Atdd Mutate
swingerman/engineer
A skill your agent uses to add a third validation layer to the ATDD workflow — after acceptance tests verify WHAT and unit tests verify HOW, mutation testing verifies the tests actually catch bugs.
Post-development test completion. An agent skill from sd0xdev/sd0x-harness.
$ npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a claude-codeProject install by default; add -g for ~/.claude/skills/.
$ gh skill install sd0xdev/sd0x-harness post-dev-test --agent claude-codeProject scope by default; add --scope user for a personal install. Needs GitHub CLI 2.90.0 or later (public preview).
$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .claude/skills && cp -r skills-src/skills/post-dev-test .claude/skills/post-dev-test && rm -rf skills-srcUse ~/.claude/skills/ instead of .claude/skills for a personal install. The folder must contain SKILL.md.
Claude Code skills documentation · loads skills from .claude/skills/
Install the "post-dev-test" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/post-dev-test into .claude/skills/post-dev-test/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "post-dev-test", then confirm the skill loads.Claude Code copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$skill-installer install https://github.com/sd0xdev/sd0x-harness/tree/main/skills/post-dev-testType this inside Codex. $skill-installer <name> installs a curated skill from openai/skills. The installer writes to $CODEX_HOME/skills (default ~/.codex/skills). Restart Codex if the skill does not show up.
$ npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a codexProject install goes to .agents/skills/; add -g for ~/.codex/skills/.
$ gh skill install sd0xdev/sd0x-harness post-dev-test --agent codexProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .agents/skills && cp -r skills-src/skills/post-dev-test .agents/skills/post-dev-test && rm -rf skills-srcUse ~/.agents/skills/ instead of .agents/skills for a personal install.
Codex skills documentation · loads skills from .agents/skills/
Install the "post-dev-test" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/post-dev-test into .agents/skills/post-dev-test/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "post-dev-test", then confirm the skill loads.Codex copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a cursorProject install goes to .agents/skills/; add -g for ~/.cursor/skills/.
$ gh skill install sd0xdev/sd0x-harness post-dev-test --agent cursorProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .cursor/skills && cp -r skills-src/skills/post-dev-test .cursor/skills/post-dev-test && rm -rf skills-srcUse ~/.cursor/skills/ instead of .cursor/skills for a personal install.
Cursor skills documentation · loads skills from .cursor/skills/, .agents/skills/, .claude/skills/, .codex/skills/
Install the "post-dev-test" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/post-dev-test into .cursor/skills/post-dev-test/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "post-dev-test", then confirm the skill loads.Cursor copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gemini skills install https://github.com/sd0xdev/sd0x-harness.git --path skills/post-dev-test--scope user (default) or --scope workspace; --path is the subfolder of the repo that holds the skill; --consent skips the security confirmation prompt.
$ npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a gemini-cliProject install goes to .agents/skills/; add -g for ~/.gemini/skills/.
$ gh skill install sd0xdev/sd0x-harness post-dev-test --agent gemini-cliProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .gemini/skills && cp -r skills-src/skills/post-dev-test .gemini/skills/post-dev-test && rm -rf skills-srcUse ~/.gemini/skills/ instead of .gemini/skills for a personal install, then run /skills reload.
Gemini CLI skills documentation · loads skills from .gemini/skills/, .agents/skills/
Install the "post-dev-test" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/post-dev-test into .gemini/skills/post-dev-test/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "post-dev-test", then confirm the skill loads.Gemini CLI copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ gh skill install sd0xdev/sd0x-harness post-dev-testInstalls for Copilot at project scope by default; add --scope user for a personal install. Preview a skill first with gh skill preview. Needs GitHub CLI 2.90.0 or later (public preview).
$ npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a github-copilotProject install goes to .agents/skills/; add -g for ~/.copilot/skills/.
$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .github/skills && cp -r skills-src/skills/post-dev-test .github/skills/post-dev-test && rm -rf skills-srcUse ~/.copilot/skills/ instead of .github/skills for a personal install. Commit .github/skills so cloud agent and code review can use it.
GitHub Copilot skills documentation · loads skills from .github/skills/, .claude/skills/, .agents/skills/
Install the "post-dev-test" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/post-dev-test into .github/skills/post-dev-test/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "post-dev-test", then confirm the skill loads.GitHub Copilot copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
$ npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a opencodeOpenCode documents no install command of its own. Project install goes to .agents/skills/; add -g for ~/.config/opencode/skills/.
