diff --git a/.github/workflows/mantis-slack-desktop-smoke.yml b/.github/workflows/mantis-slack-desktop-smoke.yml
index f66f3527592..6f6f674af3b 100644
--- a/.github/workflows/mantis-slack-desktop-smoke.yml
+++ b/.github/workflows/mantis-slack-desktop-smoke.yml
@@ -281,10 +281,15 @@ jobs:
           fi
 
           status="$(jq -r '.status' "$root/mantis-slack-desktop-smoke-summary.json")"
+          screenshot_required=false
+          if [[ "$status" == "pass" ]]; then
+            screenshot_required=true
+          fi
           jq -n \
             --arg status "$status" \
             --arg candidate_sha "${{ needs.validate_ref.outputs.candidate_revision }}" \
             --arg scenario "$SCENARIO_ID" \
+            --argjson screenshot_required "$screenshot_required" \
             '{
               schemaVersion: 1,
               id: "slack-desktop-smoke",
@@ -296,7 +301,7 @@ jobs:
                 pass: ($status == "pass")
               },
               artifacts: [
-                { kind: "desktopScreenshot", lane: "candidate", label: "Slack desktop/VNC browser", path: "slack-desktop-smoke.png", targetPath: "slack-desktop.png", alt: "Slack Web desktop screenshot from the Mantis VM", width: 720, inline: true },
+                { kind: "desktopScreenshot", lane: "candidate", label: "Slack desktop/VNC browser", path: "slack-desktop-smoke.png", targetPath: "slack-desktop.png", alt: "Slack Web desktop screenshot from the Mantis VM", width: 720, inline: true, required: $screenshot_required },
                 { kind: "motionPreview", lane: "candidate", label: "Slack motion preview", path: "slack-desktop-smoke-preview.gif", targetPath: "slack-desktop-preview.gif", alt: "Animated Slack desktop preview", width: 720, inline: true, required: false },
                 { kind: "motionClip", lane: "candidate", label: "Slack change MP4", path: "slack-desktop-smoke-change.mp4", targetPath: "slack-desktop-change.mp4", required: false },
                 { kind: "fullVideo", lane: "candidate", label: "Slack desktop MP4", path: "slack-desktop-smoke.mp4", targetPath: "slack-desktop.mp4", required: false },
diff --git a/test/scripts/mantis-publish-pr-evidence.test.ts b/test/scripts/mantis-publish-pr-evidence.test.ts
index a641d83e474..fa32a10c312 100644
--- a/test/scripts/mantis-publish-pr-evidence.test.ts
+++ b/test/scripts/mantis-publish-pr-evidence.test.ts
@@ -93,6 +93,79 @@ describe("scripts/mantis/publish-pr-evidence", () => {
     expect(body).toContain("- Overall: `true`");
   });
 
+  it("allows failure manifests to omit optional visual artifacts", () => {
+    const dir = mkdtempSync(path.join(tmpdir(), "mantis-evidence-test-"));
+    writeFileSync(path.join(dir, "summary.json"), JSON.stringify({ status: "fail" }));
+    writeFileSync(path.join(dir, "report.md"), "bootstrap failed before screenshot");
+    const manifestPath = path.join(dir, "mantis-evidence.json");
+    writeFileSync(
+      manifestPath,
+      JSON.stringify({
+        schemaVersion: 1,
+        id: "slack-desktop-smoke",
+        title: "Mantis Slack Desktop Smoke QA",
+        summary: "Mantis could not finish VM setup.",
+        scenario: "slack-openclaw-desktop-smoke",
+        comparison: {
+          candidate: {
+            expected: "Slack QA and VM gateway setup pass",
+            sha: "bbb",
+            status: "fail",
+          },
+          pass: false,
+        },
+        artifacts: [
+          {
+            alt: "Slack Web desktop screenshot from the Mantis VM",
+            inline: true,
+            kind: "desktopScreenshot",
+            label: "Slack desktop/VNC browser",
+            lane: "candidate",
+            path: "slack-desktop-smoke.png",
+            required: false,
+            targetPath: "slack-desktop.png",
+          },
+          {
+            kind: "metadata",
+            label: "Slack desktop summary",
+            lane: "run",
+            path: "summary.json",
+            targetPath: "summary.json",
+          },
+          {
+            kind: "report",
+            label: "Slack desktop report",
+            lane: "run",
+            path: "report.md",
+            targetPath: "report.md",
+          },
+        ],
+      }),
+    );
+
+    const manifest = loadEvidenceManifest(manifestPath);
+    expect(manifest.artifacts.map((artifact) => artifact.targetPath)).toEqual([
+      "summary.json",
+      "report.md",
+      "mantis-evidence.json",
+    ]);
+    const body = renderEvidenceComment({
+      artifactRoot: "mantis/slack/pr-1/run-1",
+      artifactUrl: "https://github.com/openclaw/openclaw/actions/runs/1/artifacts/2",
+      manifest,
+      marker: "<!-- mantis-slack-desktop-smoke -->",
+      rawBase:
+        "https://raw.githubusercontent.com/openclaw/openclaw/qa-artifacts/mantis/slack/pr-1/run-1",
+      requestSource: "workflow_dispatch",
+      runUrl: "https://github.com/openclaw/openclaw/actions/runs/1",
+      treeUrl: "https://github.com/openclaw/openclaw/tree/qa-artifacts/mantis/slack/pr-1/run-1",
+    });
+
+    expect(body).toContain("Summary: Mantis could not finish VM setup.");
+    expect(body).toContain("- Overall: `false`");
+    expect(body).not.toContain("<img ");
+  });
+
   it("rejects artifact paths that escape the manifest directory", () => {
     const dir = mkdtempSync(path.join(tmpdir(), "mantis-evidence-test-"));
     const manifestPath = path.join(dir, "mantis-evidence.json");