MCP request meta data to MCP server

What feature would you like to see?

As MCP server developer, it would be nice to know which agent have requested the MCP tool.

By looking at a tool call request context from MCP server, we see:

Copilot in vscode, does send some meta data to MCP server:

RequestContext(
    ...,
    meta=Meta(
        progressToken='1106ae9e-bd94-46ef-a2c5-d26891770c41',
        vscode.conversationId='dc30885e-3edb-4744-8521-a8e63f890573',
        vscode.requestId='bf766dd8-b330-4d1d-bac5-8bfa3f71b8dc'
    ),
    ...
)  

Codex (CLI/vscode extension) doesn't send any meta data to MCP server:

RequestContext(
    ...,
    meta=Meta(progressToken=3),
    ...
)  

so no way of telling which Agent have requested the tool call.

MCP spec on meta data still seem quite open:
https://modelcontextprotocol.io/specification/2025-11-25/basic/index#meta

It would be nice for codex MCP client to send some meta data indicating the tool call requests come from codex agent, so as the MCP server developer, I can distinguish tool calls used by different Agents.

Additional information

_No response_