diff --git a/tests/integration/_support/mcp.py b/tests/integration/_support/mcp.py
index 73eb73ab214..e6ae70f27e9 100644
--- a/tests/integration/_support/mcp.py
+++ b/tests/integration/_support/mcp.py
@@ -44,13 +44,17 @@ class McpPeer:
     spec_path: Path | None = None
     consumed: list[int] = field(default_factory=lambda: [0])
 
-    def drain(self) -> tuple[dict[str, object], ...]:
+    def drain(self, *, include_negotiation: bool = False) -> tuple[dict[str, object], ...]:
         if self.record is not None:
             lines: Final = self.record.read_text().splitlines() if self.record.exists() else []
             fresh: Final = tuple(json.loads(line) for line in lines[self.consumed[0] :])
             self.consumed[0] = len(lines)
-            return fresh
-        return tuple(self.calls.get_nowait() for _ in range(self.calls.qsize()))
+            return tuple(item for item in fresh if include_negotiation or "negotiation" not in item)
+        return tuple(
+            item
+            for item in (self.calls.get_nowait() for _ in range(self.calls.qsize()))
+            if include_negotiation or "negotiation" not in item
+        )
 
     def registration(self) -> dict[str, object]:
         if self.transport == "stdio":
diff --git a/tests/integration/mcp/test_mcp_transports.py b/tests/integration/mcp/test_mcp_transports.py
index 0cd36a9f808..8d2ddcc1e73 100644
--- a/tests/integration/mcp/test_mcp_transports.py
+++ b/tests/integration/mcp/test_mcp_transports.py
@@ -231,7 +231,7 @@ def test_pinned_revision_pairs_list_and_call_through_gateway(
 
         peer.drain()
         negotiated: Final = asyncio.run(exercise())
-        observed: Final = peer.drain()
+        observed: Final = peer.drain(include_negotiation=True)
         negotiations: Final = tuple(
             (item["negotiation"]["requested"], item["negotiation"]["returned"])
             for item in observed
diff --git a/tests/unit/integration_support/test_conformance.py b/tests/unit/integration_support/test_conformance.py
index db102b9cfea..abc8ea8728f 100644
--- a/tests/unit/integration_support/test_conformance.py
+++ b/tests/unit/integration_support/test_conformance.py
@@ -1,6 +1,7 @@
 import hashlib
 import json
 import os
+import queue
 from pathlib import Path
 from typing import Final
 from unittest.mock import Mock, patch
@@ -50,6 +51,33 @@ async def test_negotiation_records_preserve_the_peer_call_contract() -> None:
     assert records[0]["negotiation"] == {"requested": "2025-03-26", "returned": "2025-03-26"}
 
 
+@pytest.mark.parametrize("file_backed", (False, True))
+def test_peer_drain_preserves_received_requests(tmp_path: Path, file_backed: bool) -> None:
+    from integration._support.mcp import McpPeer
+
+    request: Final = {"body": {"method": "tools/call"}, "headers": {"authorization": "synthetic"}}
+    negotiation: Final = {"body": {}, "headers": {}, "negotiation": {"requested": "2025-03-26", "returned": "2025-03-26"}}
+    records: Final = (request, negotiation)
+    observed: Final[queue.Queue[dict[str, object]]] = queue.Queue()
+    path: Final = tmp_path / "peer.jsonl" if file_backed else None
+    if path is not None:
+        path.write_text("".join(json.dumps(record) + "\n" for record in records))
+    else:
+        for record in records:
+            observed.put(record)
+    peer: Final = McpPeer("http://peer", observed, record=path)
+    assert peer.drain() == (request,)
+    assert peer.drain() == ()
+    if path is not None:
+        with path.open("a") as sink:
+            sink.write("".join(json.dumps(record) + "\n" for record in records))
+    else:
+        for record in records:
+            observed.put(record)
+    assert peer.drain(include_negotiation=True) == records
+    assert peer.drain(include_negotiation=True) == ()
+
+
 @pytest.mark.parametrize("explicit", (False, True))
 def test_owned_proxy_isolates_automatic_coverage_unless_requested(
     tmp_path: Path, monkeypatch: pytest.MonkeyPatch, explicit: bool