diff --git a/AGENTS.md b/AGENTS.md new file mode 100644 index 000000000..969227104 --- /dev/null +++ b/AGENTS.md @@ -0,0 +1,138 @@ +# Development Guidelines + +## Branching Model + + + +- `main` is currently the V2 rework. Breaking changes are expected here — when removing or + replacing an API, delete it outright and document the change in + `docs/migration.md`. Do not add `@deprecated` shims or backward-compat layers + on `main`. +- `v1.x` is the release branch for the current stable line. Backport PRs target + this branch and use a `[v1.x]` title prefix. +- `README.md` is frozen at v1 (a pre-commit hook rejects edits). Edit + `README.v2.md` instead. + +## Package Management + +- ONLY use uv, NEVER pip +- Installation: `uv add ` +- Running tools: `uv run --frozen `. Always pass `--frozen` so uv doesn't + rewrite `uv.lock` as a side effect. +- Cross-version testing: `uv run --frozen --python 3.10 pytest ...` to run + against a specific interpreter (CI covers 3.10–3.14). +- Upgrading: `uv lock --upgrade-package ` +- FORBIDDEN: `uv pip install`, `@latest` syntax +- Don't raise dependency floors for CVEs alone. The `>=` constraint already + lets users upgrade. Only raise a floor when the SDK needs functionality from + the newer version, and don't add SDK code to work around a dependency's + vulnerability. See Kludex/uvicorn#2643 and python-sdk #1552 for reasoning. + +## Code Quality + +- Type hints required for all code +- Public APIs must have docstrings. When a public API raises exceptions a + caller would reasonably catch, document them in a `Raises:` section. Don't + list exceptions from argument validation or programmer error. +- `src/mcp/__init__.py` defines the public API surface via `__all__`. Adding a + symbol there is a deliberate API decision, not a convenience re-export. +- IMPORTANT: All imports go at the top of the file — inline imports hide + dependencies and obscure circular-import bugs. Only exception: when a + top-level import genuinely can't work (lazy-loading optional deps, or + tests that re-import a module). + +## Testing + +- Framework: `uv run --frozen pytest` +- Async testing: use anyio, not asyncio +- Do not use `Test` prefixed classes, use functions +- IMPORTANT: Tests should be fast and deterministic. Prefer in-memory async execution; + reach for threads only when necessary, and subprocesses only as a last resort. +- For end-to-end behavior, an in-memory `Client(server)` is usually the + cleanest approach (see `tests/client/test_client.py` for the canonical + pattern). For narrower changes, testing the function directly is fine. Use + judgment. +- Test files mirror the source tree: `src/mcp/client/stdio.py` → + `tests/client/test_stdio.py`. Add tests to the existing file for that module. +- 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 +- Pytest is configured with `filterwarnings = ["error"]`, so warnings fail + tests. Don't silence warnings from your own code; fix the underlying cause. + Scoped `ignore::` entries for upstream libraries are acceptable in + `pyproject.toml` with a comment explaining why. + +### Coverage + +CI requires 100% (`fail_under = 100`, `branch = true`). + +- Full check: `./scripts/test` (~23s). Runs coverage + `strict-no-cover` on the + default Python. Not identical to CI: CI runs 3.10–3.14 × {ubuntu, windows} + × {locked, lowest-direct}, and some branch-coverage quirks only surface on + specific matrix entries. +- Targeted check while iterating (~4s, deterministic): + + ```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 + # UV_FROZEN=1 propagates --frozen to the uv subprocess strict-no-cover spawns + UV_FROZEN=1 uv run --frozen strict-no-cover + ``` + + Partial runs can't hit 100% (coverage tracks `tests/` too), so `--fail-under=0` + 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. + +Avoid adding new `# pragma: no cover`, `# type: ignore`, or `# noqa` comments. +In tests, use `assert isinstance(x, T)` to narrow types instead of +`# type: ignore`. In library code (`src/`), a `# pragma: no cover` needs very +good reasoning — it usually means a test is missing. Audit before pushing: + +```bash +git diff origin/main... | grep -E '^\+.