[a-akimov]

Motivation and Context

Closes #269

All clients now take the server as a command plus its arguments, identify themselves the same way, report usage errors the same way and quit cleanly on Ctrl-C.

• Launching: pass the command that starts the server and its arguments, as Go and Rust already did. TypeScript and Ruby no longer start .py servers with bare python3, which failed for the uv-managed Python server
• Client info: every client sends mcp-client- / 1.0.0
• Usage errors: printed to stderr, exit status 1
• Ctrl-C: quits like quit and shuts the server down. Go and Rust read input on a separate thread; Python reads stdin's raw stream on a daemon thread, so exiting doesn't wait for a pending read
• Tools: listed once at connect time in every client (Python listed them again on each query)
• Python: import sys at the top, drop the unused pathlib import
• .env.example: add the missing Rust one, empty Go placeholder
• Tests: the mock server rejects clients that don't send the expected client info, the smoke test launches it as a command and checks the usage error
• READMEs: run commands updated for the command-plus-args form

How Has This Been Tested?

Locally.

Breaking Changes

N/a

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

Assisted by Claude Code

[Copilot]

🟡 Changes recommended

The Python input reader can hang on non-UTF-8 input, while Go startup cancellation can exit with an error and bypass session cleanup.

2 open issues

• Clean up and exit normally when startup is canceled · New
• Decode stdin using its configured encoding and propagate read errors · New

What changed in this PR

This PR addresses #269 by aligning the five tutorial clients around a common command-plus-arguments launch interface, client identity, and exit behavior.

Changes:

• Standardizes server launching, client metadata, usage errors, and tool caching.
• Adds interrupt handling and aligns API-key environment examples.
• Updates launch documentation and smoke tests, including client-info validation.

File	Description
weather-server-typescript/​README.md	Adds the explicit Node server command.
weather-server-ruby/​README.md	Adds the explicit Ruby server command.
weather-server-python/​README.md	Documents launching the server through uv.
weather-server-go/​README.md	Uses go run . for the client.
tests/​smoke-test.sh	Checks usage errors and updates server launch arguments.
tests/​README.md	Updates the tool-loop test command.
tests/​helpers/​mock-mcp-server.ts	Validates client names and versions.
mcp-client-typescript/​README.md	Documents command-plus-arguments launching.
mcp-client-typescript/​index.ts	Updates launching, client identity, and usage errors.
mcp-client-rust/​src/​main.rs	Adds interrupt handling and background stdin reading.
mcp-client-rust/​.env.example	Adds an empty API-key placeholder.
mcp-client-ruby/​README.md	Documents command-plus-arguments launching.
mcp-client-ruby/​client.rb	Aligns launching, identity, tool caching, and interrupt handling.
mcp-client-python/​README.md	Updates Python and TypeScript server launch examples.
mcp-client-python/​client.py	Aligns launching, identity, caching, and interruptible input.
mcp-client-go/​README.md	Uses go run . in launch examples.
mcp-client-go/​main.go	Adds signal cancellation and updates client metadata.
mcp-client-go/​.env.example	Empties the API-key placeholder.

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

Python’s input thread can raise exceptions during Ctrl-C cleanup, and shared tests lack SIGINT shutdown coverage with stdin kept open at the prompt and during requests across all five clients.

No open issues 🎉

2 previously missed issues

In code that hasn't changed since last review

Guard read callbacks after cancellation or loop shutdown

mcp-client-python/​client.py:230

Ctrl-C cancels the future awaited by read_line, but the daemon thread keeps reading. If stdin then supplies a line or reaches EOF during cleanup, these callbacks emit InvalidStateError; completing the read after the loop closes can also raise RuntimeError. Check line.done() inside the scheduled callback, and ignore completion when the loop has already closed.

Test SIGINT shutdown with open stdin across all clients

mcp-client-rust/​src/​main.rs:500

The shared tool-loop helper exits with quit and never sends SIGINT, leaving the new interrupt handling and pending-input shutdown behavior untested. Add shared scenarios for all five clients that send SIGINT at the prompt with stdin kept open and during a request, then verify timely exit with status 0 and mock-server shutdown. Keeping stdin open is necessary to catch the pending-read hang this change targets.

2 resolved since last review

• Decode stdin using its configured encoding and propagate read errors
• Clean up and exit normally when startup is canceled

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

A blocking Python API call prevents prompt Ctrl-C cancellation and cleanup, while test-helper exit handling and incomplete build checks can hang or prevent the new interrupt tests from running.

2 open issues

• Resolve server exit checks on exit, not stderr close · New
• Include interrupt-test.js in helper build checks · New

1 previously missed issue

In code that hasn't changed since last review

Use async Anthropic requests to allow Ctrl-C cancellation

mcp-client-python/​client.py:274

On Python 3.11+, Ctrl-C cannot promptly stop an in-flight query because process_query() calls synchronous Anthropic.messages.create() on the event-loop thread. A hanging request blocks task cancellation and cleanup, so the new “during a request” interrupt test times out. Use AsyncAnthropic and await the Messages API call so cancellation can stop the request and shut down the MCP server.

_{Review effort: Balanced}

[Copilot]

🔵 Needs a closer look

Human assessment is needed because unpublished findings flag silent cancellation of in-flight queries on stdin closure and conflicting launch instructions.

1 open issue

• Include interrupt-test.js in helper build checks

1 resolved since last review

• Resolve server exit checks on exit, not stderr close

_{Review effort: Balanced}

[Copilot]

🟡 Changes recommended

Ctrl-C in an interactive terminal bypasses the process-only SIGINT listener, leaving in-flight API or tool requests running and delaying cleanup because readline’s SIGINT event is not handled.

2 open issues

• Handle Ctrl-C via readline’s SIGINT event · New
• Include interrupt-test.js in helper build checks

_{Review effort: Balanced}

[a-akimov]

Closing this one, keeping #290 instead