diff --git a/__tests__/validate.test.mjs b/__tests__/validate.test.mjs
index 12a5380..79ca963 100644
--- a/__tests__/validate.test.mjs
+++ b/__tests__/validate.test.mjs
@@ -110,6 +110,20 @@ describe('真实数据全量校验', () => {
     assert.equal(routed.every((spec) => Array.isArray(spec.spec.capabilities)), true)
   })
 
+  it('智能路由三档必须完整唯一，且每档从自身开始回退', () => {
+    const indexPath = join(ROOT, 'compute', 'model-specs', '_index.json')
+    const index = JSON.parse(readFileSync(indexPath, 'utf8'))
+    const validate = compile('model-specs-index')
+
+    const duplicateTier = structuredClone(index)
+    duplicateTier.routingTiers[1] = structuredClone(duplicateTier.routingTiers[0])
+    assert.equal(validate(duplicateTier), false)
+
+    const wrongFirstFallback = structuredClone(index)
+    wrongFirstFallback.routingTiers[0].fallbackOrder = ['balanced', 'flagship', 'lightweight']
+    assert.equal(validate(wrongFirstFallback), false)
+  })
+
   it('Provider 与 coding plan 的 _index.json 应通过 providers-index schema', () => {
     const r1 = validateFile(join(ROOT, 'compute', 'providers', '_index.json'), validators)
     const r2 = validateFile(join(ROOT, 'compute', 'coding-plans', '_index.json'), validators)
diff --git a/schemas/model-specs-index.schema.json b/schemas/model-specs-index.schema.json
index c9b8909..81537b1 100644
--- a/schemas/model-specs-index.schema.json
+++ b/schemas/model-specs-index.schema.json
@@ -42,10 +42,47 @@
             "description": "该档位缺少可用候选时的量级降级/升级顺序，首项必须等于 id。"
           }
         },
+        "allOf": [
+          {
+            "if": { "properties": { "id": { "const": "flagship" } }, "required": ["id"] },
+            "then": { "properties": { "fallbackOrder": { "items": [{ "const": "flagship" }] } } }
+          },
+          {
+            "if": { "properties": { "id": { "const": "balanced" } }, "required": ["id"] },
+            "then": { "properties": { "fallbackOrder": { "items": [{ "const": "balanced" }] } } }
+          },
+          {
+            "if": { "properties": { "id": { "const": "lightweight" } }, "required": ["id"] },
+            "then": { "properties": { "fallbackOrder": { "items": [{ "const": "lightweight" }] } } }
+          }
+        ],
         "additionalProperties": false
       },
       "description": "智能路由量级定义与回退策略。"
     }
   },
+  "allOf": [
+    {
+      "properties": {
+        "routingTiers": {
+          "contains": { "type": "object", "properties": { "id": { "const": "flagship" } }, "required": ["id"] }
+        }
+      }
+    },
+    {
+      "properties": {
+        "routingTiers": {
+          "contains": { "type": "object", "properties": { "id": { "const": "balanced" } }, "required": ["id"] }
+        }
+      }
+    },
+    {
+      "properties": {
+        "routingTiers": {
+          "contains": { "type": "object", "properties": { "id": { "const": "lightweight" } }, "required": ["id"] }
+        }
+      }
+    }
+  ],
   "additionalProperties": false
 }