2025-01-24 18:42:52 +00:00
|
|
|
|
# Development Guidelines
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
This document contains critical information about working with this codebase. Follow these guidelines precisely.
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
## Core Development Rules
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
1. Package Management
|
|
|
|
|
|
- ONLY use uv, NEVER pip
|
2026-01-16 15:52:33 +01:00
|
|
|
|
- Installation: `uv add <package>`
|
|
|
|
|
|
- Running tools: `uv run <tool>`
|
|
|
|
|
|
- Upgrading: `uv lock --upgrade-package <package>`
|
2025-01-24 18:42:52 +00:00
|
|
|
|
- FORBIDDEN: `uv pip install`, `@latest` syntax
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
2. Code Quality
|
|
|
|
|
|
- Type hints required for all code
|
|
|
|
|
|
- Public APIs must have docstrings
|
|
|
|
|
|
- Functions must be focused and small
|
|
|
|
|
|
- Follow existing patterns exactly
|
2025-07-09 11:15:14 +01:00
|
|
|
|
- Line length: 120 chars maximum
|
2026-01-30 13:11:27 +01:00
|
|
|
|
- FORBIDDEN: imports inside functions. THEY SHOULD BE AT THE TOP OF THE FILE.
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
3. Testing Requirements
|
2025-05-01 11:42:59 -07:00
|
|
|
|
- Framework: `uv run --frozen pytest`
|
2025-01-24 18:42:52 +00:00
|
|
|
|
- Async testing: use anyio, not asyncio
|
2026-01-16 15:52:33 +01:00
|
|
|
|
- Do not use `Test` prefixed classes, use functions
|
2025-01-24 18:42:52 +00:00
|
|
|
|
- Coverage: test edge cases and errors
|
|
|
|
|
|
- New features require tests
|
|
|
|
|
|
- Bug fixes require regression tests
|
2026-01-20 13:12:07 +01:00
|
|
|
|
- IMPORTANT: The `tests/client/test_client.py` is the most well designed test file. Follow its patterns.
|
|
|
|
|
|
- IMPORTANT: Be minimal, and focus on E2E tests: Use the `mcp.client.Client` whenever possible.
|
2026-03-06 17:24:18 +00:00
|
|
|
|
- Coverage: CI requires 100% (`fail_under = 100`, `branch = true`).
|
2026-03-17 19:53:39 +00:00
|
|
|
|
- Full check: `./scripts/test` (~23s). Runs coverage + `strict-no-cover` on the
|
|
|
|
|
|
default Python. Not identical to CI: CI also runs 3.10–3.14 × {ubuntu, windows},
|
|
|
|
|
|
and some branch-coverage quirks only surface on specific matrix entries.
|
|
|
|
|
|
- Targeted check while iterating (~4s, deterministic):
|
2026-03-06 17:24:18 +00:00
|
|
|
|
|
|
|
|
|
|
```bash
|
|
|
|
|
|
uv run --frozen coverage erase
|
|
|
|
|
|
uv run --frozen coverage run -m pytest tests/path/test_foo.py
|
|
|
|
|
|
uv run --frozen coverage combine
|
|
|
|
|
|
uv run --frozen coverage report --include='src/mcp/path/foo.py' --fail-under=0
|
2026-03-17 19:53:39 +00:00
|
|
|
|
UV_FROZEN=1 uv run --frozen strict-no-cover
|
2026-03-06 17:24:18 +00:00
|
|
|
|
```
|
|
|
|
|
|
|
|
|
|
|
|
Partial runs can't hit 100% (coverage tracks `tests/` too), so `--fail-under=0`
|
2026-03-17 19:53:39 +00:00
|
|
|
|
and `--include` scope the report. `strict-no-cover` has no false positives on
|
|
|
|
|
|
partial runs — if your new test executes a line marked `# pragma: no cover`,
|
|
|
|
|
|
even a single-file run catches it.
|
|
|
|
|
|
- Coverage pragmas:
|
|
|
|
|
|
- `# pragma: no cover` — line is never executed. CI's `strict-no-cover` fails if
|
|
|
|
|
|
it IS executed. When your test starts covering such a line, remove the pragma.
