diff --git a/tests/integration/contracts.json b/tests/integration/contracts.json
index d12e3ae4620..ab2f9d799f7 100644
--- a/tests/integration/contracts.json
+++ b/tests/integration/contracts.json
@@ -128,6 +128,9 @@
     "tests/integration/providers/test_bedrock_auth_wire.py::test_bearer_environment_reference_loads_from_db_and_yaml_and_survives_reload": [
       "other.provider_wire.bedrock.bearer_db_yaml_survives_reload"
     ],
+    "tests/integration/providers/test_bedrock_gpt5_reasoning_wire.py::test_gpt5_reasoning_effort_is_accepted_and_sent_as_converse_reasoning_effort": [
+      "providers.bedrock_converse.gpt5_reasoning_effort_reaches_provider_as_reasoning_effort"
+    ],
     "tests/integration/streaming/test_stream_contracts.py::test_generated_tcp_partitions_preserve_unicode_text_identity_and_final_usage": [
       "other.streaming.byte_partitions.preserve_text_identity_and_usage"
     ],
diff --git a/tests/integration/providers/test_bedrock_gpt5_reasoning_wire.py b/tests/integration/providers/test_bedrock_gpt5_reasoning_wire.py
new file mode 100644
index 00000000000..d69c05ad1b1
--- /dev/null
+++ b/tests/integration/providers/test_bedrock_gpt5_reasoning_wire.py
@@ -0,0 +1,50 @@
+import json
+from typing import Final
+
+import pytest
+from integration._support.client import Gateway
+from integration._support.wire import Reply, Request, wire_server
+
+MODEL: Final = "bedrock/converse/us.openai.gpt-5.6-sol"
+TOKEN: Final = "synthetic-bedrock-bearer"
+RESPONSE: Final = json.dumps(
+    {
+        "output": {"message": {"role": "assistant", "content": [{"text": "gpt-5 reasoning wire control"}]}},
+        "stopReason": "end_turn",
+        "usage": {"inputTokens": 9, "outputTokens": 5, "totalTokens": 14},
+        "metrics": {"latencyMs": 1},
+    }
+).encode()
+
+
+def gpt5_converse_peer(request: Request) -> Reply:
+    assert request.method == "POST" and request.target == "/model/us.openai.gpt-5.6-sol/converse"
+    assert request.headers["authorization"] == f"Bearer {TOKEN}"
+    body: Final = json.loads(request.body)
+    assert body["messages"] == [{"role": "user", "content": [{"text": "synthetic reasoning request"}]}]
+    assert body["additionalModelRequestFields"] == {"reasoning": {"effort": "high"}}, body
+    assert body["inferenceConfig"] == {"maxTokens": 16}, body
+    return Reply(body=RESPONSE)
+
+
+@pytest.mark.covers("providers.bedrock_converse.gpt5_reasoning_effort_reaches_provider_as_reasoning_effort")
+def test_gpt5_reasoning_effort_is_accepted_and_sent_as_converse_reasoning_effort(gateway: Gateway) -> None:
+    with wire_server(gpt5_converse_peer) as wire, gateway.scenario() as scenario:
+        model: Final = scenario.model(
+            model=MODEL, api_key=TOKEN, aws_region_name="us-east-1", aws_bedrock_runtime_endpoint=wire.url
+        )
+        response: Final = gateway.request(
+            "POST",
+            "/v1/chat/completions",
+            {
+                "model": model,
+                "messages": [{"role": "user", "content": "synthetic reasoning request"}],
+                "reasoning_effort": "high",
+                "max_tokens": 16,
+                "cache": {"no-cache": True},
+            },
+        )
+        assert response.status_code == 200, response.text
+        assert response.json()["choices"][0]["message"]["content"] == "gpt-5 reasoning wire control", response.text
+        assert response.json()["usage"]["total_tokens"] == 14, response.text
+        assert len(wire.drain()) == 1