$ gh skill install sd0xdev/sd0x-harness post-dev-test --agent opencodeProject scope by default (.agents/skills/); add --scope user for a personal install.
$ git clone --depth 1 https://github.com/sd0xdev/sd0x-harness.git skills-src && mkdir -p .opencode/skills && cp -r skills-src/skills/post-dev-test .opencode/skills/post-dev-test && rm -rf skills-srcUse ~/.config/opencode/skills/ instead of .opencode/skills for a personal install.
OpenCode skills documentation · loads skills from .opencode/skills/, .claude/skills/, .agents/skills/
Install the "post-dev-test" agent skill from https://github.com/sd0xdev/sd0x-harness/tree/main/skills/post-dev-test into .opencode/skills/post-dev-test/ in this project. Copy the whole folder (SKILL.md and every file beside it), keep the folder name "post-dev-test", then confirm the skill loads.OpenCode copies the folder itself, the same result as the manual copy. Check what it changed before you commit it.
post-dev-testPost-development test completion. An agent skill from sd0xdev/sd0x-harness.
Post Dev Test is an agent skill from sd0xdev/sd0x-harness. Post-development test completion. Use when: checking test coverage after feature-dev, writing missing integration/e2e tests. Not for: unit test generation (use codex-test-gen), test review (use test-review). Output: test files + coverage report.
Its SKILL.md is about 1.8k tokens, which your agent loads only when the skill is triggered. The skill folder holds 2 other files, including reference files (for example `references/test-patterns.md`).
It sits in Testing & QA, covering Test coverage, End-to-end testing and Unit testing. The repository describes itself as: The harness layer for Claude Code — a reference implementation of harness engineering with hook-enforced dual review, state-machine gates that survive context compaction, and… The licence is MIT.
Read from SKILL.md and the folder at commit c9a2036. It shows what the files ask for, not the result of running them.
Pre-approves these tools, so the agent can use them without asking each time:
ReadGrepGlobWriteBashFrom allowed-tools in the SKILL.md frontmatter.
Shell commands in SKILL.md call:
yarnFrom the folder's file list and the shell code blocks in SKILL.md.
No URLs in SKILL.md. Its commands use yarn, which can reach the network depending on how they are called.
From URLs in SKILL.md, links to its own repository left out.
Names no API keys, tokens, secrets or passwords.
From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.
Post Dev Test loads about 1.8k tokens when it runs, and up to ~3.1k if it reads all its reference files. Until then it costs about 65 tokens; SKILL.md has 199 words of instructions outside code blocks.
Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.
The automated check noted patterns worth knowing about, such as sudo or a known installer.
allowed-tools: Read, Grep, Glob, Write, BashAutomated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.
The full file from sd0xdev/sd0x-harness at commit c9a2036, republished under its MIT licence (© sd0xdev). 199 words, ~1,755 tokens.
.claude/skills/post-dev-test/SKILL.md (or your agent's skills folder). This skill also uses 1 other file; get the full folder from GitHub.Even if test coverage looks complete, tests must be executed whenever there are code changes.
| Scenario | Action |
|---|---|
| Code changes exist | Must execute related integration/e2e |
| Tests exist and are complete | Still execute to confirm no regression |
| Tests missing or insufficient | Write then execute |
| Pure doc/comment changes | Can skip |
Reason: Test coverage does not equal tests passing. Existing tests may fail due to code changes.
