVoteButton({
         body: JSON.stringify({ vote_type: voteType }),
       });
 
-      if (res.ok) {
-        const data = await res.json();
-        setUpvotes(data.upvotes);
-        setDownvotes(data.downvotes);
-        setScore(data.score);
-        setUserVote(data.user_vote);
+      if (!res.ok) {
+        const data = await res.json().catch(() => ({}));
+        setError(data.error || "Failed to update vote");
+        return;
       }
+
+      const data = await res.json();
+      setUpvotes(data.upvotes);
+      setDownvotes(data.downvotes);
+      setScore(data.score);
+      setUserVote(data.user_vote);
     } catch {
-      // silently fail
+      setError("Failed to update vote");
+    } finally {
+      setLoading(false);
     }
-    setLoading(false);
   }
 
   return (
-    <div className="flex items-center gap-1">
+    <div>
+      <div className="flex items-center gap-1">
       <button
+        type="button"
         onClick={() => handleVote(1)}
         disabled={loading}
         className={`p-1.5 rounded-md transition-colors ${
@@ -66,6 +75,7 @@ export function SkillVoteButton({
         {score}
       </span>
       <button
+        type="button"
         onClick={() => handleVote(-1)}
         disabled={loading}
         className={`p-1.5 rounded-md transition-colors ${
@@ -77,6 +87,8 @@ export function SkillVoteButton({
       >
         <ThumbsDown className="h-4 w-4" />
       </button>
+      </div>
+      {error && <p role="alert" className="mt-1 text-xs text-destructive">{error}</p>}
     </div>
   );
 }