Guide · Agent skill
How to use the Regression Suite agent skill (regression-suite)
Updated · written with AI from the project's own documentation and checked against our catalogue data
The regression-suite skill is an agent skill for game projects that use a structured game design document (GDD) workflow. Once installed, it lets your AI agent check whether every fixed bug has a test guarding against its return, and whether the game's critical paths are covered by existing tests. This guide explains what the skill does, how to install it, how to trigger it, and what your project needs before it works well.
Regression SuiteDonchitos/Claude-Code-Game-Studios · MIT Download the skill Quick start
- 1Download the ZIP. Download the regression-suite skill ZIP from this page. It contains the SKILL.md file.
- 2Unzip into a skills folder. Unzip the folder into ~/.claude/skills/ for personal use, or into your project's .claude/skills/ for a single project.
- 3Confirm your project layout. Check that tests/, design/gdd/ with systems-index.md, production/qa/bugs/ and hooks/yaml-helper.sh are present.
- 4Start the agent. Open your project in Claude Code or another compatible agent that has the skill folder installed.
- 5Run a mode. Enter /regression-suite update after a bug fix, audit before a phase gate, or report for a read-only status summary.
- 6Review the output. Read tests/regression-suite.md and the flagged gaps, then decide which regression tests to write yourself.
What is an agent skill, and what does regression-suite do?
An agent skill is a folder containing a SKILL.md file with instructions that an agent such as Claude Code reads when you ask for a matching task. The regression-suite skill gives the agent a specific job: maintain a curated list of tests you already have, so the list reflects the game's critical paths and known failure points.
The skill has three jobs. It reviews bugs marked fixed and checks whether a regression test exists for each one. It compares the game's design documents against existing tests to find critical paths with no coverage. It also flags drift, which happens when new features are added without matching regression coverage. The skill's output is a file at tests/regression-suite.md.
- Reviews closed or fixed bugs and labels each as having or missing a regression test.
- Maps GDD acceptance criteria, formulas and edge cases to existing tests in audit mode.
- Writes or updates tests/regression-suite.md, unless you run the read-only report mode.
- Does not write or run tests itself, according to the visible instructions.
Install the regression-suite skill
Download the skill ZIP from this page. The skill is packaged as a folder containing SKILL.md. Unzip it into one of the following locations, depending on whether you want it for all your projects or one project only.
For a personal install across projects, unzip into ~/.claude/skills/. For a single project, unzip into that project's .claude/skills/ folder. In the Claude apps, you can instead upload the ZIP under Settings → Capabilities → Skills.
- Personal install: ~/.claude/skills/regression-suite/
- Project install: .claude/skills/regression-suite/ inside your project folder
- Claude apps: Settings → Capabilities → Skills, then upload the ZIP
Check your project layout before you start
The skill depends on specific folder paths. The source expects a tests/ folder, a design/gdd/ folder containing the GDDs and a systems index, and a production/qa/ folder containing a bugs subfolder. It also reads configuration through a hooks/yaml-helper.sh script. If these are missing, the skill will mostly report missing files rather than produce a useful status.
The skill's config step calls yaml-helper.sh with the resolve_config option. If no configuration block is found, the source says to fall back to defaults in .claude/docs/config-resolution.md, which is a file the skill references but that you should confirm exists in your project.
- tests/ with unit and integration test folders (and tests/regression/ if you use it)
- design/gdd/ with your game design documents and systems-index.md
- production/qa/bugs/ with bug files that include a Status field
- hooks/yaml-helper.sh available to the skill
Trigger the skill with natural requests
You can invoke the skill with a slash command that takes one of three modes: update, audit or report. You can also ask in plain language, such as asking the agent to check whether recent bug fixes have regression tests. If you give no mode, the skill picks update when a sprint is clearly active, and otherwise asks you which mode to run.
Use update after fixing bugs during a sprint. Use audit for a full comparison of design documents against tests. Use report when you only want a status summary for a sprint review, since it does not write files.