/codex-test-gen)/codex-test-review)/feature-dev flow first)┌─────────────────────────────────────────────────────────────────┐
│ Phase 1: Analyze Context │
├─────────────────────────────────────────────────────────────────┤
│ 1. From conversation history: what feature was developed? │
│ 2. Identify involved Service / Provider / Controller │
│ 3. List core flows and API endpoints │
└─────────────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────────────┐
│ Phase 2: Check Existing Test Coverage │
├─────────────────────────────────────────────────────────────────┤
│ 1. Search test/integration/ for related tests │
│ 2. Search test/e2e/ for related tests │
│ 3. Assess coverage gaps │
└─────────────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────────────┐
│ Phase 3: Determine Test Strategy │
├─────────────────────────────────────────────────────────────────┤
│ ┌──────────────┬────────────────────────────────────────────┐ │
│ │ Change Type │ Test Requirement │ │
│ ├──────────────┼────────────────────────────────────────────┤ │
│ │ New API │ Integration test (Controller + Service) │ │
│ │ New Service │ Integration test (Service layer) │ │
│ │ Cross-svc │ E2E test (complete flow) │ │
│ │ DB operation │ Integration test (actual DB) │ │
│ │ External API │ Integration test (mock external) │ │
│ └──────────────┴────────────────────────────────────────────┘ │
└─────────────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────────────┐
│ Phase 4: Write Tests │
├─────────────────────────────────────────────────────────────────┤
│ 1. Reference existing test patterns │
│ 2. Use {FRAMEWORK_MOCK_LIB} createApp / createRequester │
│ 3. Follow TEST_ENV environment variable conventions │
│ 4. Write to corresponding directory │
└─────────────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────────────┐
│ Phase 5: Execute Verification │
├─────────────────────────────────────────────────────────────────┤
│ 1. Execute newly added tests │
│ 2. Confirm passing │
│ 3. Report results │
└─────────────────────────────────────────────────────────────────┘| Type | Directory | Naming | Env Variable |
|---|---|---|---|
| Integration | test/integration/ | *.integration.test.ts or *.test.ts | TEST_ENV=integration |
| E2E | test/e2e/ | *.e2e.test.ts or *.test.ts | TEST_ENV=e2e |
import { Application, Framework } from '{FRAMEWORK_WEB}';
import { close, createApp } from '{FRAMEWORK_MOCK_LIB}';
import { ITestRequester, createRequester } from '../../createRequester';
import { TestEnvironment, onlyIf } from '../../helper/test-env';
const describeIntegration = onlyIf([
TestEnvironment.INTEGRATION,
TestEnvironment.E2E,
]);
describeIntegration('Feature Integration Tests', () => {
let app: Application;
let request: ITestRequester;
beforeAll(async () => {
app = await createApp<Framework>();
request = await createRequester(app);
});
afterAll(async () => {
await close(app);
});
describe('Scenario: ...', () => {
it('should ...', async () => {
// Arrange
// Act
// Assert
});
});
});# Execute single integration test
TEST_ENV=integration yarn jest test/integration/path/to/test.ts
# Execute single e2e test
TEST_ENV=e2e yarn jest test/e2e/path/to/test.tsInput: (User Authentication feature developed in conversation)
Phase 1: Identify ActiveAssetsWeeklyService, ActiveAssetsCacheService involved
Phase 2: Search test/e2e/auth/ -> found missing login test
Phase 3: Decide to write E2E test (cross-service flow)
Phase 4: Write active-assets-weekly.e2e.test.ts
Phase 5: Execute test and verify passingInput: (New API endpoint developed in conversation)
Phase 1: Identify Controller + Service
Phase 2: Search test/integration/controller/ -> no corresponding test
Phase 3: Decide to write Integration test
Phase 4: Write new-feature.integration.test.ts
Phase 5: Execute test and verify passingreferences/test-patterns.md - Existing test pattern reference© sd0xdev, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file
SKILL.md and 1 other file (references) in skills/post-dev-test of sd0xdev/sd0x-harness.
Open the folder on GitHubat commit c9a2036
Post Dev Test next to the 5 skills that share the most tags, products or categories with it. Stars are the repository's; “used in” counts other GitHub owners with a copy.
| Skill | Stars | Used in | Tokens | Auto-check | Licence | Repo updated |
|---|---|---|---|---|---|---|
| Post Dev Test this skillsd0xdev/sd0x-harness | 192 | — | ~1.8k | Automated safety check: Notes | MIT | |
| Atdd Mutateswingerman/engineer | 154 | — | ~2.7k | Automated safety check: Pass | MIT | |
| Test Coverageluongnv89/skills | 131 | — | ~2.5k | Automated safety check: Pass | MIT | |
| Scenario Testingaiskillstore/marketplace | 430 | 1 repos | ~830 | Automated safety check: Pass | None | |
| Test Automationrevfactory/harness-100 | 1.3k | — | ~1.7k | Automated safety check: Pass | Apache-2.0 | |
| Test Specialisttravisjneuman/.claude | 101 | — | ~3.7k | Automated safety check: Pass | MIT |
swingerman/engineer
A skill your agent uses to add a third validation layer to the ATDD workflow — after acceptance tests verify WHAT and unit tests verify HOW, mutation testing verifies the tests actually catch bugs.
