[BUG] Failed to get tools from external MCP server

[kalilventura]

What is the bug?
When an agent attempts to use a tool from an externally configured Model Connector and Provider (MCP) server, the request fails with a ProtectionDomain access error. This prevents the agent from connecting to the external endpoint and utilizing its tools.

The configuration was done following the steps in the official documentation.

The following error is consistently logged when the agent tries to access a tool on the external MCP server:
Denied access to: my-mcp-endpoint:443, domain ProtectionDomain
It occurs when the external endpoint is configured with both HTTP and HTTPS.

How can one reproduce the bug?
Steps to reproduce the behavior:

1. Follow the documentation doumentation
2. OpenSearch Logs

[2025-09-26T15:15:18,580][ERROR][i.m.c.t.HttpClientSseClientTransport] [dev-opensearch-node-data-0] SSE connection error
java.util.concurrent.CompletionException: java.lang.SecurityException: Denied access to: my-mcp-endpoint:443, domain ProtectionDomain  (jrt:/java.net.http <no signer certificates>)
 jdk.internal.loader.ClassLoaders$PlatformClassLoader@d8948cd
 <no principals>
 java.security.Permissions@4633b6d (
)
	at java.base/java.util.concurrent.CompletableFuture.wrapInCompletionException(CompletableFuture.java:325) ~[?:?]
	at java.base/java.util.concurrent.CompletableFuture.encodeRelay(CompletableFuture.java:414) ~[?:?]
	at java.base/java.util.concurrent.CompletableFuture.uniComposeStage(CompletableFuture.java:1235) ~[?:?]
	at java.base/java.util.concurrent.CompletableFuture.thenCompose(CompletableFuture.java:2393) ~[?:?]
	at java.net.http/jdk.internal.net.http.MultiExchange.responseAsyncImpl(MultiExchange.java:483) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.MultiExchange.lambda$responseAsync0$0(MultiExchange.java:357) ~[java.net.http:?]
	at java.base/java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:1196) ~[?:?]
	at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:556) ~[?:?]
	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1819) ~[?:?]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1095) ~[?:?]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:619) ~[?:?]
	at java.base/java.lang.Thread.run(Thread.java:1447) [?:?]
Caused by: java.lang.SecurityException: Denied access to: my-mcp-endpoint:443, domain ProtectionDomain  (jrt:/java.net.http <no signer certificates>)
 jdk.internal.loader.ClassLoaders$PlatformClassLoader@d8948cd
 <no principals>
 java.security.Permissions@4633b6d (
)
	at java.base/sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:936) ~[?:?]
	at java.net.http/jdk.internal.net.http.PlainHttpConnection.connectAsync(PlainHttpConnection.java:203) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.AsyncSSLConnection.connectAsync(AsyncSSLConnection.java:56) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.Http1Exchange.sendHeadersAsync(Http1Exchange.java:312) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.Exchange.lambda$responseAsyncImpl$0(Exchange.java:559) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.Exchange.checkFor407(Exchange.java:408) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.Exchange.lambda$responseAsyncImpl$2(Exchange.java:563) ~[java.net.http:?]
	at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:980) ~[?:?]
	at java.base/java.util.concurrent.CompletableFuture.uniHandleStage(CompletableFuture.java:996) ~[?:?]
	at java.base/java.util.concurrent.CompletableFuture.handle(CompletableFuture.java:2424) ~[?:?]
	at java.net.http/jdk.internal.net.http.Exchange.responseAsyncImpl(Exchange.java:563) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.Exchange.responseAsync(Exchange.java:385) ~[java.net.http:?]
	at java.net.http/jdk.internal.net.http.MultiExchange.responseAsyncImpl(MultiExchange.java:437) ~[java.net.http:?]
	... 7 more
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] [ERROR] (Thread-740) Operator called default onErrorDropped - reactor.core.Exceptions$ErrorCallbackNotImplemented: java.lang.SecurityException: Denied access to: my-mcp-endpoint:443, domain ProtectionDomain  (jrt:/java.net.http <no signer certificates>)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  jdk.internal.loader.ClassLoaders$PlatformClassLoader@d8948cd
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  <no principals>
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  java.security.Permissions@4633b6d (
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] )
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] reactor.core.Exceptions$ErrorCallbackNotImplemented: java.lang.SecurityException: Denied access to: my-mcp-endpoint:443, domain ProtectionDomain  (jrt:/java.net.http <no signer certificates>)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  jdk.internal.loader.ClassLoaders$PlatformClassLoader@d8948cd
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  <no principals>
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  java.security.Permissions@4633b6d (
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] )
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] Caused by: java.lang.SecurityException: Denied access to: my-mcp-endpoint:443, domain ProtectionDomain  (jrt:/java.net.http <no signer certificates>)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  jdk.internal.loader.ClassLoaders$PlatformClassLoader@d8948cd
