Call MCP tool access but finally got 400 status code (no body)

[liHai001]

What happened?

I call MCP tool and successfully return json list data.
but finally server got 400 error:

Version Information

version:
ghcr.io/danny-avila/librechat-dev-api
ghcr.io/danny-avila/librechat-dev
ghcr.io/danny-avila/librechat-rag-api-dev-lite

Steps to Reproduce

I call MCP tool and successfully return json list data.
but long text with \n, \r\n, htttp://, Chinese/Korean character

but finally server got 400 error:
"Something went wrong. Here's the specific error message we encountered: An error occurred while processing the request: 400 status code (no body)"

What browsers are you seeing the problem on?

No response

Relevant log output

Server log:


LibreChat         | 2025-07-11 03:06:28 error: [api/server/controllers/agents/client.js #sendCompletion] Operation aborted 400 status code (no body)
LibreChat         | 2025-07-11 03:06:28 error: [api/server/controllers/agents/client.js #sendCompletion] Unhandled error type 400 status code (no body)

Screenshots

No response

Code of Conduct

• I agree to follow this project's Code of Conduct

[danny-avila]

There's not enough logs to troubleshoot effectively. Please paste relevant logs that were created when reproducing the error.

Log locations:

• Docker: Project root directory ./logs
• npm: ./api/logs

There are two types of logs that can help diagnose the issue:

• debug logs (debug-YYYY-MM-DD.log)
• error logs (error-YYYY-MM-DD.log)

Error logs contain exact stack traces and are especially helpful, but both can provide valuable information.

Please only include the relevant portions of logs that correspond to when you reproduced the error.

Specific prompts/AI/MCP servers will also help determine any issues you're having.

[liHai001]

2025-07-11T03:06:23.198Z debug: [saveConvo] api/app/clients/BaseClient.js - saveMessageToDatabase #saveConvo
2025-07-11T03:06:27.785Z debug: [MCP][User: 686d054fffa05a674e8ccbad] Updated last activity timestamp: 2025-07-11T03:06:27.785Z
2025-07-11T03:06:27.785Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport sending: {"method":"ping","jsonrpc":"2.0","id":33}
2025-07-11T03:06:27.807Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport received: {"jsonrpc":"2.0","id":33,"result":{}}
2025-07-11T03:06:27.808Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Reusing active connection
2025-07-11T03:06:27.808Z debug: [MCP][User: 686d054fffa05a674e8ccbad] Updated last activity timestamp: 2025-07-11T03:06:27.808Z
2025-07-11T03:06:27.808Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport sending: {"method":"ping","jsonrpc":"2.0","id":34}
2025-07-11T03:06:28.028Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport received: {"jsonrpc":"2.0","id":34,"result":{}}
2025-07-11T03:06:28.028Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport sending: {"method":"tools/call","params":{"name":"get_jira_issues","arguments":{"assignee... [truncated]
2025-07-11T03:06:28.061Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport received: {"jsonrpc":"2.0","id":35,"result":{"content":[{"type":"text","text":"title:[SQE... [truncated]
2025-07-11T03:06:28.061Z debug: [MCP][User: 686d054fffa05a674e8ccbad] Updated last activity timestamp: 2025-07-11T03:06:28.061Z
2025-07-11T03:06:28.081Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport sending: {"jsonrpc":"2.0","method":"notifications/cancelled","params":{"requestId":35,"re... [truncated]
2025-07-11T03:06:28.082Z error: [api/server/controllers/agents/client.js #sendCompletion] Operation aborted 400 status code (no body)
2025-07-11T03:06:28.082Z error: [api/server/controllers/agents/client.js #sendCompletion] Unhandled error type 400 status code (no body)
2025-07-11T03:06:28.226Z debug: [saveConvo] api/app/clients/BaseClient.js - saveMessageToDatabase #saveConvo
2025-07-11T03:06:28.229Z debug: [AgentController] Request closed
2025-07-11T03:06:28.230Z debug: [AgentController] Performing cleanup
2025-07-11T03:06:28.230Z debug: [AgentController] Cleaning up abort controller
2025-07-11T03:06:28.230Z debug: [AgentController] Cleanup completed
``

[liHai001]

Another bug:
When create a new conversion session, every first conversion message got same 400 error:

LibreChat | 2025-07-11 06:39:46 error: [api/server/controllers/agents/client.js #sendCompletion] Operation aborted 400 status code (no body) LibreChat | 2025-07-11 06:39:46 error: [api/server/controllers/agents/client.js #sendCompletion] Unhandled error type 400 status code (no body) LibreChat | 2025-07-11 06:39:47 error: [api/server/controllers/agents/client.js #titleConvo] Error Failed to parse. Text: "". Error: SyntaxError: Unexpected end of JSON input LibreChat | LibreChat | Troubleshooting URL: https://js.langchain.com/docs/troubleshooting/errors/OUTPUT_PARSING_FAILURE/ LibreChat |

