Streamable‑HTTP MCP Server Broken After Latest Pull

[usmanalisons]

What happened?

I am using NPM to run the source code.
After updating LibreChat to the latest main branch, a previously working streamable‑HTTP MCP server no longer initialises correctly. It fails with OAuth/token errors and eventually times out—the server stops appearing in the chat menu.

Version Information

0a357c88fb206a354f4f6c4f95129f9d8cd3e48c

Steps to Reproduce

1. Pull the latest LibreChat main branch.
2. Configure librechat.yaml as follows:

mcpServers:
  mcp-server-nodejs:
    type: streamable-http
    url: http://localhost:8000/mcp
    timeout: 60000
    initTimeout: 30000
    headers:
      X-User-ID: '{{LIBRECHAT_USER_ID}}'
      X-User-Email: '{{LIBRECHAT_USER_EMAIL}}'
      X-User-Role: '{{LIBRECHAT_USER_ROLE}}'
      Authorization: 'Bearer ${API_TOKEN}'
    serverInstructions: true
    chatMenu: true

3. did npm ci , npm run frontend , npm run backend
4. MCP server running on port 8000.
5. Observe that the tool does not appear in the chat dropdown.

Debug Logs(api/logs)

2025-06-28T11:45:22.829Z info: Configuring social logins...
2025-06-28T11:45:22.829Z info: Configuring OpenID Connect...
2025-06-28T11:45:22.967Z info: OpenID Connect configured.
2025-06-28T11:45:22.976Z info: Server listening at http://localhost:3080
2025-06-28T11:45:22.977Z info: Initializing MCP servers...
2025-06-28T11:45:23.244Z debug: [mcp_get_tokens:tokens:000000000000000000000000:mcp-server-nodejs] Creating initial flow state
2025-06-28T11:45:23.247Z info: [MCP][mcp-server-nodejs] Access token missing
2025-06-28T11:45:23.249Z info: [MCP][mcp-server-nodejs] Access token missing and no refresh token available
2025-06-28T11:45:23.268Z info: [MCP][mcp-server-nodejs] Setting up OAuth event listener
2025-06-28T11:45:23.270Z info: [MCP][mcp-server-nodejs] Creating streamable-http transport: http://localhost:8000/mcp
2025-06-28T11:45:23.273Z debug: [MCP][mcp-server-nodejs] Transport sending: {"method":"initialize","params":{"protocolVersion":"2025-03-26","capabilities":{},"clientInfo":{"name":"@l... [truncated]
2025-06-28T11:45:53.273Z error: [MCP][mcp-server-nodejs] Initialization failed Connection timeout after 30000ms
2025-06-28T11:45:53.274Z info: [MCP] Initialized 0/1 app-level server(s)
2025-06-28T11:45:53.275Z warn: [MCP] 1/1 app-level server(s) failed to initialize
2025-06-28T11:45:53.276Z info: [MCP][mcp-server-nodejs] ✗ Failed
2025-06-28T11:45:53.277Z warn: [MCP] No app-level servers initialized
2025-06-28T11:45:53.279Z info: MCP servers initialized successfully
2025-06-28T11:45:53.280Z error: [MCP][mcp-server-nodejs] Connection failed: Connection timeout after 30000ms
2025-06-28T11:45:55.286Z info: [MCP][mcp-server-nodejs] Creating streamable-http transport: http://localhost:8000/mcp
2025-06-28T11:45:55.287Z debug: [MCP][mcp-server-nodejs] Transport sending: {"method":"initialize","params":{"protocolVersion":"2025-03-26","capabilities":{},"clientInfo":{"name":"@l... [truncated]
2025-06-28T11:45:55.299Z debug: [MCP][mcp-server-nodejs] Transport sending: {"method":"notifications/initialized","jsonrpc":"2.0"}
2025-06-28T11:45:55.312Z debug: [MCP][mcp-server-nodejs] Transport sending: {"method":"ping","jsonrpc":"2.0","id":2}
2025-06-28T11:45:55.314Z debug: [MCP][mcp-server-nodejs] Transport sending: {"method":"ping","jsonrpc":"2.0","id":3}
2025-06-28T11:46:23.286Z debug: [MCP][mcp-server-nodejs] Transport sending: {"jsonrpc":"2.0","method":"notifications/cancelled","params":{"requestId":0,"reason":"McpError: MCP error ... [truncated]

