Backend engineer
Agent Plugins 1.0.0 compatible
Design contract-first APIs, run safe database migrations, tune queries, build reliable background jobs, and triage production bugs.
Version 1.0.2Updated Oct 20, 2026Source
First time? Install with npm i -g harnesstap
Download as Agent Plugins zipWhat's inside
Skills (6)
api-contract-firstDesign an API endpoint's contract (resources, request and response shapes, errors, pagination, auth, idempotency) before writing handlers. Use when adding or changing an HTTP, RPC, or GraphQL endpoint. Produces a reviewed schema (OpenAPI, protobuf, or GraphQL SDL) and contract tests.api-debuggingDiagnose why an API request fails or returns wrong data, from the client request through middleware, handler, and downstream calls. Use when an endpoint returns an unexpected status, wrong payload, intermittent errors, or high latency in local, staging, or production.background-jobsBuild background jobs and queue consumers that survive retries, duplicates, crashes, and poison messages. Use when adding a job, worker, cron task, or event consumer, or when jobs run twice, get stuck, or silently fail.database-migrationsPlan and write schema and data migrations that deploy without downtime or data loss, using the expand, migrate, contract pattern. Use when adding, renaming, or dropping columns or tables, changing types or constraints, adding indexes on large tables, or backfilling data.prod-bug-triageTriage a production bug or error spike in application code: assess impact, find the faulty change or input, choose mitigate vs fix, and record findings. Use when alerts fire on error rate or latency, users report failures, or an error tracker shows a new issue. Infra rollbacks and capacity belong to devops-engineer.query-performanceFind and fix slow database queries using query plans, indexes, and query shape changes, with measured before and after timings. Use when an endpoint is slow because of the database, a query shows up in slow logs, or an ORM produces N+1 queries.
Rules (3)
api-validationValidate every API input at the boundary.error-handlingHandle errors explicitly and expose safe messages.logging-standardsStructured, useful, and safe logs.
Commands (2)
run-migrationsRun pending database migrations locally or against a named non-production environment, with a status check before and after.seed-stagingLoad synthetic seed data into a local or staging database without touching real user data.
Plugins (5)
feature-dev@claude-plugins-officialsuperpowers@claude-plugins-officialcontext7@claude-plugins-officialandrej-karpathy-skills@karpathy-skillscode-simplifier@claude-plugins-official