Skip jobs whose inputs have not changed

Gate expensive workflows and jobs on the files they consume, keeping required check behavior intact.

Prompt

Evaluate and apply this CI technique to my repository: Skip jobs whose inputs have not changed.

Gate expensive workflows and jobs on the files they consume, keeping required check behavior intact.

Read the technique and its source-backed company examples: https://starsling.dev/ci-playbooks/techniques/skip-unaffected-jobs.md

Inspect this repository’s CI workflows, build and test commands, dependencies, and recent run timings. Identify where this technique applies and explain the expected benefit using this repository’s evidence.
Measure a baseline from recent comparable runs: elapsed time, queue time, runner minutes and failures where available. If data is unavailable, say what cannot be measured.
Compare relevant company approaches, checking prerequisites, platform differences and tradeoffs. Rank applicable options by evidence, fit and measurable opportunity; do not present company results as predictions for this repo.
Recommend the smallest safe change, show what checks and fallback paths remain, and ASK ME WHICH CHANGE TO APPROVE BEFORE EDITING ANY FILES.
Only after approval, work on a new feature branch, make one reversible change, and open a reviewable pull request. Never merge or push to a default or protected branch.
Keep required checks, test coverage, deployment and release behavior intact. Validate the change and compare equivalent runs where possible; report limitations and what should be monitored after merge.

View all playbooks

How companies used this technique

Read what each company changed and follow the original sources.

Skip workflows a change cannot affect

Translated to GitHub Actions

What Anthropic built: Anthropic runs a selected set of tests on each pull request.
Your GitHub Actions version: Path and job-level filters that keep expensive workflows to changes in the files they depend on.

Anthropic runs a selected set of tests on each pull request. In GitHub Actions, path and job-level filters keep expensive workflows to changes in the files they depend on.

Use it when: An expensive workflow runs for unrelated files, or app-specific jobs ignore the dependency graph.
Before applying it: Required checks stay reachable: a changes job with job-level conditions keeps a skipped job reporting success.
GitHub Actions adaptation: Compare the source system with your own workflow before applying this translation.

Start the native matrix when its inputs change

The self-update PR added native updater journeys on macOS arm64, macOS Intel and Linux arm64. A step in the test job diffs the change against its base and sets an output; the native matrix runs when that output is true. When the checkout lacks the base commit, or the run is a manual dispatch, the matrix runs. Linux amd64 runs the complete process suite on every change.

Use it when: An expensive matrix verifies one subsystem and runs on every change to the repository.
Before applying it: The path list must cover every input: source, shared packages, lockfiles and the workflow file itself. Required checks must still report when the matrix skips.

Skip whole jobs only when their inputs are unchanged

Mastra gated AGENTS and peer-dependency validation by relevant inputs and generated workspace matrices from affected packages. Job-level conditions and validated matrices sit on top of trigger-level paths filters.

Use it when: A workflow serves several independent packages or checks with distinct inputs.
Before applying it: Workflow files, shared config, dependency changes and routing-tool changes can affect every target. Keep required status reporting and treat invalid routing artifacts as full coverage.

Skip independent jobs only for proven narrow edits

For modifications to existing top-level pytest modules, Codex Security keeps all five Python jobs and the checks that depend on them, and skips the independent SDK, Windows install, Action and eval jobs. A related change also skips container jobs once it proved those modules sit outside the image's build context.

Across seven earlier PRs that only edited existing pytest modules, the jobs this route skips used 17h29m53s of runner time (139 jobs) Source

Use it when: Edits to existing test modules launch unrelated SDK, packaging or container work.
Before applying it: Independence needs more than path names: added, deleted, renamed, shared-helper and mixed changes run the full set.

Run the platform checks a binding change affects

Checkout Kit replaced its single protocol signal with language-specific binding signals and a shared-input signal. A Kotlin-only binding change now starts the Android consumers, and a schema or generator change still starts every platform.

Merged 2026-08-03; the per-binding signals are on the default branch. Source

Use it when: A monorepo starts every platform job for changes confined to one generated binding.
Before applying it: Shared schemas, generators and lockfiles reach several languages, so they map to every consumer.

Skip platform jobs for documentation-only changes

Checkout Kit keeps one shared filter file with per-platform filters that exclude Markdown files and docs directories, so a docs-only pull request starts none of the platform suites while workflow and filter changes still trigger validation. The same exclusions now live in .ci/changed-file-filters.yml on the default branch. Shopify CLI tried the workflow-level form and restored the tests, because they are required to merge.

Merged 2026-06-26; the exclusions are on the default branch. Source

Use it when: Documentation edits start expensive platform suites that build and test only source code.
Before applying it: A workflow skipped at the trigger never reports its required checks; filter at the job level so the checks still report.

Gate expensive checks on their real inputs

Stripe iOS decides whether SDK or build inputs changed before installing tools and running API or dead-code analysis; build configuration counts as an input even inside example or test directories. Sorbet runs its editor-extension jobs on branches only when the extension changed, and always on master. Stripe React Native skipped its end-to-end workflow for Markdown-only pull requests.

Use it when: Documentation or unrelated changes trigger an expensive, narrowly scoped check.
Before applying it: A whole-workflow path filter can leave a required check pending. An always-present gate that reports a no-work result keeps branch protection intact; include global build inputs in the scope.

How companies used this technique

Skip workflows a change cannot affect

Start the native matrix when its inputs change

Skip whole jobs only when their inputs are unchanged

Skip independent jobs only for proven narrow edits

Run the platform checks a binding change affects

Skip platform jobs for documentation-only changes

Gate expensive checks on their real inputs

Related techniques

Install and build only the workspace packages a job uses

Package once, and build full installers after merge

Reduce the setup floor before increasing shard count

Company Playbooks

Related guides

Cancel superseded CI runs

Build and test only what changed

Filter workflows by changed files

Cut CI queue time