- /regression-suite update: scan bug fixes from this sprint and add missing regression tests to the manifest.
- /regression-suite audit: full audit of GDD critical paths against existing test coverage.
- /regression-suite report: read-only status report with no writes.
/regression-suite updateExamples of what the skill produces
In update mode, the skill looks at completed stories and closed bugs, then checks for a test that references each bug ID or failure scenario. For a bug with no such test, it notes that without the test the bug can silently return in a future sprint, and suggests a file path in the form tests/unit/[system]/[bug-slug]_regression_test.[ext].
In audit mode, each acceptance criterion receives a coverage status: COVERED, PARTIAL, MISSING, or EXEMPT for visual, feel, or UI criteria. Missing coverage for formulas or state machines is elevated to a high-priority gap.
- Bug fixed in the combat system with no test referencing its ID: flagged as MISSING REGRESSION TEST, with a suggested test path.
- Formula in a GDD with no matching unit test: flagged as a high-priority gap.
- Acceptance criterion covered only for the happy path: marked PARTIAL.
Safety notes: scripts and network
The skill runs a script. Its allowed tools include a Bash call that runs yaml-helper.sh with resolve_config, and the skill reads configuration by invoking that script. Read hooks/yaml-helper.sh before installing so you know what it does.
The skill is listed as not using the network. Its write permissions are limited to the tools named in its header, which include Write and Edit. Use report mode if you want to be certain that no files change.
- Runs scripts: yes (yaml-helper.sh, resolve_config only, per the allowed-tools list).
- Uses network: no, according to the listing.
- Writes files in update and audit modes; report mode is read-only.
Tips for getting useful results
Keep bug files in production/qa/bugs/ with a clear Status field, since closed bugs are only detected through that field. Name systems consistently so the skill can match folder paths to GDDs. Run update after each fix and audit before a phase gate.
Remember that the visible instructions are truncated. Later steps, such as the rest of the drift check, are not shown in the source reviewed here, so check the full SKILL.md before relying on it for a formal gate.
- Use consistent system slugs across GDDs, test folders and bug files.
- Run report mode for sprint reviews to avoid unintended edits.
- Read the full SKILL.md, since the visible version is cut off.
What people use it for
- Confirming every bug fixed in a sprint has a test that would catch its return.
- Preparing a phase gate that requires a regression suite at the full qa.level.
- Producing a read-only coverage status for a sprint review.
- Spotting GDD formulas and state machines that have no matching unit tests.
Frequently asked questions
How do I install the regression-suite skill?
Download the skill ZIP from this page and unzip it into ~/.claude/skills/ for personal use, or into your project's .claude/skills/ folder. In the Claude apps, you can upload the ZIP under Settings → Capabilities → Skills.
What does the regression-suite skill require?
It requires Claude Code or a compatible agent with the skill folder installed. Your project needs tests/, design/gdd/, production/qa/ folders and a hooks/yaml-helper.sh script, since the skill reads configuration through that script.
Is regression-suite free and what is its licence?
The listing states the licence is MIT. The source does not state any price, so check the directory page for any cost information.
Does regression-suite write or run tests?
The visible instructions only curate and map existing tests. They do not write or run tests, and the file is truncated, so the full scope should be checked in the complete SKILL.md.
Can I use regression-suite on a non-game project?
Not as intended. The instructions are built around game design documents, systems indexes and QA stages, so projects without that layout will mostly get missing-file reports.
What should I do if the skill reports missing files?
Check that tests/, design/gdd/ with systems-index.md, and production/qa/bugs/ exist in your project with the expected names. If you do not use this layout, the skill is not a good fit.
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Our verdict
Use regression-suite if you run a game project with design documents, a bug-tracking folder and a sprint process, and you want every bug fix backed by a test or a read-only coverage report. Pick something else if your project has no design docs, if you want the agent to write or run tests, or if you need a verified full scope, since the visible instructions are truncated.
Download the skill