[Feature] Plugin System

[CeerDecy]

Description

Plugin System: Extensible plugin architecture

Motivation

Limited Customization: Users cannot add custom functionality without modifying the core codebase, making it difficult to adapt to specific business requirements.

Possible Solution

Additional Context

[CeerDecy]

Example:
When users write client code, they pass a traceId for each tool call, but the SDK doesn't provide a way to set HTTP headers for tool calls in sse transport type, so they can only pass it through args.

This works fine when connecting to their own developed MCP servers, but once they connect to third-party MCP servers, errors occur because the third-party servers either don't set these args or don't handle the traceId.

In this case, the Proxy can use a plugin approach to determine whether to filter out the traceId based on rules.