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Checkpoint 3 bridge that turns ACs into Gherkin specs and hands off to the ATDD acceptance pipeline workflow.
Install with Codex or Claude Copy this prompt, paste it into Codex, Claude, or another assistant, and let it review the skill page and install it for you.
Based on SOC occupation classification
Analyze changed code for complex, under-tested functions using CRAP scoring; produce ranked refactor and test recommendations.
Validate strict DAE quality gates after implementation-affecting changes, require machine-readable evidence, and write the quality-gate summary before completion or release.
This skill should be used when the user asks to "run mutation testing", "mutate my code", "kill mutants", "check test quality", "find surviving mutants", "verify test effectiveness with mutations", "run stryker", "run mutmut", "run pitest", "set up mutation testing", "how good are my tests", "are my tests catching bugs", or mentions mutation testing, mutation score, or mutant survival in the context of testing. It adds a third validation layer to the ATDD workflow: after acceptance tests verify WHAT and unit tests verify HOW, mutation testing verifies that tests actually catch bugs.
This skill should be used when the user asks to "build a feature", "implement a feature", "add functionality", "start development", "write acceptance tests", "write specs", "use ATDD", "use TDD with acceptance tests", or begins any feature implementation work. Also available as the atdd plugin's main skill. Enforces the Acceptance Test Driven Development workflow: write Given/When/Then specs before code, generate a project-specific test pipeline, and maintain two test streams.
This skill should be used when the user asks to "build a feature with a team", "use ATDD with agents", "create an ATDD team", "set up a team for ATDD", "orchestrate agents for ATDD", "use team-based development", "coordinate agents for feature development", "run the ATDD workflow with teammates", "add ATDD to my team", "extend my team with ATDD", "join the team with ATDD agents", "add spec-writer and reviewer to the team", or "add ATDD roles to the existing team". It orchestrates a six-phase ATDD workflow — spec writing, spec review, pipeline generation, implementation, refine, verify & harden — spawning a fresh agent per phase so no agent erodes across a long-running feature.
Analyze surviving mutants from a mutation testing run and write targeted unit tests to kill them. Re-runs mutations to confirm kills.
| name | atdd |
| description | Checkpoint 3 bridge that turns ACs into Gherkin specs and hands off to the ATDD acceptance pipeline workflow. |
The DAE pipeline's Checkpoint 3 (Spec) entry point. AC discovery (Checkpoint 2,
discover-acs) decided what behaviors must work; this step formalizes them as
a standard-Gherkin spec.md and generates the project-specific test pipeline.
This skill is a thin bridge: the acceptance workflow itself lives in the
atdd plugin (atdd plugin atdd skill). engineer plugin atdd skill wraps it with the DAE checkpoint
contract — the entry gate in, the handoff out — so the acceptance pipeline is a
first-class checkpoint of the engineer pipeline rather than a separate detour.
Requires the atdd plugin. If it is not installed, tell the user to install
the atdd plugin from the Disciplined Agentic Engineering Codex marketplace and stop.
Checkpoint 3, after discover-acs (Checkpoint 2) has produced an approved
acs.md. Produces spec.md + the feature's .build/ pipeline.
Not for: AC discovery (discover-acs); planning (plan); using the
acceptance workflow outside a DAE feature folder (invoke atdd plugin atdd skill directly).
Verify the prior checkpoint is complete: run
${PLUGIN_ROOT}/scripts/dae_handoff.py <feature-dir> --through 2. On a
non-zero exit, stop and surface the gap to the human.
Verify branch hygiene: run ${PLUGIN_ROOT}/scripts/dae_branch.py <feature-dir>.
On a non-zero exit, stop and surface the message to the human — switch
branches and re-invoke. The check honors the git.manual: true manifest
opt-out.
After the gate passes, show the pipeline breadcrumb: run
${PLUGIN_ROOT}/scripts/dae_progress.py <feature-dir> and present its
output to the human — it shows where this checkpoint sits in the DAE pipeline.
The breadcrumb is advisory: a non-zero exit or a missing progress.md never
blocks the skill. Then create one Codex plan item per workflow step below. See
${PLUGIN_ROOT}/references/progress-indicator.md.
Invoke the atdd plugin atdd skill skill, scoped to this feature: write the feature's
spec.md in standard Gherkin from acs.md, then generate the test pipeline
(the pipeline-builder agent + the portable dae_gherkin.py parser). Present
spec.md to the human for approval — specs are the human's contract.
Emit a summary per ${PLUGIN_ROOT}/references/handoff-summary.md.
checkpoint: 3; the exit_criteria block asserts Checkpoint 3's criteria
(Foundation Design Section 8) — spec.md parses to a valid IR, every AC maps to
≥1 scenario, spec-check passes — each with verified_by and evidence.
recommended_next: "use the engineer plugin's plan skill".
atdd plugin atdd skill — the acceptance workflow this skill bridges to