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How to get session_id in tool #485
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Im having the same issue also, i can see the session_id is being passed
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from mcp.server.fastmcp import Context, FastMCP ... def _get_session_id(ctx: Context) -> int: """Get a unique session from the context.""" return id(ctx.session) ... @mcp.tool() async def your_tool(ctx: Context = None): """Some cool description""" session_id = _get_session_id(ctx) ...
Reacted by Amir Arad and Felix Weinbergerdef get_session_id(ctx: Context) -> str: """ Get a consistent session ID from an MCP context regardless of transport. Args: ctx: The MCP context object Returns: A unique session identifier that persists for the duration of the session """ if not ctx or not hasattr(ctx, 'session') or not ctx.session: raise ValueError("Invalid context - missing session") session = ctx.session # Check if we already assigned a session ID internal_attr_name = '__session_id' if hasattr(session, internal_attr_name): return getattr(session, internal_attr_name) session_id = f"s_{id(session):x}_{random.randint(0, 255):02x}" setattr(session, internal_attr_name, session_id) return session_id
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on Nov 10, 2025
in the function of @mcp.tool , i want to get session_id, how i can get it?