Log:
`2025-07-11T06:34:59.093Z debug: [BaseClient] Loading history:
{
conversationId: "9ee7634c-8138-4473-b721-3a7794447283",
parentMessageId: "00000000-0000-0000-0000-000000000000",
}
2025-07-11T06:34:59.239Z info: [MCP][User: 686d054fffa05a674e8ccbad] User idle for too long. Disconnecting all connections...
2025-07-11T06:34:59.240Z debug: [BaseClient] Context Count (1/2)
{
remainingContextTokens: 3678.4,
maxContextTokens: 3686.4,
}
2025-07-11T06:34:59.239Z info: [MCP][User: 686d054fffa05a674e8ccbad] Disconnecting all servers...
2025-07-11T06:34:59.239Z info: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Disconnecting...
2025-07-11T06:34:59.240Z info: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Streamable-http transport closed
2025-07-11T06:34:59.241Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Removed connection entry.
2025-07-11T06:34:59.241Z info: [MCP][User: 686d054fffa05a674e8ccbad] All connections processed for disconnection.
2025-07-11T06:34:59.241Z error: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport error: SSE stream disconnected: AbortError: This operation was aborted
2025-07-11T06:34:59.241Z info: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Reconnecting 1/3 (delay: 2000ms)
2025-07-11T06:34:59.240Z debug: [BaseClient] Context Count (2/2)
{
remainingContextTokens: 3678.4,
maxContextTokens: 3686.4,
}
2025-07-11T06:34:59.240Z debug: [BaseClient] tokenCountMap:
{
ff89ac71-bdc8-4bf7-af77-cf75fe49f8de: 5,
}
2025-07-11T06:34:59.240Z debug: [BaseClient]
{
promptTokens: 8,
remainingContextTokens: 3678.4,
payloadSize: 1,
maxContextTokens: 3686.4,
}
2025-07-11T06:34:59.241Z debug: [BaseClient] tokenCountMap
{
ff89ac71-bdc8-4bf7-af77-cf75fe49f8de: 5,
}
2025-07-11T06:34:59.241Z debug: [BaseClient] userMessage
{
messageId: "ff89ac71-bdc8-4bf7-af77-cf75fe49f8de",
parentMessageId: "00000000-0000-0000-0000-000000000000",
conversationId: "9ee7634c-8138-4473-b721-3a7794447283",
sender: "User",
text: "hello",
isCreatedByUser: true,
tokenCount: 5,
}
2025-07-11T06:34:59.258Z debug: [saveConvo] api/app/clients/BaseClient.js - saveMessageToDatabase #saveConvo
2025-07-11T06:34:59.286Z error: [api/server/controllers/agents/client.js #sendCompletion] Operation aborted 400 status code (no body)
2025-07-11T06:34:59.286Z error: [api/server/controllers/agents/client.js #sendCompletion] Unhandled error type 400 status code (no body)
2025-07-11T06:34:59.291Z debug: [saveConvo] api/app/clients/BaseClient.js - saveMessageToDatabase #saveConvo
2025-07-11T06:34:59.293Z debug: [AgentController] Request closed
2025-07-11T06:34:59.514Z error: [api/server/controllers/agents/client.js #titleConvo] Error Failed to parse. Text: "". Error: SyntaxError: Unexpected end of JSON input

Troubleshooti... [truncated]
2025-07-11T06:34:59.514Z debug: [saveConvo] api/server/services/Endpoints/agents/title.js
2025-07-11T06:34:59.516Z debug: [AgentController] Title generation started
2025-07-11T06:34:59.516Z debug: [AgentController] Title generation completed
2025-07-11T06:34:59.516Z debug: [AgentController] Performing cleanup
2025-07-11T06:34:59.516Z debug: [AgentController] Cleaning up abort controller
2025-07-11T06:34:59.516Z debug: [AgentController] Cleanup completed
2025-07-11T06:35:01.242Z info: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Creating streamable-http transport: http://109.144.5.175:31475/mcp
2025-07-11T06:35:01.243Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport sending: {"method":"initialize","params":{"protocolVersion":"2025-06-18","capabilities":{... [truncated]
2025-07-11T06:35:01.250Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport received: {"jsonrpc":"2.0","id":12,"result":{"protocolVersion":"2025-06-18","capabilities... [truncated]
2025-07-11T06:35:01.250Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport sending: {"method":"notifications/initialized","jsonrpc":"2.0"}
2025-07-11T06:35:01.253Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport sending: {"method":"ping","jsonrpc":"2.0","id":13}
2025-07-11T06:35:01.258Z debug: [MCP][User: 686d054fffa05a674e8ccbad][jira-search] Transport received: {"jsonrpc":"2.0","id":13,"result":{}}
`