Description

Title: Support for Parameter Passing in MCP Configuration and Runtime Context

Issue Description:

I would like to request support for parameter passing in MCP (Model Context Protocol) in two key scenarios:

1. Configuration-time Parameter Passing

Use Case: When configuring streamable HTTP connections, there's a need to pass business-specific parameters to the MCP server during initialization.

Request:

• How can we configure additional business parameters in the MCP configuration?
• What's the proper way for MCP servers to receive and process these configuration parameters?
• Is there a dedicated entry point or configuration section for custom parameters?

Example Scenario:

{"mcpServers": {
     "weather": {
              "url": "http://localhost:8000/mcp",
              "transport": "streamable_http",
              "customParams": {
                    "apiKey": "xxx",
                    "environment": "production",
                    "businessConfig": {...}
               }
          }
  }
}

2. Runtime Context Parameter Passing

Use Case: During MCP tool invocation, there's a need to pass sensitive or context-specific parameters that should:

• Be accessible to the MCP server tools
• Remain hidden from the AI model for security reasons
• Be transmitted transparently through the MCP protocol

Request:

• Support for header-like parameter passing mechanism in MCP SDK
• Secure context parameter transmission that bypasses model visibility
• Runtime parameter injection for tool execution

Previous Implementation Reference:
In previous business implementations, we used HTTP headers to pass such parameters. We're looking for similar functionality in the MCP SDK.

Expected Behavior:

// Client side - passing context parameters
await mcpClient.callTool('my-tool', {arguments: {...},
  context: {userId: "user123",
    sessionId: "session456",
    securityToken: "token789"// Hidden from model}
});

// Server side - accessing context parameters
function myTool(args, context) {
  const userId = context.userId;const securityToken = context.securityToken;
  // Tool implementation
}

Would appreciate guidance on current capabilities and potential roadmap for these features.

References

No response