Error logs (api/logs)

{"level":"error","message":"[MCP][mcp-server-nodejs] Initialization failed Connection timeout after 30000ms","stack":"Error: Connection timeout after 30000ms\n    at Timeout._onTimeout (C:\\Users\\my-pc\\Desktop\\work\\LibreChat\\packages\\api\\dist\\index.js:1:46184)\n    at listOnTimeout (node:internal/timers:581:17)\n    at process.processTimers (node:internal/timers:519:7)"}
{"level":"error","message":"[MCP][mcp-server-nodejs] Connection failed: Connection timeout after 30000ms","stack":"Error: Connection timeout after 30000ms\n    at Timeout._onTimeout (C:\\Users\\my-pc\\Desktop\\work\\LibreChat\\packages\\api\\dist\\index.js:1:38069)\n    at listOnTimeout (node:internal/timers:581:17)\n    at process.processTimers (node:internal/timers:519:7)"}

Expected Behavior
The server is attempting OAuth when none are configured.

The server only works if configured as stdio, not streamable-http.

Configuration Details
LibreChat version: latest main (v0.7.8)

MCP server: Custom Node.js server listening on /mcp POST endpoint and responding correctly.

Transport type: streamable-http (tested)

What browsers are you seeing the problem on?

Chrome

Relevant log output

NO

Screenshots

No response

Code of Conduct

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

[danny-avila]

Working on my end. Try npm run reinstall if you are using npm. Run command twice if it fails initially

[usmanalisons]

@danny-avila I tried the reinstall and even clone a new LibreChat repo and used the same config which I was using before but sill no luck.
Getting the same issue of timeout.

[danny-avila]

This may be an issue with your individual MCP server. I can see from the logs you shared, it fails to connect after 30 seconds. All streamable http servers on my end are working

[usmanalisons]

I understand there could be an issue with my MCP server but the same server was working fine with the previous version until I updated and took the latest changes from Main branch.

[usmanalisons]

I switched back to the pervious version and I am able to connect with same server.

Got these logs.

2025-06-30 17:12:40 info: [MCP] Initializing app-level servers
2025-06-30 17:12:40 info: [MCP][mcp-server-nodejs] Creating streamable-http transport: http://localhost:8000/mcp
2025-06-30 17:12:50 error: [MCP][mcp-server-nodejs] Connection failed: Connection timeout
2025-06-30 17:12:52 info: [MCP][mcp-server-nodejs] Creating streamable-http transport: http://localhost:8000/mcp
2025-06-30 17:12:52 info: [MCP][mcp-server-nodejs] Capabilities: {"prompts":{},"resources":{},"tools":{}}
2025-06-30 17:12:52 info: [MCP][mcp-server-nodejs] Available tools: calculator, file_operations, weather
2025-06-30 17:12:52 info: [MCP] Initialized 1/1 app-level server(s)
2025-06-30 17:12:52 info: [MCP][mcp-server-nodejs] ✓ Initialized
2025-06-30 17:12:52 info: [MCP] All app-level servers initialized successfully
2025-06-30 17:12:52 info: No changes needed for 'USER' role permissions
2025-06-30 17:12:52 info: No changes needed for 'ADMIN' role permissions
2025-06-30 17:12:52 info: Turnstile is DISABLED (no siteKey provided).

Version Information
17b755c7d4dd3bd4e3948bd7742adea47617225e

[danny-avila]

Are you at liberty of sharing your MCP server? Also are you referring to a specific commit hash or docker image version?

[usmanalisons]

The above is a commit hash, on this commit I am able to connect but on the latest I am not.

I just built a simple MCP server using @modelcontextprotocol/sdk.
Which exposes /mcp, /see on HTTP.

[danny-avila]

can you share it? because all my basic examples using SSE and streamable HTTP are working.

