diff --git a/packages/api/src/domains/cats/services/agents/routing/artifact-tracking.ts b/packages/api/src/domains/cats/services/agents/routing/artifact-tracking.ts
index 4b73547739..e30a87e82d 100644
--- a/packages/api/src/domains/cats/services/agents/routing/artifact-tracking.ts
+++ b/packages/api/src/domains/cats/services/agents/routing/artifact-tracking.ts
@@ -84,3 +84,28 @@ export function mergeLedger(
   }
   return [...byRef.values()].sort((a, b) => b.updatedAt - a.updatedAt).slice(0, MAX_LEDGER_ENTRIES);
 }
+
+/**
+ * Filter out artifacts whose file refs no longer exist on disk.
+ * PR-type artifacts (type === 'pr') are always kept — they don't map to filesystem paths.
+ * Fail-open: if existence check throws, the artifact is kept (avoid false removals).
+ *
+ * Issue: #1067 — stale artifacts in threadMemory.recentArtifacts pollute navigation [真相源]
+ */
+export async function filterStaleArtifacts(artifacts: RecentArtifact[]): Promise<RecentArtifact[]> {
+  const fs = await import('node:fs/promises');
+  const results = await Promise.all(
+    artifacts.map(async (a) => {
+      // PR artifacts don't have filesystem refs — always keep
+      if (a.type === 'pr') return a;
+      try {
+        await fs.access(a.ref);
+        return a;
+      } catch {
+        // File doesn't exist — drop this artifact
+        return null;
+      }
+    }),
+  );
+  return results.filter((a): a is RecentArtifact => a !== null);
+}
diff --git a/packages/api/src/domains/cats/services/agents/routing/route-helpers.ts b/packages/api/src/domains/cats/services/agents/routing/route-helpers.ts
index f43b8ed41d..bd24ad8d1f 100644
--- a/packages/api/src/domains/cats/services/agents/routing/route-helpers.ts
+++ b/packages/api/src/domains/cats/services/agents/routing/route-helpers.ts
@@ -20,7 +20,7 @@ import type { Thread } from '../../stores/ports/ThreadStore.js';
 import { canViewMessage, resolveVisibleReplyParent } from '../../stores/visibility.js';
 import type { AgentMessage, AgentService } from '../../types.js';
 import type { InvocationDeps } from '../invocation/invoke-single-cat.js';
-import { extractRecentArtifacts, mergeLedger } from './artifact-tracking.js';
+import { extractRecentArtifacts, filterStaleArtifacts, mergeLedger } from './artifact-tracking.js';
 import type { CoverageMap } from './context-transport.js';
 import {
   buildCoverageMap,
@@ -801,8 +801,12 @@ export async function assembleIncrementalContext(
   }
   const mergedLedger = mergeLedger(storedLedgerArtifacts, recentArtifacts);
 
+  // Issue #1067: filter out artifacts whose files no longer exist on disk
+  // Prevents stale artifacts (e.g. deleted /tmp files) from polluting navigation [真相源]
+  const liveArtifacts = await filterStaleArtifacts(mergedLedger);
+
   const rankedSources = rankArtifactSources(
-    mergedLedger,
+    liveArtifacts,
     allThreadTasks.map((t) => ({ kind: t.kind, subjectKey: t.subjectKey ?? null, title: t.title, status: t.status })),
     { canonicalFeatureId: options?.canonicalFeatureId, threadTitle: options?.threadTitle },
   );
@@ -1347,10 +1351,12 @@ async function assembleSmartWindowContext(
       ...(finalAnchorLines.length > 0 ? { anchorSummaries: finalAnchorLines } : {}),
       ...(baton ? { baton } : {}),
       ...(activeTasks.length > 0 ? { activeTasks } : {}),
-      ...(() => {
+      ...(await (async () => {
         const merged = mergeLedger(storedFileArtifacts, recentArtifacts);
-        return merged.length > 0 ? { recentArtifacts: merged } : {};
-      })(),
+        // Issue #1067: also filter stale artifacts in briefing context
+        const live = await filterStaleArtifacts(merged);
+        return live.length > 0 ? { recentArtifacts: live } : {};
+      })()),
       ...(rankedSources.length > 0 ? { rankedSources } : {}),
     },
     navigationHeader,