|
|
|
|
|
|
- `# pragma: lax no cover` — excluded from coverage but not checked by
|
|
|
|
|
|
`strict-no-cover`. Use for lines covered on some platforms/versions but not
|
|
|
|
|
|
others.
|
|
|
|
|
|
- `# pragma: no branch` — excludes branch arcs only. coverage.py misreports the
|
|
|
|
|
|
`->exit` arc for nested `async with` on Python 3.11+ (worse on 3.14/Windows).
|
2026-02-18 10:47:02 +00:00
|
|
|
|
- Avoid `anyio.sleep()` with a fixed duration to wait for async operations. Instead:
|
|
|
|
|
|
- Use `anyio.Event` — set it in the callback/handler, `await event.wait()` in the test
|
|
|
|
|
|
- For stream messages, use `await stream.receive()` instead of `sleep()` + `receive_nowait()`
|
|
|
|
|
|
- Exception: `sleep()` is appropriate when testing time-based features (e.g., timeouts)
|
|
|
|
|
|
- Wrap indefinite waits (`event.wait()`, `stream.receive()`) in `anyio.fail_after(5)` to prevent hangs
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2026-02-07 14:12:54 +01:00
|
|
|
|
Test files mirror the source tree: `src/mcp/client/streamable_http.py` → `tests/client/test_streamable_http.py`
|
|
|
|
|
|
Add tests to the existing file for that module.
|
|
|
|
|
|
|
2025-01-24 14:20:42 +00:00
|
|
|
|
- For commits fixing bugs or adding features based on user reports add:
|
2025-07-10 16:43:49 +08:00
|
|
|
|
|
2025-01-24 14:20:42 +00:00
|
|
|
|
```bash
|
|
|
|
|
|
git commit --trailer "Reported-by:<name>"
|
|
|
|
|
|
```
|
2025-07-10 16:43:49 +08:00
|
|
|
|
|
2025-01-24 14:20:42 +00:00
|
|
|
|
Where `<name>` is the name of the user.
|
|
|
|
|
|
|
|
|
|
|
|
- For commits related to a Github issue, add
|
2025-07-10 16:43:49 +08:00
|
|
|
|
|
2025-01-24 14:20:42 +00:00
|
|
|
|
```bash
|
2025-01-24 16:59:58 +00:00
|
|
|
|
git commit --trailer "Github-Issue:#<number>"
|
2025-01-24 14:20:42 +00:00
|
|
|
|
```
|
2025-07-10 16:43:49 +08:00
|
|
|
|
|
2025-01-24 14:20:42 +00:00
|
|
|
|
- NEVER ever mention a `co-authored-by` or similar aspects. In particular, never
|
|
|
|
|
|
mention the tool used to create the commit message or PR.
|
|
|
|
|
|
|
|
|
|
|
|
## Pull Requests
|
|
|
|
|
|
|
|
|
|
|
|
- Create a detailed message of what changed. Focus on the high level description of
|
|
|
|
|
|
the problem it tries to solve, and how it is solved. Don't go into the specifics of the
|
|
|
|
|
|
code unless it adds clarity.
|
|
|
|
|
|
|
|
|
|
|
|
- NEVER ever mention a `co-authored-by` or similar aspects. In particular, never
|
|
|
|
|
|
mention the tool used to create the commit message or PR.
|
|
|
|
|
|
|
2026-01-16 09:54:53 +00:00
|
|
|
|
## Breaking Changes
|
|
|
|
|
|
|
|
|
|
|
|
When making breaking changes, document them in `docs/migration.md`. Include:
|
|
|
|
|
|
|
|
|
|
|
|
- What changed
|
|
|
|
|
|
- Why it changed
|
|
|
|
|
|
- How to migrate existing code
|
|
|
|
|
|
|
|
|
|
|
|
Search for related sections in the migration guide and group related changes together
|
|
|
|
|
|
rather than adding new standalone sections.
