diff --git a/registry/examples/km-wiki-ingest/workflow.yaml b/registry/examples/km-wiki-ingest/workflow.yaml
index d86a6a5..0f1632d 100644
--- a/registry/examples/km-wiki-ingest/workflow.yaml
+++ b/registry/examples/km-wiki-ingest/workflow.yaml
@@ -388,7 +388,17 @@ config:
         return { entry: parsed.entry, envelopes, meta: parsed.meta, nodeCount: parsed.nodes.length, tripletCount: parsed.triplets.length };
       }
 
-      return planCard(input.md, input.relPath, input.repo, input.opts || {});
+      // graph /triplets/ingest 是 strict schema，拒絕未知鍵。planEnvelopes 於 envelope 上掛的
+      // 診斷鍵 _estSubrequests 不在 ingest-candidate 契約內 → post 前剝除所有 _-前綴鍵，
+      // 讓 post_one_envelope 的 body_json={{envelope}} 為契約乾淨 payload。
+      // （leo21c 實測：不剝除會回 422 unrecognized_keys "_estSubrequests"。）
+      const __plan = planCard(input.md, input.relPath, input.repo, input.opts || {});
+      __plan.envelopes = __plan.envelopes.map(function (e) {
+        const clean = {};
+        for (const k in e) { if (k.charAt(0) !== '_') clean[k] = e[k]; }
+        return clean;
+      });
+      return __plan;
 
     input:
       md: "{{fetch_card.data.body}}"