Submitting an SSE MCP request from Librechat to LiteLLM broken in 0.7.8

[schwifty-brows]

What happened?

when running in 0.7.7 agent with mcp attachements were working without issue. In 0.7.8 they appear to be broken as litellm complains with

"Invalid Message bedrock requires at least one non-system message"

when further inspecting what librechat sent, this is what i see

{
  "user": "67fea0aebd23d47e2c24f16d",
  "model": "Claude 3.7 - Sonnet",
  "tools": [
    {
      "type": "function",
      "function": {
        "name": "search_confluence_mcp_comp-confluence",
        "parameters": {
          "type": "object",
          "$schema": "http://json-schema.org/draft-07/schema#",
          "required": [
            "query"
          ],
          "properties": {
            "query": {
              "type": "string",
              "description": "Search query string"
            },
            "space": {
              "anyOf": [
                {
                  "anyOf": [
                    {
                      "not": {}
                    },
                    {
                      "type": "string",
                      "description": "Optional space key"
                    }
                  ],
                  "description": "Optional space key"
                },
                {
                  "type": "null"
                }
              ],
              "description": "Optional space key"
            }
          },
          "additionalProperties": false
        },
        "description": "Search Confluence documents and pages"
      }
    }
  ],
  "stream": true,
  "messages": []
}

notice how messages is empty

this is also an issue when not using an agent

Version Information

0.7.8 latest main

Steps to Reproduce

1. load latest librechat (main)

2. make a request to latest litellm

3. see the error specified above

4. load 0.7.7 librechat

5. make a request to latest litellm

6. no error

What browsers are you seeing the problem on?

No response

Relevant log output

"Invalid Message bedrock requires at least one non-system message"

Screenshots

No response

Code of Conduct

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

[schwifty-brows]

further details

[danny-avila]

Try the simple mock MCP server of the Atlassian Confluence Search, see if it gives you the same issue.

https://github.com/danny-avila/mock_confluence_mcp

[schwifty-brows]

also, if i restrict the tool return to 10K or less characters, it seems to work (it executes way to many calls after to get more information)

[tanmaypandey7]

for anyone who comes across this in the future - we recently faced this issue and got it fixed by fixing the max context tokens to 50k in Model Provider settings.
Seems that this pruning logic got introduced somewhere between v2.2.0 and v2.4.314 in @librechat/agents package

[danny-avila]

Which model are you using? It can certainly be a problem if a low context window is being used (and a large tool output is returned).

[tanmaypandey7]

Hey Danny, i was using Claude 3.7 model. Our default context windows was ~3k tokens, the tool output was indeed large due to which it was being pruned.

Suggestion - Can we show a warning in logs somewhere in librechat notifying that pruning is happening? Figuring it out was a little unintuitive.