Screen superseded backlog tasks and stalled zero-diff PRs

.github/workflows/issue-monster.md

@@ -298,9 +298,30 @@ on:
               }
               return null;
             };
+            // Cookie-labeled issues are auto-generated backlog tasks. Keep only the
+            // newest open issue for an exact normalized topic so superseded reports
+            // do not consume another agent assignment.
+            const latestAutoGeneratedIssueByTopic = new Map();
+            for (const issue of issuesWithDetails) {
+              const labels = issue.labels.map(label => label.name.toLowerCase());
+              if (!labels.includes('cookie')) continue;
+              const topic = normalizeTopic(issue.title);
+              if (topic.length < MIN_TOPIC_LENGTH) continue;
+              const latest = latestAutoGeneratedIssueByTopic.get(topic);
+              if (!latest || new Date(issue.created_at) > new Date(latest.created_at)) {
+                latestAutoGeneratedIssueByTopic.set(topic, issue);
+              }
+            }
+            const findSupersedingIssue = (issue) => {
+              const topic = normalizeTopic(issue.title);
+              if (topic.length < MIN_TOPIC_LENGTH) return null;
+              const latest = latestAutoGeneratedIssueByTopic.get(topic);
+              return latest?.number !== issue.number ? latest : null;
+            };
 
             // Filter and score issues
             const retryBlockedIssues = [];
+            const supersededIssues = [];
             const scoredIssues = issuesWithDetails
               .filter(issue => {
                 // Exclude issues that already have assignees
@@ -346,6 +367,15 @@ on:
                   return false;
                 }
 
+                // Do not auto-queue stale generated backlog tasks when a newer
+                // open issue already covers the same normalized topic.
+                const supersedingIssue = findSupersedingIssue(issue);
+                if (supersedingIssue) {
+                  core.info(`Skipping #${issue.number}: superseded by newer auto-generated issue #${supersedingIssue.number}`);
+                  supersededIssues.push({ number: issue.number, supersedingNumber: supersedingIssue.number });
+                  return false;
+                }
+
                 // Block topics that Copilot already attempted twice or more without a merge.
                 // These require human review before another agent session is spent.
                 const retryBlock = findRetryBlock(issue.title);
@@ -437,6 +467,9 @@ on:
             if (retryBlockedIssues.length > 0) {
               core.warning(`🛑 ${retryBlockedIssues.length} issue(s) were retry-blocked and excluded from assignment:\n${retryBlockedList}`);
             }
+            if (supersededIssues.length > 0) {
+              core.info(`Staleness pre-flight: ${supersededIssues.length} auto-generated issue(s) were superseded and excluded: ${supersededIssues.map(i => `#${i.number}→#${i.supersedingNumber}`).join(', ')}`);
+            }
 
             core.setOutput('issue_count', scoredIssues.length);
             core.setOutput('issue_numbers', issueNumbers);
@@ -556,6 +589,7 @@ The issue search has already been performed in the pre-activation job with smart
 - ✅ Excluded issues that have sub-issues (parent/organizing issues)
 - ✅ Excluded issues with closed or merged PRs (treating those as complete)
 - ✅ Excluded issues with open PRs from Copilot coding agent (already being worked on)
+- ✅ Excluded stale auto-generated backlog issues when a newer open issue has the same normalized topic
 - 🛑 Excluded **retry-blocked topics**: issues whose normalized title matches two or more Copilot PRs that were closed without merging
 - ✅ Prioritized issues with labels: good-first-issue, bug, security, documentation, enhancement, feature, performance, tech-debt, refactoring