diff --git a/tests/run_agent/test_anthropic_prompt_cache_policy.py b/tests/run_agent/test_anthropic_prompt_cache_policy.py
index ba6e54f0372..56e146d358c 100644
--- a/tests/run_agent/test_anthropic_prompt_cache_policy.py
+++ b/tests/run_agent/test_anthropic_prompt_cache_policy.py
@@ -75,6 +75,46 @@ class TestOpenRouter:
         assert agent._anthropic_prompt_cache_policy() == (False, False)
 
 
+class TestKimiMoonshotOnOpenRouter:
+    """Kimi/Moonshot on OpenRouter honour envelope-layout cache_control (#25970)."""
+
+    def test_kimi_k26_on_openrouter_caches_with_envelope_layout(self):
+        agent = _make_agent(
+            provider="openrouter",
+            base_url="https://openrouter.ai/api/v1",
+            api_mode="chat_completions",
+            model="moonshotai/kimi-k2.6",
+        )
+        assert agent._anthropic_prompt_cache_policy() == (True, False)
+
+    def test_moonshot_v1_on_openrouter_caches_with_envelope_layout(self):
+        agent = _make_agent(
+            provider="openrouter",
+            base_url="https://openrouter.ai/api/v1",
+            api_mode="chat_completions",
+            model="moonshotai/moonshot-v1-8k",
+        )
+        assert agent._anthropic_prompt_cache_policy() == (True, False)
+
+    def test_kimi_on_nous_portal_caches_with_envelope_layout(self):
+        agent = _make_agent(
+            provider="nous",
+            base_url="https://api.nousresearch.com/v1",
+            api_mode="chat_completions",
+            model="moonshotai/kimi-k2.6",
+        )
+        assert agent._anthropic_prompt_cache_policy() == (True, False)
+
+    def test_kimi_on_non_openrouter_host_does_not_cache(self):
+        agent = _make_agent(
+            provider="custom",
+            base_url="https://api.moonshot.cn/v1",
+            api_mode="chat_completions",
+            model="moonshotai/kimi-k2.6",
+        )
+        assert agent._anthropic_prompt_cache_policy() == (False, False)
+
+
 class TestThirdPartyAnthropicGateway:
     """Third-party gateways speaking the Anthropic protocol (MiniMax, Zhipu GLM, LiteLLM)."""