diff --git a/backend/services/knowledge_cards.py b/backend/services/knowledge_cards.py
index dc48c54..9d7fe05 100644
--- a/backend/services/knowledge_cards.py
+++ b/backend/services/knowledge_cards.py
@@ -196,3 +196,40 @@ def effective(db, domain: str, project_id: str | None = None, at: str | None = N
             continue
         result.append(card)
     return result
+
+
+# ---------------------------------------------------------------- AC-26
+# 运行时的"本次预审补充说明"只影响**本次运行**（run_instruction 落在运行对象上，
+# 见 03 §9.3）。要把它变成持久知识，唯一途径是**显式提议为草稿**，且草稿走正常
+# 审核流程；指令本身不得改变工具权限。
+RUN_SCOPE_FIELDS = ("run_instruction", "tools", "allowed_tools", "permissions", "engine")
+
+
+def draft_from_run_instruction(db, project_id: str, run_id: str, body: dict, actor: str):
+    """把一次运行的补充说明转成**待审草稿**（AC-26）。
+
+    三条约束：
+    1. 只产草稿，绝不因"运行中说过"而直接生效
+    2. 指令不得携带工具/权限/引擎字段——扩大工具授权必须走独立提议与审核
+    3. 保留来源运行，便于回溯"这条知识从哪次运行来"
+    """
+    forbidden = sorted(field for field in RUN_SCOPE_FIELDS if field in body)
+    if forbidden:
+        raise ValueError(
+            "本次预审补充说明不能持久化工具权限或执行引擎；"
+            f"请移除这些字段并通过独立提议与审核：{forbidden}"
+        )
+    if not body.get("name") or not body.get("kind"):
+        raise ValueError("转为持久知识需要明确的名称与类型")
+
+    origin = body.get("origin", "manual")
+    if origin not in ORIGINS:
+        raise ValueError(f"来源取值须为 {' 或 '.join(ORIGINS)}")
+    # 运行指令天然没有历史来源，历史来源必须另行提供证据
+    if origin == "history_derived":
+        raise ValueError("运行补充说明不能声明为历史提炼；历史提炼需提供来源事件或证据")
+
+    enriched = dict(body, derived_from_run=run_id, proposed_via="run_instruction")
+    return propose(db, enriched, actor, project_id, origin=origin,
+                   card_scope=body.get("card_scope", "project"),
+                   team_id=body.get("team_id"))
diff --git a/backend/test_knowledge_cards.py b/backend/test_knowledge_cards.py
index deb001f..e32919b 100644
--- a/backend/test_knowledge_cards.py
+++ b/backend/test_knowledge_cards.py
@@ -220,5 +220,47 @@ class EffectiveFilterTests(KnowledgeCardTestCase):
                 self.assertIn("不是项目知识卡片", str(ctx.exception))
 
 
+class RunInstructionScopeTests(KnowledgeCardTestCase):
+    """AC-26：运行补充说明只影响当前运行；持久化只能形成草稿，且不得扩大工具权限。"""
+
+    def draft_from_run(self, body, actor="demo-manager"):
+        with store.transaction(self.db_path) as db:
+            return cards.draft_from_run_instruction(db, "DEMO-A", "run-1", body, actor)
+
+    def test_instruction_becomes_a_draft_never_a_published_card(self):
+        draft = self.draft_from_run(rule_body(id="corporate.from_run"))
+        self.assertEqual(draft["status"], "draft")
+        with store.transaction(self.db_path) as db:
+            published = [row for row in store.listing(db, "component_version")
+                         if row.get("component_id") == "corporate.from_run"]
+        self.assertEqual(published, [], "运行中说过的话不得直接成为生效知识")
+
+    def test_instruction_cannot_widen_tool_permissions(self):
+        for field in ("allowed_tools", "tools", "permissions", "engine", "run_instruction"):
+            with self.subTest(field=field):
+                body = rule_body(id="corporate.tool_grab")
+                body[field] = ["terminal"]
+                with self.assertRaises(ValueError) as ctx:
+                    self.draft_from_run(body)
+                self.assertIn("不能持久化工具权限", str(ctx.exception))
+
+    def test_instruction_cannot_claim_history_derived_origin(self):
+        with self.assertRaises(ValueError) as ctx:
+            self.draft_from_run(rule_body(id="corporate.fake_history", origin="history_derived"))
+        self.assertIn("不能声明为历史提炼", str(ctx.exception))
+
+    def test_draft_records_which_run_it_came_from(self):
+        mock = self.draft_from_run(rule_body(id="corporate.traced"))
+        with store.transaction(self.db_path) as db:
+            row = store.get(db, "component_draft", mock["id"])
+        self.assertEqual(row["derived_from_run"], "run-1")
+        self.assertEqual(row["proposed_via"], "run_instruction")
+
+    def test_hard_gate_still_applies_to_run_derived_cards(self):
+        with self.assertRaises(ValueError) as ctx:
+            self.draft_from_run(rule_body(id="corporate.run_hard", effect="hard"))
+        self.assertIn("正式制度或授权依据", str(ctx.exception))
+
+
 if __name__ == "__main__":
     unittest.main()