Move Prompt object instantiation from server to prompt manager

[ramjibc]

The Prompt() decorator in server.py is instantiating a Prompt object before adding it to the list of prompts. This is inconsistent with how the Tool() decorator works; it delegates tool instantiation to the tool manager.

Motivation and Context

To make the decorators consistent and create clear separation of concerns: I have moved prompt object instantiation from server.py to prompts/manager.py.

How Has This Been Tested?

I updated and ran all unit tests.

Breaking Changes

No. Users will not be impacted as the prompt() decorator's signature remains unchanged.

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update

Checklist

• I have read the MCP Documentation
• My code follows the repository's style guidelines
• New and existing tests pass locally
• I have added appropriate error handling
• I have added or updated documentation as needed

Additional context

Separation of concerns: instantiation and managements of prompt objects should be done by the prompt manager, not the server.

[ihrpr]

Thank you for working on this!
There are a few concerns:

1. API Change for Direct Usage: The add_prompt() method signature changes from accepting a Prompt to accepting a function. This breaks backwards compatibility.
2. Less Flexibility: With the old design, users could create custom Prompt objects with specific configurations before
   adding them. Now they're forced to use the manager's instantiation logic.
3. Inconsistent Manager APIs: While this makes server decorators consistent, it makes the manager APIs inconsistent:
   • ToolManager.add_tool() accepts both functions and Tool objects
   • PromptManager.add_prompt() now only accepts functions

[ramjibc]

Thank you for the review @ihrpr . I have addressed your comments, but primarily from the backward compatibility perspective. Also, I don't see this in code

Inconsistent Manager APIs: While this makes server decorators consistent, it makes the manager APIs inconsistent:
ToolManager.add_tool() accepts both functions and Tool objects
PromptManager.add_prompt() now only accepts functions

I see ToolManager.add_tool() taking only a function as input.

In any case, I have made changes such that the code doesn't break for existing users but moves it a bit closer to achieving clear separation of concerns. Let me know your comments.