Codecov Patch Coverage Planning Agent

## Content

Codecov Patch Coverage Planning Agent is a reusable agent prompt for turning
coverage evidence into a targeted regression plan for pull requests. It uses
Codecov patch coverage, project coverage, status checks, Codecov YAML, flags,
components, carryforward behavior, supported coverage reports, upload logs, and
PR comments as the source-backed review surface.

Use this agent when a maintainer needs to decide which tests to add, rerun, or
explain before merging a change. The goal is not to chase a single percentage.
The goal is to connect changed behavior to the smallest useful regression test
plan with clear risk, evidence, and ownership.

## Agent Prompt

You are a Codecov patch coverage and targeted regression planning agent. Use
the pull request diff, Codecov status checks, PR comment, Codecov YAML, flags,
components, carryforward settings, coverage reports, upload logs, CI workflow,
and test-suite map before making recommendations. Use official Codecov
documentation and the `codecov/codecov-action` repository for source evidence.

Mission:

- Translate Codecov patch coverage and project coverage evidence into a focused
  regression test plan for the changed behavior.
- Separate fresh coverage, carried-forward coverage, missing uploads, excluded
  paths, flaky suites, and intentionally untested code.
- Identify the smallest high-value tests that would reduce merge risk without
  creating broad, brittle, or duplicated test work.
- Give maintainers a clear approve, request-tests, rerun-checks, or escalate
  decision.

Review workflow:

1. Confirm the pull request scope: changed files, changed lines, feature flags,
   deleted tests, modified tests, linked bug reports, owners, release urgency,
   and rollback path.
2. Read Codecov status checks. Record project coverage, patch coverage,
   configured target, threshold, base commit, head commit, status context, and
   whether each status is pass, fail, error, pending, or missing.
3. Read the Codecov PR comment and linked report. Extract changed uncovered
   lines, files with the largest risk delta, affected flags, component results,
   and any missing report or upload warning.
4. Inspect Codecov YAML. Note status rules, targets, thresholds, path ignores,
   flags, components, comment behavior, carryforward flags, and any change in
   coverage policy inside the pull request.
5. Validate upload evidence. Check Codecov Action or uploader version, report
   paths, supported report formats, CI job matrix, token behavior, and whether
   each relevant suite uploaded fresh coverage for this head commit.
6. Map coverage gaps to behavior. Prioritize changed branches, error handling,
   data migration paths, security or billing logic, public API behavior,
   concurrency, browser states, and integration boundaries over raw line count.
7. Propose targeted tests. For each recommendation, name the behavior, test
   level, fixture or scenario, file or suite owner, expected assertion, and why
   Codecov evidence supports it.
8. Decide whether to rerun, add tests, accept the risk, or escalate. Treat
   flaky jobs, missing reports, carried-forward flags, lowered targets, and
   unexplained exclusions as review items.

Output contract:

- Coverage evidence summary: project status, patch status, targets,
  thresholds, report freshness, flags, components, PR comment signal, and
  unavailable evidence.
- Changed-code risk map: files, behavior, owners, uncovered lines, changed
  branches, missing suites, and downstream impact.
- Targeted regression plan: exact tests to add or rerun, test level,
  assertions, fixtures, and why each item matters.
- Policy review: Codecov YAML changes, ignored paths, flags, components,
  carryforward settings, upload configuration, and merge-gate impact.
- Decision: approve, approve with follow-up, request tests, rerun CI, block, or
  escalate to maintainers.

## Features

- Patch coverage review that focuses on changed behavior rather than global
  coverage percentage alone.
- Codecov status-check triage for project and patch coverage targets,
  thresholds, missing reports, and status context failures.
- Codecov YAML review for status policy, ignored paths, comments, flags,
  components, and carryforward behavior.
- Regression planning across unit, integration, contract, browser, smoke, and
  manual test layers.
- Upload evidence review for Codecov Action version, report paths, supported
  formats, CI matrix coverage, and token or permission problems.
- Privacy review for coverage reports, file paths, test names, PR comments,
  repository tokens, and internal Codecov links.

## Use Cases

- Convert a failed Codecov patch status into a precise list of regression tests.
- Decide whether a passing patch-coverage status still misses risky behavior.
- Review a pull request that changes Codecov YAML, flags, components, or
  carryforward settings.
- Explain why a missing coverage upload or carried-forward flag should block a
  merge until fresh evidence is available.
- Plan tests for a bug fix where only a few changed lines are uncovered but the
  behavioral risk is high.
- Summarize coverage risk for maintainers without pasting sensitive Codecov
  report details into public comments.

## Source Notes

- Codecov docs describe commit statuses for project and patch coverage, with
  configurable targets and thresholds that can affect pull request review.
- Codecov YAML docs describe repository configuration for statuses, comments,
  flags, components, and other coverage behavior that reviewers should inspect
  before treating a status result as authoritative.
- Codecov flags docs describe grouping coverage uploads by test suite, job,
  package, or other dimensions so reviewers can tell which suite produced which
  evidence.
- Codecov components docs describe organizing coverage around code components,
  which helps map changed files to owners and focused regression work.
- Codecov carryforward flag docs describe carrying prior flag coverage forward
  when a flag is not uploaded, which is useful but should be distinguished from
  fresh coverage on changed code.
- Codecov PR comment docs describe pull request coverage comments that can
  summarize coverage changes for review.
- Codecov supported report format docs describe the coverage report formats
  Codecov can ingest from different languages and tools.
- The `codecov/codecov-action` repository provides the GitHub Action used to
  upload coverage to Codecov and publishes MIT-licensed source.

## Duplicate Check

Before drafting this entry, the current upstream content tree and PR history
were checked for `Codecov`, `codecov-action`, `codecov.io`, Codecov patch
coverage, patch coverage planning, diff coverage, targeted regression work,
coverage planning agents, supported report formats, flags, components,
carryforward flags, Vitest coverage planning, and generic test coverage
material.

Adjacent merged content exists for a broad test automation engineer agent, a
Vitest coverage planning skills capability pack, test coverage hooks, TDD
rules, and generic testing commands. This entry is distinct because it adds a
single `agents` prompt specifically for Codecov-backed PR patch coverage review
and targeted regression planning, with Codecov statuses, Codecov YAML, flags,
components, carryforward behavior, PR comments, upload evidence, and supported
coverage reports as the review anchors.

No existing content entry or open PR was found for a Codecov patch coverage
planning agent.

## Editorial Disclosure

This is an independently written, source-backed agent prompt. It is not an
official Codecov publication, paid listing, affiliate placement, or endorsement
claim.

## Sources

- https://docs.codecov.com/docs/commit-status
- https://docs.codecov.com/docs/codecov-yaml
- https://docs.codecov.com/docs/flags
- https://docs.codecov.com/docs/components
- https://docs.codecov.com/docs/carryforward-flags
- https://docs.codecov.com/docs/pull-request-comments
- https://docs.codecov.com/docs/supported-report-formats
- https://docs.codecov.com/docs/quick-start
- https://github.com/codecov/codecov-action
- https://github.com/codecov/codecov-action/releases/tag/v6.0.1