# Contributor handoff — pypa/hatch

> Canonical page: https://codevetter.com/unpack/hatch/agent-handoff

# Contributor handoff — pypa/hatch

Scanned commit 7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0 (2026-09-20). Generated by codevetter codevetter 1.15.0 on 2026-10-02.

Source inspection; upstream code and tests were not executed.

Begin with the two package manifests and hatch.toml, then follow the relevant command through Application and Project before changing a backend or plugin contract. Preserve lazy evaluation, cross-platform filesystem behavior, lifecycle ordering, and backend-specific branches. Tests and CI were inspected, not executed; use their definitions to plan separately authorized validation without treating them as passing evidence. The investigation is bounded, and upstream contribution rules require disclosed AI assistance and informed human review.
- Read pyproject.toml, backend/pyproject.toml, and hatch.toml first: Hatch and Hatchling have separate build bootstraps, and the repository test environment includes backend/ as a workspace member. — [pyproject.toml#L1-L11](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/pyproject.toml#L1-L11) [backend/pyproject.toml#L1-L13](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/backend/pyproject.toml#L1-L13) [hatch.toml#L9-L20](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/hatch.toml#L9-L20)
- For execution changes, read Application.runner_context and Project.prepare_environment together: command handlers populate yielded contexts before preparation, and preparation preserves create/install/lock/sync ordering. — [src/hatch/cli/application.py#L119-L140](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/cli/application.py#L119-L140) [src/hatch/project/core.py#L197-L256](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/project/core.py#L197-L256)
- Preserve lazy imports and platform abstractions: Ruff explicitly permits lazy imports for CLI responsiveness, while Path IDs casefold on Windows/macOS and Platform formats subprocess calls. — [ruff.toml#L9-L14](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/ruff.toml#L9-L14) [src/hatch/utils/fs.py#L37-L52](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/utils/fs.py#L37-L52) [src/hatch/utils/platform.py#L92-L105](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/utils/platform.py#L92-L105)
- Build edits must account for both Hatchling subprocess invocation and alternative-backend helper scripts; backend metadata-only hooks are conditionally defined when PIP_BUILD_TRACKER is absent because build hooks can change dependency metadata. — [src/hatch/cli/build/__init__.py#L165-L208](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/cli/build/__init__.py#L165-L208) [src/hatch/project/frontend/core.py#L30-L76](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/project/frontend/core.py#L30-L76) [backend/src/hatchling/build.py#L86-L101](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/backend/src/hatchling/build.py#L86-L101)
- Read tests/conftest.py before choosing validation: fixtures isolate storage, some backend calls run through mocks, and capability markers control skips. Tests and CI were inspected only, so no pass status is available from this brief. — [tests/conftest.py#L75-L109](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/tests/conftest.py#L75-L109) [tests/conftest.py#L438-L479](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/tests/conftest.py#L438-L479) [tests/conftest.py#L528-L575](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/tests/conftest.py#L528-L575) [.github/workflows/test.yml#L46-L53](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/.github/workflows/test.yml#L46-L53)
- When execution is authorized, repository guidance provides hatch test, hatch test --cover, and hatch check; target test paths can be forwarded through hatch test's variadic arguments before expanding validation. — [docs/community/contributing.md#L29-L60](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/docs/community/contributing.md#L29-L60) [src/hatch/cli/test/__init__.py#L12-L34](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/cli/test/__init__.py#L12-L34) [src/hatch/env/internal/test.py#L18-L23](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/env/internal/test.py#L18-L23)
- Distinguish the type-checking paths: CI invokes the types environment's Mypy script, whereas hatch check types uses the hatch-check-types environment and defaults to Pyrefly; pip locking likewise differs from uv because pip cannot apply locks. — [.github/workflows/test.yml#L46-L53](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/.github/workflows/test.yml#L46-L53) [hatch.toml#L35-L47](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/hatch.toml#L35-L47) [src/hatch/cli/check/types.py#L23-L30](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/cli/check/types.py#L23-L30) [src/hatch/env/lockers/pip.py#L101-L114](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/src/hatch/env/lockers/pip.py#L101-L114)
- Upstream contribution documentation requires disclosure of all AI usage, human understanding of contributed code, and human review/editing of AI-assisted issue or discussion content; its commit/submission instructions do not authorize actions in this read-only investigation. — [docs/community/contributing.md#L3-L17](https://github.com/pypa/hatch/blob/7c26ebeaf8b83f5f0374a2545bb15e36c87db0d0/docs/community/contributing.md#L3-L17)

Every claim links to its cited files at the pinned commit. Citations identify source evidence; they do not establish runtime correctness. Independent CodeVetter scan — not reviewed by upstream maintainers.

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