fix: preserve disconnected conformance fixture responses

CHANGELOG.md

@@ -7,6 +7,16 @@ and this project uses [Semantic Versioning](https://semver.org/spec/v2.0.0.html)
 
 ## [Unreleased]
 
+## [0.6.1] - 2026-10-29
+
+### Fixed
+
+- Preserve legacy fixture tool results while their SSE response stream is
+  disconnected so clients can recover them with `Last-Event-ID`. Validate
+  delayed resumption repeatedly before publishing fixture images. This removes
+  catalog-order-dependent header-validation timeouts and the fixture's SSE
+  polling timeout.
+
 ## [0.6.0] - 2026-10-14
 
 ### Changed

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "cf-integration"
-version = "0.6.0"
+version = "0.6.1"
 edition = "2024"
 rust-version = "1.97"
 license = "Apache-2.0"

docker/mcp-conformance-server.Dockerfile

@@ -14,6 +14,11 @@ RUN git clone https://github.com/modelcontextprotocol/conformance.git mcp-confor
 WORKDIR /opt/mcp-conformance/examples/servers/typescript
 RUN npm ci
 
+COPY docker/mcp-typescript-sdk-resumption.patch /tmp/mcp-typescript-sdk-resumption.patch
+RUN test "$(node -p "require('./node_modules/@modelcontextprotocol/sdk/package.json').version")" = "1.29.0" \
+    && git -C /opt/mcp-conformance apply --check --directory=examples/servers/typescript/node_modules/@modelcontextprotocol/sdk /tmp/mcp-typescript-sdk-resumption.patch \
+    && git -C /opt/mcp-conformance apply --directory=examples/servers/typescript/node_modules/@modelcontextprotocol/sdk /tmp/mcp-typescript-sdk-resumption.patch
+
 COPY docker/mcp-conformance.patch /tmp/mcp-conformance.patch
 RUN git apply --check /tmp/mcp-conformance.patch && git apply /tmp/mcp-conformance.patch
 

docker/mcp-typescript-sdk-resumption.patch

@@ -0,0 +1,30 @@
+--- a/dist/esm/server/webStandardStreamableHttp.js
++++ b/dist/esm/server/webStandardStreamableHttp.js
+@@ -699,14 +699,16 @@
+             throw new Error(`No connection established for request ID: ${String(requestId)}`);
+         }
+         const stream = this._streamMapping.get(streamId);
+-        if (!this._enableJsonResponse && stream?.controller && stream?.encoder) {
++        if (!this._enableJsonResponse) {
+             // For SSE responses, generate event ID if event store is provided
+             let eventId;
+             if (this._eventStore) {
+                 eventId = await this._eventStore.storeEvent(streamId, message);
+             }
+             // Write the event to the response stream
+-            this.writeSSEEvent(stream.controller, stream.encoder, message, eventId);
++            if (stream?.controller && stream?.encoder) {
++                this.writeSSEEvent(stream.controller, stream.encoder, message, eventId);
++            }
+         }
+         if (isJSONRPCResultResponse(message) || isJSONRPCErrorResponse(message)) {
+             this._requestResponseMap.set(requestId, message);
+@@ -717,7 +719,7 @@
+             const allResponsesReady = relatedIds.every(id => this._requestResponseMap.has(id));
+             if (allResponsesReady) {
+                 if (!stream) {
+-                    throw new Error(`No connection established for request ID: ${String(requestId)}`);
++                    return;
+                 }
+                 if (this._enableJsonResponse && stream.resolveJson) {
+                     // All responses ready, send as JSON

scripts/smoke_harness_images.py

@@ -5,13 +5,58 @@
 import subprocess
 import time
 from pathlib import Path
+from urllib.request import Request, urlopen
 
 
 def docker(*arguments):
     """Run Docker and return its output, failing on nonzero exit."""
     return subprocess.check_output(["docker", *arguments], text=True).strip()
 
 
+def verify_resumption(container):
+    """Recover results produced while a legacy response stream is disconnected."""
+    address = docker("port", container, "3000/tcp")
+    url = f"http://{address}/mcp"
+    headers = {
+        "Content-Type": "application/json",
+        "Accept": "application/json, text/event-stream",
+        "MCP-Protocol-Version": "2025-11-25",
+    }
+
+    def post(message):
+        request = Request(url, data=json.dumps(message).encode(), headers=headers)
+        return urlopen(request, timeout=10)
+
+    with post({
+        "jsonrpc": "2.0", "id": 1, "method": "initialize",
+        "params": {"protocolVersion": "2025-11-25", "capabilities": {}, "clientInfo": {"name": "resumption-smoke", "version": "1"}},
+    }) as response:
+        headers["Mcp-Session-Id"] = response.headers["Mcp-Session-Id"]
+        response.read()
+    try:
+        with post({"jsonrpc": "2.0", "method": "notifications/initialized"}) as response:
+            assert response.status == 202, response.status
+        for request_id in range(2, 5):
+            with post({"jsonrpc": "2.0", "id": request_id, "method": "tools/call", "params": {"name": "test_reconnection", "arguments": {}}}) as response:
+                priming = response.read().decode()
+            fields = dict(line.split(":", 1) for line in priming.splitlines() if ":" in line)
+            event_id = fields["id"].strip()
+            time.sleep(int(fields["retry"].strip()) / 1000)
+            request = Request(url, headers={**headers, "Last-Event-ID": event_id})
+            with urlopen(request, timeout=10) as response:
+                for line in response:
+                    if line.startswith(b"data:"):
+                        message = json.loads(line[5:])
+                        break
+                else:
+                    raise AssertionError("Resumed stream ended without the tool result")
+            assert message["id"] == request_id, message
+            assert "Reconnection test completed successfully" in message["result"]["content"][0]["text"], message
+    finally:
+        with urlopen(Request(url, headers=headers, method="DELETE"), timeout=10) as response:
+            assert response.status == 200, response.status
+
+
 def main():
     """Smoke test images before their release tags are published."""
     version = os.environ["IMAGE_VERSION"]
@@ -36,7 +81,7 @@ def main():
     docker("run", "--rm", "--entrypoint", "mcp-inspector", f"{prefix}tools:{version}", "--help")
 
     for era in ("legacy", "modern", "dual"):
-        container = docker("run", "--detach", "--env", f"MCP_CONFORMANCE_SERVER_ERA={era}", f"{prefix}fixture:{version}")
+        container = docker("run", "--detach", "--publish", "127.0.0.1::3000", "--env", f"MCP_CONFORMANCE_SERVER_ERA={era}", f"{prefix}fixture:{version}")
         try:
             for _ in range(60):
                 result = subprocess.run(
@@ -51,6 +96,8 @@ def main():
                 time.sleep(1)
             else:
                 raise RuntimeError(f"{era} fixture did not become ready: {docker('logs', container)}")
+            if era in ("legacy", "dual"):
+                verify_resumption(container)
         finally:
             docker("rm", "--force", container)
     print("All harness images passed smoke checks")

src/infrastructure/assets.rs

@@ -70,6 +70,7 @@ static ASSETS: LazyLock<Vec<EmbeddedAsset>> = LazyLock::new(|| {
         asset!("docker/nginx.cf-dataplane.conf"),
         asset!("docker/nginx.cf-dataplane-standalone.conf.template"),
         asset!("docker/mcp-conformance.patch"),
+        asset!("docker/mcp-typescript-sdk-resumption.patch"),
         asset!("docker/helpers.Dockerfile"),
         asset!("docker/controlplane-principal.cel"),
         asset!("scripts/live_protocol/sitecustomize.py"),