[DOC] simple mcp client with sampling capability

[yarnabrina]

Motivation and Context

The is no documented MCP client example how to support MCP servers using sampling capability. This PR attempts to add a basic example.

How Has This Been Tested?

This changes are subset of my personal repository. It is not tested in a production system, but thoroughly tested locally.

Breaking Changes

No

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

Related #1205

[yarnabrina]

@maxisbey @felixweinberger here's the first attempt, please have a look.

[yarnabrina]

@felixweinberger @maxisbey updated with the main branch, requesting review.

[yarnabrina]

@felixweinberger @maxisbey while waiting for the review, can you please help me understand why is CI failing? The failures with respect to missing files or in files under src are not changes introduced here, so should have failed in other PR's as well as in main based on my understanding.

[felixweinberger]

@felixweinberger @maxisbey while waiting for the review, can you please help me understand why is CI failing? The failures with respect to missing files or in files under src are not changes introduced here, so should have failed in other PR's as well as in main based on my understanding.

Looks like you have a bunch of typing failures:

pyright..................................................................Failed
- hook id: pyright
- duration: 9.61s
- exit code: 1

WARNING: there is a new pyright version available (v1.1.405 -> v1.1.406).
Please install the new version or set PYRIGHT_PYTHON_FORCE_VERSION to `latest`

/home/runner/work/python-sdk/python-sdk/src/mcp/cli/__init__.py
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/__init__.py:3:18 - error: Type of "app" is unknown (reportUnknownVariableType)
/home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:15:12 - error: Import "typer" could not be resolved (reportMissingImports)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:34:1 - error: Type of "app" is unknown (reportUnknownVariableType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:34:7 - error: Type of "Typer" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:211:2 - error: Type of "command" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:211:2 - error: Untyped function decorator obscures type of function; ignoring decorator (reportUntypedFunctionDecorator)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:222:2 - error: Type of "command" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:222:2 - error: Untyped function decorator obscures type of function; ignoring decorator (reportUntypedFunctionDecorator)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:224:22 - error: Type of "Argument" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:230:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:241:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:305:2 - error: Type of "command" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:305:2 - error: Untyped function decorator obscures type of function; ignoring decorator (reportUntypedFunctionDecorator)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:307:22 - error: Type of "Argument" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:313:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:362:2 - error: Type of "command" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:362:2 - error: Untyped function decorator obscures type of function; ignoring decorator (reportUntypedFunctionDecorator)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:364:22 - error: Type of "Argument" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:370:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:378:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:389:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:396:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/cli/cli.py:404:9 - error: Type of "Option" is unknown (reportUnknownMemberType)
/home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:9:6 - error: Import "websockets.asyncio.client" could not be resolved (reportMissingImports)
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:9:50 - error: Type of "ws_connect" is unknown (reportUnknownVariableType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:10:6 - error: Import "websockets.typing" could not be resolved (reportMissingImports)
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:10:31 - error: Type of "Subprotocol" is unknown (reportUnknownVariableType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:49:70 - error: Type of "ws" is unknown (reportUnknownVariableType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:57:27 - error: Type of "raw_text" is unknown (reportUnknownVariableType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:59:76 - error: Argument type is unknown
    Argument corresponds to parameter "json_data" in function "model_validate_json" (reportUnknownArgumentType)
  /home/runner/work/python-sdk/python-sdk/src/mcp/client/websocket.py:75:27 - error: Type of "send" is unknown (reportUnknownMemberType)
31 errors, 0 warnings, 0 informations

Are you using any features only available in Python 3.13+? Please make sure any examples fir the repo, i.e. they need to be compatible with 3.10+

[felixweinberger]

Hi @yarnabrina thank you for this contribution.

Could you attach a screen recording or gif to your PR description demonstrating the example? That would make it easier to evaluate it.

Also for examples we aim to not introduce any dependencies on specific model providers like OpenAI or Anthropic - examples should be constructed in such a way that users can easily replace the relevant API calls with whatever provider they need or have access to.

[felixweinberger]

Can we rename this to LLM_API_KEY to not call out any specific model providers.

See simple chatbot example for inspiration how to provide an LLMClient to illustrate that any provider can be used:

python-sdk/examples/clients/simple-chatbot/mcp_simple_chatbot/main.py

Line 215 in c81ff64

class LLMClient:

[felixweinberger]

Please don't import specific provider dependencies, examples should ideally be such that users can easily substitute their preferred APIs as needed.

[yarnabrina]

Hi @felixweinberger , I'll check on the openai to generic part, but I'm really not sure what I can do on the type checking part. This PR only adds new files under examples, so I'm not sure I'm following why type check failures are happening under src/mcp. Can you please help me understand that?

Does main branch pass these checks for you?

[I'll update openai to generic calls using requests in a day or two.]