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  <no principals>
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0]  java.security.Permissions@4633b6d (
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] )
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/sun.nio.ch.SocketChannelImpl.connect(SocketChannelImpl.java:936)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.PlainHttpConnection.connectAsync(PlainHttpConnection.java:203)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.AsyncSSLConnection.connectAsync(AsyncSSLConnection.java:56)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.Http1Exchange.sendHeadersAsync(Http1Exchange.java:312)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.Exchange.lambda$responseAsyncImpl$0(Exchange.java:559)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.Exchange.checkFor407(Exchange.java:408)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.Exchange.lambda$responseAsyncImpl$2(Exchange.java:563)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.CompletableFuture.uniHandle(CompletableFuture.java:980)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.CompletableFuture.uniHandleStage(CompletableFuture.java:996)
[2025-09-26T15:15:18,581][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.CompletableFuture.handle(CompletableFuture.java:2424)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.Exchange.responseAsyncImpl(Exchange.java:563)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.Exchange.responseAsync(Exchange.java:385)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.MultiExchange.responseAsyncImpl(MultiExchange.java:437)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.net.http/jdk.internal.net.http.MultiExchange.lambda$responseAsync0$0(MultiExchange.java:357)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:1196)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:556)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1819)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1095)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:619)
[2025-09-26T15:15:18,582][WARN ][stderr                   ] [dev-opensearch-node-data-0] 	at java.base/java.lang.Thread.run(Thread.java:1447)
[2025-09-26T15:15:28,395][ERROR][o.o.m.e.a.a.AgentUtils   ] [dev-opensearch-node-data-0] Failed to get tools from connector: WLoahpkBS7a6SdwPBhNB
org.opensearch.ml.common.exception.MLException: Unexpected error while getting MCP tools
	at org.opensearch.ml.engine.algorithms.remote.McpConnectorExecutor.getMcpToolSpecs(McpConnectorExecutor.java:143) ~[opensearch-ml-algorithms-3.2.0.0.jar:?]
	at org.opensearch.ml.engine.algorithms.agent.AgentUtils.lambda$getMCPToolSpecsFromConnector$0(AgentUtils.java:755) [opensearch-ml-algorithms-3.2.0.0.jar:?]
	at org.opensearch.core.action.ActionListener$1.onResponse(ActionListener.java:82) [opensearch-core-3.2.0.jar:3.2.0]
	at org.opensearch.ml.engine.algorithms.agent.AgentUtils.lambda$getConnector$0(AgentUtils.java:807) [opensearch-ml-algorithms-3.2.0.0.jar:?]
	at java.base/java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:909) [?:?]
	at java.base/java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:887) [?:?]
	at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:556) [?:?]
	at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2231) [?:?]
	at org.opensearch.remote.metadata.client.impl.LocalClusterIndicesClient.lambda$getDataObjectAsync$1(LocalClusterIndicesClient.java:148) [opensearch-remote-metadata-sdk-3.2.0.0.jar:?]
	at org.opensearch.core.action.ActionListener$1.onResponse(ActionListener.java:82) [opensearch-core-3.2.0.jar:3.2.0]
	at org.opensearch.action.support.TransportAction$1.onResponse(TransportAction.java:115) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.action.support.TransportAction$1.onResponse(TransportAction.java:109) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction$2.handleResponse(TransportSingleShardAction.java:298) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction$2.handleResponse(TransportSingleShardAction.java:284) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.security.transport.SecurityInterceptor$RestoringTransportResponseHandler.handleResponse(SecurityInterceptor.java:422) [opensearch-security-3.2.0.0.jar:3.2.0.0]
	at org.opensearch.transport.TransportService$ContextRestoreResponseHandler.handleResponse(TransportService.java:1587) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.transport.TransportService$DirectResponseChannel.processResponse(TransportService.java:1680) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.transport.TransportService$DirectResponseChannel.sendResponse(TransportService.java:1660) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.transport.TaskTransportChannel.sendResponse(TaskTransportChannel.java:72) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.action.support.ChannelActionListener.onResponse(ChannelActionListener.java:62) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.action.support.ChannelActionListener.onResponse(ChannelActionListener.java:45) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.action.ActionRunnable.lambda$supply$0(ActionRunnable.java:74) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.action.ActionRunnable$2.doRun(ActionRunnable.java:89) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:975) [opensearch-3.2.0.jar:3.2.0]
