creation of a tool without any server instance knowledge

For now we can only create a tool with server.registerTool(name, options, callback)
I means to create one tool I'm force to have already create the server an to have its instance

In opposite, in Langchain management, you create tools with import {tool} from '@langchain/core/tools'; function and create the tool anywhere,
Then you associate it with the graph / llm you want

The advantage of the Langchain management is I can for example create a library of tools, then in another package, create a server and associate the tools to it.

Here I cannot. Or I miss something in the documentation ?

Is there's any way to construct a tool outside of a mcpServer instance ?

Start by reading the current server.registerTool(name, options, callback) API and the SDK documentation around tool creation. Compare that flow with the requested standalone tool construction and later association with a server, using the LangChain example in the issue as context. Done means the supported design or limitation is documented and, if supported, a tool can be created without an MCP server instance and then associated with one.