*(pragma|type: ignore|noqa)' +``` + +What the existing pragmas mean: + +- `# pragma: no cover` — line is never executed. CI's `strict-no-cover` (skipped + on Windows runners) 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). + +## 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. + +## Formatting & Type Checking + +- Format: `uv run --frozen ruff format .` +- Lint: `uv run --frozen ruff check . --fix` +- Type check: `uv run --frozen pyright` +- Pre-commit runs all of the above plus markdownlint, a `uv.lock` consistency + check, and README checks — see `.pre-commit-config.yaml` + +## 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):` +- **FORBIDDEN** `except Exception:` - unless in top-level handlers diff --git a/CLAUDE.md b/CLAUDE.md index 2eee085e1..43c994c2d 100644 --- a/CLAUDE.md +++ b/CLAUDE.md @@ -1,174 +1 @@ -# Development Guidelines - -This document contains critical information about working with this codebase. Follow these guidelines precisely. - -## Core Development Rules - -1. Package Management - - ONLY use uv, NEVER pip - - Installation: `uv add ` - - Running tools: `uv run ` - - Upgrading: `uv lock --upgrade-package ` - - FORBIDDEN: `uv pip install`, `@latest` syntax - -2. Code Quality - - Type hints required for all code - - Public APIs must have docstrings - - Functions must be focused and small - - Follow existing patterns exactly - - Line length: 120 chars maximum - - FORBIDDEN: imports inside functions. THEY SHOULD BE AT THE TOP OF THE FILE. - -3. Testing Requirements - - Framework: `uv run --frozen pytest` - - Async testing: use anyio, not asyncio - - Do not use `Test` prefixed classes, use functions - - Coverage: test edge cases and errors - - New features require tests - - Bug fixes require regression tests - - 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. - - Coverage: CI requires 100% (`fail_under = 100`, `branch = true`). - - 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): - - ```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 - UV_FROZEN=1 uv run --frozen strict-no-cover - ``` - - Partial runs can't hit 100% (coverage tracks `tests/` too), so `--fail-under=0` - 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). - - 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 - -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. - -- For commits fixing bugs or adding features based on user reports add: - - ```bash - git commit --trailer "Reported-by:" - ``` - - Where `` is the name of the user. - -- For commits related to a Github issue, add - - ```bash - git commit --trailer "Github-Issue:#" - ``` - -- 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. - -## 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. - -## Python Tools - -## Code Formatting - -1. Ruff - - Format: `uv run --frozen ruff format .` - - Check: `uv run --frozen ruff check .` - - Fix: `uv run --frozen ruff check . --fix` - - Critical issues: - - Line length (88 chars) - - Import sorting (I001) - - Unused imports - - Line wrapping: - - Strings: use parentheses - - Function calls: multi-line with proper indent - - Imports: try to use a single line - -2. Type Checking - - Tool: `uv run --frozen pyright` - - Requirements: - - Type narrowing for strings - - Version warnings can be ignored if checks pass - -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 - -## Error Resolution - -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 - - Test thoroughly - -## 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):` -- **FORBIDDEN** `except Exception:` - unless in top-level handlers +@AGENTS.md diff --git a/pyproject.toml b/pyproject.toml index be1200cff..a5d2c3d80 100644 --- a/pyproject.toml +++ b/pyproject.toml @@ -185,7 +185,6 @@ filterwarnings = [ # This should be fixed on Uvicorn's side. "ignore::DeprecationWarning:websockets", "ignore:websockets.server.WebSocketServerProtocol is deprecated:DeprecationWarning", - "ignore:Returning str or bytes.*:DeprecationWarning:mcp.server.lowlevel", # pywin32 internal deprecation warning "ignore:getargs.*The 'u' format is deprecated:DeprecationWarning", ]