[usmanalisons]

@danny-avila, please find the repo below, it's just a simple one tool MCP.

https://github.com/usmanalisons/mcp_server

[usmanalisons]

On the same server, I can connect on type=stdio using the below

mcpServers:
  mcp-server-nodejs:
    type: stdio
    command: 'node'
    args:
      - "C:\\Users\\username\\Desktop\\work\\mcp-server-nodejs\\dist\\index.js"
    env:
      LOG_LEVEL: 'info'

[danny-avila]

@usmanalisons your MCP server is not configured to use Streamable HTTP Transport. It was likely defaulting to SSE before the new option was implemented.

https://github.com/usmanalisons/mcp_server/blob/be3d6f6c9c399efa187f0318a7dcf80d46710aaf/src/server.ts#L2-L3

simply defining an /mcp route is not enough.

https://github.com/modelcontextprotocol/typescript-sdk/blob/1b14bd7fa4dcc436df0fcb2718f86dc376cdd904/src/server/streamableHttp.ts#L118

[usmanalisons]

@danny-avila thank you for your quick support I got it working with right implementation.
I have another questions

I'm trying to implement a custom LangChain tool in LibreChat that requires uploaded files from users. Is there a way to get the upoaded files in tool call?

capabilities:
  - tools
  - file_search
  - execute_code

Any help would be appreciated!

[langered]

I experience the exact same issue as described above as a flaky behaviour. Sometimes it works without problems and at other times, I run into timeouts for each server.
It happened after I upgraded the docker image from: ghcr.io/danny-avila/librechat-dev:c68cc0a550033a4369a4e6ffc523ab3bac4a0559 to ghcr.io/danny-avila/librechat-dev:0bf708915b9f61b2935aa9d75b3e58b3798c8d2b@sha256:fc81e8aa545af275fb5015fc8c34c60fa61f418fc6c4fb4be7444a83ea4e1bb8

All my MCP servers are using the streamable http protocol and are configured in librechat.yaml accordingly. None of my servers are taking as long as the timeout to start.

[danny-avila]

Configure a higher initialization timeout:

https://www.librechat.ai/docs/configuration/librechat_yaml/object_structure/mcp_servers#inittimeout

[usmanalisons]

@danny-avila I'm encountering an issue with the MCP streamable-http server.

The connection automatically disconnects after some time, and it does not reconnect automatically. The only way to restore the connection is by restarting the MCP server.

Is there a known workaround or fix for this?

[danny-avila]

Try using it from the UI if this happens. It doesn't need to stay connected, are you able to share what you see in the UI?

[coladarci]

Hey all - I landed here due to issues with/ streamable-http as well and thought this might be connected or relevant - in my case I have a remote server I'm developing that works perfectly via MCP Inspector, but when I add it to my config for Libre, the startup logs look like this:

LibreChat         | 2025-08-21 16:45:38 info: [MCP][my_mcp_server] Creating streamable-http transport: https://abc123.ngrok-free.app/
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] -------------------------------------------------┐
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] URL: https://abc123.ngrok-free.app
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] OAuth Required: false
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] Capabilities: {"tools":{}}
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] Tools: tool_one, tool_two
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] Server Instructions: undefined
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] -------------------------------------------------┘
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] Streamable-http transport closed
LibreChat         | 2025-08-21 16:45:39 error: [MCP][my_mcp_server] Transport error: This operation was aborted
LibreChat         | 2025-08-21 16:45:39 info: [MCP][my_mcp_server] Reconnecting 1/3 (delay: 2000ms)
LibreChat         | 2025-08-21 16:45:39 error: [MCP][my_mcp_server] Transport error: SSE stream disconnected: AbortError: This operation was aborted
LibreChat         | 2025-08-21 16:45:39 info: MCP servers initialized successfully. Added 2 MCP tools.
LibreChat         | 2025-08-21 16:45:41 info: [MCP][my_mcp_server] Creating streamable-http transport: https://abc123.ngrok-free.app/

Which seems like it maybe worked-ish? It connected, got stuff back and the immediately disconnected all in one go?