|
|
|
|
|
|
|
2025-01-24 14:20:42 +00:00
|
|
|
|
## Python Tools
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
## Code Formatting
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
1. Ruff
|
2025-05-01 11:42:59 -07:00
|
|
|
|
- Format: `uv run --frozen ruff format .`
|
|
|
|
|
|
- Check: `uv run --frozen ruff check .`
|
|
|
|
|
|
- Fix: `uv run --frozen ruff check . --fix`
|
2025-01-24 18:42:52 +00:00
|
|
|
|
- Critical issues:
|
|
|
|
|
|
- Line length (88 chars)
|
|
|
|
|
|
- Import sorting (I001)
|
|
|
|
|
|
- Unused imports
|
|
|
|
|
|
- Line wrapping:
|
|
|
|
|
|
- Strings: use parentheses
|
|
|
|
|
|
- Function calls: multi-line with proper indent
|
2026-01-16 15:52:33 +01:00
|
|
|
|
- Imports: try to use a single line
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
2. Type Checking
|
2025-05-01 11:42:59 -07:00
|
|
|
|
- Tool: `uv run --frozen pyright`
|
2025-01-24 18:42:52 +00:00
|
|
|
|
- Requirements:
|
|
|
|
|
|
- Type narrowing for strings
|
|
|
|
|
|
- Version warnings can be ignored if checks pass
|
2025-01-03 15:57:56 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
3. Pre-commit
|
|
|
|
|
|
- Config: `.pre-commit-config.yaml`
|
|
|
|
|
|
- Runs: on git commit
|
|
|
|
|
|
- Tools: Prettier (YAML/JSON), Ruff (Python)
|
|
|
|
|
|
- Ruff updates:
|
|
|
|
|
|
- Check PyPI versions
|
|
|
|
|
|
- Update config rev
|
|
|
|
|
|
- Commit config first
|
2025-01-03 15:57:56 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
## Error Resolution
|
2025-01-03 15:26:25 +00:00
|
|
|
|
|
2025-01-24 18:42:52 +00:00
|
|
|
|
1. CI Failures
|
|
|
|
|
|
- Fix order:
|
|
|
|
|
|
1. Formatting
|
|
|
|
|
|
2. Type errors
|
|
|
|
|
|
3. Linting
|
|
|
|
|
|
- Type errors:
|
|
|
|
|
|
- Get full line context
|
|
|
|
|
|
- Check Optional types
|
|
|
|
|
|
- Add type narrowing
|
|
|
|
|
|
- Verify function signatures
|
|
|
|
|
|
|
|
|
|
|
|
2. Common Issues
|
|
|
|
|
|
- Line length:
|
|
|
|
|
|
- Break strings with parentheses
|
|
|
|
|
|
- Multi-line function calls
|
|
|
|
|
|
- Split imports
|
|
|
|
|
|
- Types:
|
|
|
|
|
|
- Add None checks
|
|
|
|
|
|
- Narrow string types
|
|
|
|
|
|
- Match existing patterns
|
|
|
|
|
|
|
|
|
|
|
|
3. Best Practices
|
|
|
|
|
|
- Check git status before commits
|
|
|
|
|
|
- Run formatters before type checks
|
|
|
|
|
|
- Keep changes minimal
|
|
|
|
|
|
- Follow existing patterns
|
|
|
|
|
|
- Document public APIs
|
2025-01-24 14:20:42 +00:00
|
|
|
|
- Test thoroughly
|
2025-07-09 11:15:14 +01:00
|
|
|
|
|
|
|
|
|
|
## Exception Handling
|
|
|
|
|
|
|
|
|
|
|
|
- **Always use `logger.exception()` instead of `logger.error()` when catching exceptions**
|
|
|
|
|
|
- Don't include the exception in the message: `logger.exception("Failed")` not `logger.exception(f"Failed: {e}")`
|
|
|
|
|
|
- **Catch specific exceptions** where possible:
|
|
|
|
|
|
- File ops: `except (OSError, PermissionError):`
|
|
|
|
|
|
- JSON: `except json.JSONDecodeError:`
|
|
|
|
|
|
- Network: `except (ConnectionError, TimeoutError):`
|
2026-01-16 15:52:33 +01:00
|
|
|
|
- **FORBIDDEN** `except Exception:` - unless in top-level handlers
|