	at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52) [opensearch-3.2.0.jar:3.2.0]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1095) [?:?]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:619) [?:?]
	at java.base/java.lang.Thread.run(Thread.java:1447) [?:?]
Caused by: io.modelcontextprotocol.spec.McpError: Failed to wait for the message endpoint
	at io.modelcontextprotocol.client.transport.HttpClientSseClientTransport.sendMessage(HttpClientSseClientTransport.java:401) ~[?:?]
	at io.modelcontextprotocol.spec.McpClientSession.lambda$sendRequest$11(McpClientSession.java:232) ~[?:?]
	at reactor.core.publisher.MonoCreate.subscribe(MonoCreate.java:61) ~[reactor-core-3.7.5.jar:3.7.5]
	at reactor.core.publisher.Mono.subscribe(Mono.java:4576) ~[reactor-core-3.7.5.jar:3.7.5]
	at reactor.core.publisher.Mono.block(Mono.java:1778) ~[reactor-core-3.7.5.jar:3.7.5]
	at io.modelcontextprotocol.client.McpSyncClient.initialize(McpSyncClient.java:153) ~[mcp-0.9.0.jar:0.9.0]
	at org.opensearch.ml.engine.algorithms.remote.McpConnectorExecutor.getMcpToolSpecs(McpConnectorExecutor.java:112) ~[opensearch-ml-algorithms-3.2.0.0.jar:?]
	... 27 more
	Suppressed: java.lang.Exception: #block terminated with an error
		at reactor.core.publisher.BlockingSingleSubscriber.blockingGet(BlockingSingleSubscriber.java:104) ~[reactor-core-3.7.5.jar:3.7.5]
		at reactor.core.publisher.Mono.block(Mono.java:1779) ~[reactor-core-3.7.5.jar:3.7.5]
		at io.modelcontextprotocol.client.McpSyncClient.initialize(McpSyncClient.java:153) ~[mcp-0.9.0.jar:0.9.0]
		at org.opensearch.ml.engine.algorithms.remote.McpConnectorExecutor.getMcpToolSpecs(McpConnectorExecutor.java:112) ~[opensearch-ml-algorithms-3.2.0.0.jar:?]
		at org.opensearch.ml.engine.algorithms.agent.AgentUtils.lambda$getMCPToolSpecsFromConnector$0(AgentUtils.java:755) [opensearch-ml-algorithms-3.2.0.0.jar:?]
		at org.opensearch.core.action.ActionListener$1.onResponse(ActionListener.java:82) [opensearch-core-3.2.0.jar:3.2.0]
		at org.opensearch.ml.engine.algorithms.agent.AgentUtils.lambda$getConnector$0(AgentUtils.java:807) [opensearch-ml-algorithms-3.2.0.0.jar:?]
		at java.base/java.util.concurrent.CompletableFuture.uniWhenComplete(CompletableFuture.java:909) [?:?]
		at java.base/java.util.concurrent.CompletableFuture$UniWhenComplete.tryFire(CompletableFuture.java:887) [?:?]
		at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:556) [?:?]
		at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2231) [?:?]
		at org.opensearch.remote.metadata.client.impl.LocalClusterIndicesClient.lambda$getDataObjectAsync$1(LocalClusterIndicesClient.java:148) [opensearch-remote-metadata-sdk-3.2.0.0.jar:?]
		at org.opensearch.core.action.ActionListener$1.onResponse(ActionListener.java:82) [opensearch-core-3.2.0.jar:3.2.0]
		at org.opensearch.action.support.TransportAction$1.onResponse(TransportAction.java:115) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.action.support.TransportAction$1.onResponse(TransportAction.java:109) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction$2.handleResponse(TransportSingleShardAction.java:298) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.action.support.single.shard.TransportSingleShardAction$AsyncSingleAction$2.handleResponse(TransportSingleShardAction.java:284) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.security.transport.SecurityInterceptor$RestoringTransportResponseHandler.handleResponse(SecurityInterceptor.java:422) [opensearch-security-3.2.0.0.jar:3.2.0.0]
		at org.opensearch.transport.TransportService$ContextRestoreResponseHandler.handleResponse(TransportService.java:1587) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.transport.TransportService$DirectResponseChannel.processResponse(TransportService.java:1680) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.transport.TransportService$DirectResponseChannel.sendResponse(TransportService.java:1660) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.transport.TaskTransportChannel.sendResponse(TaskTransportChannel.java:72) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.action.support.ChannelActionListener.onResponse(ChannelActionListener.java:62) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.action.support.ChannelActionListener.onResponse(ChannelActionListener.java:45) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.action.ActionRunnable.lambda$supply$0(ActionRunnable.java:74) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.action.ActionRunnable$2.doRun(ActionRunnable.java:89) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.common.util.concurrent.ThreadContext$ContextPreservingAbstractRunnable.doRun(ThreadContext.java:975) [opensearch-3.2.0.jar:3.2.0]
		at org.opensearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:52) [opensearch-3.2.0.jar:3.2.0]
		at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1095) [?:?]
		at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:619) [?:?]
		at java.base/java.lang.Thread.run(Thread.java:1447) [?:?]

