diff --git a/pipeline_service/gateway.py b/pipeline_service/gateway.py
index 1a99dc4..0c0fccd 100644
--- a/pipeline_service/gateway.py
+++ b/pipeline_service/gateway.py
@@ -226,10 +226,22 @@ class Gateway:
                 except Exception:
                     pass
                 # 2026-09-04 切换到模型治理新表（旧 llm 表停用）
+                # 2026-09-06 会话 agent 只接受对话能力（t2t/i2t/m2t）：
+                # 能力白名单唯一事实源 = pipeline_llm.selection.CHAT_CAPS
+                # （模块未装时兜底同值）；存量 capability 空串按 t2t 语义归一；
+                # 非对话模型（embedding/视频生成等）选中即无效，走回退链，
+                # 不落项目 default_model
+                try:
+                    from pipeline_llm.selection import CHAT_CAPS as _chat_caps
+                except ImportError:
+                    _chat_caps = ("t2t", "i2t", "m2t")
+                _cap_ph = ",".join("${c%d}$" % i for i in range(len(_chat_caps)))
+                _cap_params = {"c%d" % i: c for i, c in enumerate(_chat_caps)}
                 recs = await sor.sqlExe(
                     "SELECT id, name, org_id FROM llm_model "
-                    "WHERE status='active' AND (id=${m}$ OR vendor_model_id=${m}$) LIMIT 1",
-                    {"m": model_id})
+                    "WHERE status='active' AND (id=${m}$ OR vendor_model_id=${m}$) "
+                    "AND COALESCE(NULLIF(capability,''),'t2t') IN (%s) LIMIT 1" % _cap_ph,
+                    dict({"m": model_id}, **_cap_params))
                 await sor.sqlExe("COMMIT", {})
                 if not recs:
                     logger.warning(f"run_message: model_id 无效（不存在或未启用）: {model_id}")