luongnv89/skills
Generate unit tests for untested branches and edge cases. An agent skill from luongnv89/skills.
aiskillstore/marketplace
This skill should be used when writing tests, validating features, or needing to verify code works.
revfactory/harness-100
A full test automation pipeline. An agent skill from revfactory/harness-100.
travisjneuman/.claude
Test-writing patterns for JS/TS, Python, Go, and Rust (unit, integration, E2E, visual regression).
novotnyllc/dotnet-artisan
Defines .NET test strategy and implementation patterns across xUnit v3 (Facts, Theories, fixtures, IAsyncLifetime), integration testing (WebApplicationFactory, Testcontainers), Aspire testing…
sd0xdev/sd0x-harness
Write an Architecture Decision Record (ADR) for a feature — Context / Decision / Status / Consequences / Alternatives, filed as docs/features/<feature/adr-<NNN-<title.md with a 3-digit zero-padded…
sd0xdev/sd0x-harness
Load GitHub PR review comments into AI session — analyze, triage, plan.
sd0xdev/sd0x-harness
Change-aware next step advisor. An agent skill from sd0xdev/sd0x-harness.
sd0xdev/sd0x-harness
Obsidian vault integration via official CLI. An agent skill from sd0xdev/sd0x-harness.
sd0xdev/sd0x-harness
Agent-driven workflow orchestration (v1 report-only). An agent skill from sd0xdev/sd0x-harness.
sd0xdev/sd0x-harness
Post friendly review comments to a GitHub PR — prepare locally, preview, then submit as atomic review.
Categories
Post-development test completion. An agent skill from sd0xdev/sd0x-harness. Post Dev Test is an agent skill from sd0xdev/sd0x-harness. Post-development test completion.
Post Dev Test fits situations like: : checking test coverage after feature-dev; writing missing integration/e2e tests.
Run `npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a claude-code`. Or copy the skill folder (skills/post-dev-test in sd0xdev/sd0x-harness) into .claude/skills/post-dev-test in your project. Claude Code loads it when a task matches its description.
Run `npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a codex`. Or copy the skill folder (skills/post-dev-test in sd0xdev/sd0x-harness) into .agents/skills/post-dev-test in your project. Codex loads it when a task matches its description.
Cursor, Gemini CLI, GitHub Copilot and OpenCode also load SKILL.md folders. With the skills CLI, run `npx skills add sd0xdev/sd0x-harness --skill post-dev-test -a cursor` (or -a gemini-cli, github-copilot or opencode for the others). To copy it by hand, put the folder in .cursor/skills/post-dev-test, .gemini/skills/post-dev-test, .github/skills/post-dev-test and .opencode/skills/post-dev-test in your project.
Going by SKILL.md and its folder, Post Dev Test needs the command-line tools its instructions call (yarn). Its frontmatter pre-approves these tools: Read, Grep, Glob, Write, Bash.
SKILL.md contains no URLs. Any network use would come from the scripts or tools the agent runs. This is read from the text; nothing was executed.
Our automated static check of SKILL.md found notes only (pre-approves every shell command (allowed-tools: bash)), nothing it rates as a warning. It is not a guarantee. Review the folder before installing.
Post Dev Test is published under the MIT licence (the repository's licence). It allows redistribution, so the full SKILL.md is shown on this page.
About 1.8k tokens (SKILL.md is roughly 7k characters). Agents keep only the skill's name and description in context until a task matches; then they load SKILL.md in full. Its references folder adds about 1.4k tokens, read only when the agent opens those files.
Skills that share tags, products or a category with Post Dev Test: Atdd Mutate (swingerman/engineer, 154 stars), Test Coverage (luongnv89/skills, 131 stars), Scenario Testing (aiskillstore/marketplace, 430 stars) and Test Automation (revfactory/harness-100, 1.3k stars). The comparison table on this page puts their stars, adoption, token cost, safety result and licence side by side.
sd0xdev (a GitHub user) maintains it in sd0xdev/sd0x-harness, which has 192 GitHub stars. The repository holds 91 skills in this directory. The repository was last updated on October 6, 2026.
Source: sd0xdev/sd0x-harness on GitHub. Facts on this page come from the repository at the commit we read; the author's words are quoted as theirs.