feat: enhance dynamic tool management with notifications and enable/disable

Summary

Enhance the Python SDK's dynamic tool management capabilities to match the TypeScript SDK by adding:

Automatic tools/list_changed notifications when tools are added/removed
Tool enable/disable functionality (temporary hiding without removal)

Background

The Python SDK currently supports adding and removing tools dynamically (see #1322), but lacks two key features present in the TypeScript SDK:

1. List Changed Notifications

The TypeScript SDK automatically sends notifications/tools/list_changed when tools are modified. This allows clients to know when they should refresh their tool list.

Python SDK gap: Currently, when calling add_tool() or remove_tool(), clients are not notified of the change and may show stale tool lists.

2. Enable/Disable Tools

The TypeScript SDK provides enable() and disable() methods on tools:

const tool = server.tool("myTool", ..., async () => { ... });
tool.disable()  // Hides from list_tools, blocks calls
tool.enable()   // Re-enables the tool
tool.remove()   // Permanently removes

Benefits:

Temporarily hide tools without losing registration
Re-enable tools without re-registering
Useful for permission-based or state-based tool visibility

Python SDK gap: Only permanent removal via remove_tool() is supported. No way to temporarily disable/re-enable tools.

References

Related PR: feat: add ability to remove tools #1322 (adds remove_tool method)
TypeScript SDK Dynamic Servers: https://github.com/modelcontextprotocol/typescript-sdk#dynamic-servers
MCP spec supports notifications/tools/list_changed

I'm not entirely sure how this should be implemented. The Typescript SDK returns an object which can be used for removing/enabling/disabling, but I'm not sure this exact thing would work well for Python given that we use decorators for registering tools. Keen to hear other's thoughts.

We could add enable_tool(self, name) and disable_tool(self, name) methods within the FastMCP class, which interfaces with the tool manager. These methods could use the existing

python-sdk/src/mcp/server/fastmcp/tools/tool_manager.py

Lines 37 to 39 in 61399b3

    
           def get_tool(self, name: str) -> Tool | None: 
        
               """Get tool by name.""" 
        
               return self._tools.get(name)

function to retrieve the tool instance, and enable or disable it. Each tool instance would include an is_enabled attribute that can be checked before the tool is executed. From there, we could send a notification via the context manager. we should also maybe do this with resources.

Is there a way to have dynamic tool management? A hacky method should also suffice my use case. But I do think that this is an important feature the SDK should support.

Found a way around this for now:

async def tool_list_update(ctx : Context, names : List[str]) -> List[str]:
    """
    inject the context and use the send_tool_list_changed() to inform client
    """
    for name in names:
        if name in dynamic_toolset:
            mcp.add_tool(dynamic_toolset[name], name = name)
    await ctx.session.send_tool_list_changed() # send the notification
    return ret

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feat: enhance dynamic tool management with notifications and enable/disable #1429

Summary

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1. List Changed Notifications

2. Enable/Disable Tools

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	def get_tool(self, name: str) -> Tool \| None:
	"""Get tool by name."""
	return self._tools.get(name)

feat: enhance dynamic tool management with notifications and enable/disable #1429

Description

Summary

Background

1. List Changed Notifications

2. Enable/Disable Tools

References

Activity

maxisbey commented on Oct 6, 2025

beaterblank commented on Oct 9, 2025

kuku929 commented on Dec 17, 2025

kuku929 commented on Dec 18, 2025

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