Then when I try, via the UI, to use the server, I get these errors:

LibreChat         | 2025-08-21 17:02:14 info: [MCP][my_mcp_server] Creating streamable-http transport: https://abc123.ngrok-free.app/
LibreChat         | 2025-08-21 17:02:14 info: [MCP][my_mcp_server] Creating streamable-http transport: https://abc123.ngrok-free.app/
LibreChat         | 2025-08-21 17:02:18 error: Tool tool_one_mcp_my_mcp_server not found in available tools
LibreChat         | 2025-08-21 17:02:18 error: Tool tool_two_mcp_my_mcp_server not found in available tools
LibreChat         | 2025-08-21 17:02:18 warn: No tools found for the specified tool calls: tool_one_mcp_my_mcp_server, tool_two_mcp_my_mcp_server

Where all the tools are namespaced and can't be found..

I'm fully prepared for this to be a problem w/ my server, but I'm stumped because this server works when connected to the inspector, Augment and Claude.

Any help is greatly appreciated!

Note: The above is for ngrok which I started to use to help debug more quickly w/ my local setup, but the errors are identical when connected to the production URL directly

[danny-avila]

see my comment here, it should clear up some information for you:
#9178 (reply in thread)

[coladarci]

Thanks for the quick reply! In looking at that comment, it appears to be around

    requiresOAuth: false
    startup: true

I have added both of those and the logs are still showing the above. In the example above, it says OAuth Required: false so I'm not sure I'm experience the same issue as you were commenting on. Perhaps I'm missing something?

[danny-avila]

how long does it take for your server to initialize? Are the logs you shared before the same after configuring these options?

Then when I try, via the UI, to use the server,

How are you trying to use the server via the UI exactly?

Currently, the MCP servers need to be initialized manually per user unless you add that flag I recommended,

    startup: true

If you're still having trouble, and would like more help, and are at liberty to share the MCP server, I can help test hands on.

[danny-avila]

I'm also working on MCP servers being automatically reinitialized when users have them selected already, or already configured for an agent, as that might also be the reason you're experiencing this error at the point of usage.

[coladarci]

Here is my config:

mcpServers:
  peek:
    type: streamable-http
    url: https://mcp.peek.com
    requiresOAuth: false
    timeout: 300000
    startup: true

Here are the startup logs:

LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] -------------------------------------------------┐
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] URL: https://mcp.peek.com
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] OAuth Required: false
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] Capabilities: {"tools":{}}
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] Tools: echo, experience_availability, experience_details, list_tags, search_experiences, search_regions
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] Server Instructions: undefined
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] -------------------------------------------------┘
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] Streamable-http transport closed
LibreChat         | 2025-08-22 02:45:08 error: [MCP][peek] Transport error: SSE stream disconnected: AbortError: This operation was aborted
LibreChat         | 2025-08-22 02:45:08 info: [MCP][peek] Reconnecting 1/3 (delay: 2000ms)
LibreChat         | 2025-08-22 02:45:08 info: MCP servers initialized successfully. Added 6 MCP tools.
LibreChat         | 2025-08-22 02:45:10 info: [MCP][peek] Creating streamable-http transport: https://mcp.peek.com/

To "use" it, I'm selecting it from the drop down and typing something into the box:

When I do that, the logs show:

LibreChat         | 2025-08-22 02:49:27 error: Tool echo_mcp_peek not found in available tools
LibreChat         | 2025-08-22 02:49:27 error: Tool experience_availability_mcp_peek not found in available tools
LibreChat         | 2025-08-22 02:49:27 error: Tool experience_details_mcp_peek not found in available tools
LibreChat         | 2025-08-22 02:49:27 error: Tool list_tags_mcp_peek not found in available tools
LibreChat         | 2025-08-22 02:49:27 error: Tool search_experiences_mcp_peek not found in available tools
LibreChat         | 2025-08-22 02:49:27 error: Tool search_regions_mcp_peek not found in available tools
LibreChat         | 2025-08-22 02:49:27 warn: No tools found for the specified tool calls: echo_mcp_peek, experience_availability_mcp_peek, experience_details_mcp_peek, list_tags_mcp_peek, search_experiences_mcp_peek, search_regions_mcp_peek

And the UI answers on its own w/out any calls to the MCP.

Does the above help? I can't easily share the code for the server, but it's a public MCP if you want to connect locally and see what you see? Appreciate all you do...