deployment-plan

## Purpose Produce a deployment plan that specifies exactly how, when, and by whom a release is deployed, what criteria determine success or failure, and what steps to take if something goes wrong. **A deployment without a rollback plan is a deployment without a safety net.** This skill ensures every production change is made with eyes open and a clear path back. ## Input **Works best with:** The name of the service being deployed and a description of what is changing. **Also valuable:** Current production environment specs, existing deployment pipeline, known risks or dependencies, SLA requirements. **Example invocation:** `Write a deployment plan for releasing PayFlow v2.4.0 to production. This release includes 3 database migrations (additive only), a new webhook delivery queue worker, and updates to the checkout templates. We use a single production server with PHP-FPM and MySQL. Zero downtime is required.` ## Key Concepts ### Deployment Strategies - **Direct Deploy:** Replace running code in-place. Simple, but brief downtime risk. - **Rolling Deploy:** Update instances one at a time. No downtime. If failure occurs, some instances run old code while others run new. - **Blue-Green:** Maintain two identical environments (Blue = current, Green = new). Switch traffic at load balancer after validation. Zero downtime. Full instant rollback by switching back. - **Canary:** Deploy to small percentage of traffic first (e.g., 5%). Monitor. Gradually increase if metrics hold. ...