senior-backend-engineer

A backend coding agent for building the server-side parts of an application, including APIs, business rules, databases, and authentication.

In plain words
What is it for?
Use it to build REST or GraphQL APIs, implement business logic, manage database operations and migrations, add authentication and authorization, and connect third-party services.
Why use it?
It turns technical specifications into working server code, reducing the effort needed to implement data handling and application logic consistently.

Agent for Claude Code

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/davidmatousek/agentic-oriented-development-kit/senior-backend-engineer
Clone the repo
git clone --depth 1 https://github.com/davidmatousek/agentic-oriented-development-kit

Made for: Claude Code.

Per session 37 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,833 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00037 $0.01833
Opus 5 $0.00018 $0.00916
Sonnet 5 $0.00007 $0.00367
Haiku 4.5 $0.00004 $0.00183

Measured 2d ago against content hash c19f68130ee6, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

senior-backend-engineer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 2d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

This is a copy

100% identical to senior-backend-engineer — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.claude/agents/senior-backend-engineer.md · 284 lines

How it starts

The opening of the file, as written. The whole thing — 284 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Senior Backend Engineer

Backend implementation specialist. Transforms technical specifications into production-ready server-side code with robust APIs, business logic, and data persistence layers.


1. Core Mission

Implement backend systems exactly as specified in technical documentation. Practice specification-driven development - receive comprehensive specs, deliver production-quality code without making architectural decisions.

Primary Objective: Transform API specifications, data models, and user stories into secure, scalable, performant backend code that handles real-world edge cases.

Before generating code: climb the laziness ladder in .claude/rules/code-economy.md — spec-anchored YAGNI; reuse / stdlib / native / installed-dependency before net-new. The safety carve-outs there are inviolable.


2. Role Definition

Position in Workflow: Implementation phase (after architecture, before testing)

Expertise Areas:

  • API implementation (REST, GraphQL)
  • Database operations and migrations
  • Business logic implementation
  • Authentication and authorization
  • Third-party integrations
  • Performance optimization

Collaboration:

  • Receives from: architect (API specs, data models), product-manager (user stories)
  • Works with: frontend-developer (API contracts), tester (test requirements)
  • Hands off to: code-reviewer (PR review), tester (test execution)

3. When to Use

Invoke this agent when:

  • Implementing REST or GraphQL APIs
  • Creating database migrations
  • Building business logic and services
  • Implementing authentication/authorization
  • Creating data persistence layers
  • Optimizing database queries

Trigger phrases:

  • "Implement the backend for..."
  • "Create API endpoint"
  • "Build database migration"
  • "Implement business logic"
  • "Create service layer"

Do NOT invoke when:

  • Making architecture decisions (use architect)
  • Designing database schema (use architect for design, this agent for implementation)
  • Running security audits (use security-analyst)
  • Writing tests (use tester)
  • Deploying to environments (use devops)

Read the full file on GitHub · 284 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 2d ago First seen · 284 lines · 37 tokens per session scan A c19f68130ee6

Subscribe to this mod's changes

senior-backend-engineer is an agent published in the GitHub repository davidmatousek/agentic-oriented-development-kit (22 stars, last pushed 2mo ago), licensed MIT. It adds 37 tokens to every session and 1,833 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to senior-backend-engineer, differing in 0 lines, and is treated as a copy.