Why are some ML Commons tools available via HTTP but not listed under MCP tools in OpenSearch 3.3

OpenSearch
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1

Versions (relevant - OpenSearch/Dashboard/Server OS/Browser): 3.3

Describe the issue:

noticed that certain tools (like LogPatternAnalysisTool) are available and callable through the regular ML Commons endpoints. for example, I can run them via

POST /_plugins/_ml/tools/_execute/LogPatternAnalysisTool

or see them with

GET /_plugins/_ml/tools/_list

Screenshot 2025-11-07 at 15.54.30
Screenshot 2025-11-07 at 15.54.301830×940 200 KB

but they don’t appear under

GET /_plugins/_ml/mcp/tools/_list

which means they aren’t exposed through the built-in MCP server

I do have an MCP connector configured (verified via /_plugins/_ml/connectors/_search), so I’m trying to understand:

  • Is there a configuration or registration step to make existing tools (like LogPatternAnalysisTool) visible to the MCP server?

  • Or is the MCP server currently exposing only a subset of tools?

  • Where in the source or docs can I find the list of tools officially supported by the MCP server in 3.3?

Configuration:

Relevant Logs or Screenshots:

2

@jpjp According to the OpenSearch Documentation, this the list of available tools.

When the MCP starts, it doesn’t expose any tools, and you need to register them with MCP.