What is the expected behavior?
OpenSearch call my MCP agent and return the response.

What is your host/environment?

• OS: Amazon Linux
• Version 2023
• Plugins
  | mapper-size | opensearch-alerting | opensearch-anomaly-detection |
  | opensearch-asynchronous-search | opensearch-cross-cluster-replication | opensearch-custom-codecs |
  | opensearch-flow-framework | opensearch-geospatial | opensearch-index-management |
  | opensearch-job-scheduler | opensearch-knn | opensearch-ltr |
  | opensearch-ml | opensearch-neural-search | opensearch-notifications |
  | opensearch-notifications-core | opensearch-observability | opensearch-performance-analyzer |
  | opensearch-reports-scheduler | opensearch-search-relevance | opensearch-security |
  | opensearch-security-analytics | opensearch-skills | opensearch-sql |
  | opensearch-system-templates | opensearch-ubi | query-insights |
  | repository-azure | repository-s3 | |

Do you have any additional context?
I tried to run locally using the version 3.0 and 3.1 and this error not happens.

My MCP I made in python and use the /sse to connect and run the questions.

[wrigleyDan]

I'm also running into this.

My scenario:

• External MCP server created with FastMCP in Python.
• OpenSearch 3.2 and the MCP server run as Docker containers in the same network.
• The PER agent itself works. Asking it questions that it can answer by the OpenSearch internal tools I made available to the agent produces answers.
• The connection to the external MCP server does not work and fails with the error messages mentioned in the description.

Networking itself seems to be no issue as I can curl the MCP server from within the OpenSearch node:

Request:

docker exec -it opensearch curl -v http://my-mcp-server:8000/sse

Response (IP address masked):

* Host my-mcp-server:8000 was resolved.
* IPv6: (none)
* IPv4: IP_ADDRESS
*   Trying IP_ADDRESS:8000...
* Connected to my-mcp-server (<IP_ADDRESS>) port 8000
* using HTTP/1.x
> GET /sse HTTP/1.1
> Host: my-mcp-server:8000
> User-Agent: curl/8.11.1
> Accept: */*
>
* Request completely sent off
< HTTP/1.1 200 OK
< date: Thu, 02 Oct 2025 14:03:53 GMT
< server: uvicorn
< cache-control: no-store
< connection: keep-alive
< x-accel-buffering: no
< content-type: text/event-stream; charset=utf-8
< Transfer-Encoding: chunked
<
event: endpoint
data: /messages/?session_id=148f8c431a8c46fabaa3dffc1801d39e