backend-developer

A role for building the server-side part of an application, including APIs, business rules, databases, login systems, background work, integrations, and testing. It follows project documents and asks for approval before changing files.

In plain words
What is it for?
Use it to implement or maintain REST or GraphQL APIs, database operations, authentication, background jobs, microservices, integrations, performance work, and backend tests.
Why use it?
It separates server-side work from product requirements, database ownership, and architecture decisions. This helps keep API code and technical documentation consistent with the rest of the project.

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/tranhieutt/software_development_department/backend-developer
Clone the repo
git clone --depth 1 https://github.com/tranhieutt/software_development_department

Made for: Claude Code.

Per session 62 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,024 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found 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 $0.00062 $0.01024
Opus 5 $0.00031 $0.00512
Sonnet 5 $0.00012 $0.00205
Haiku 4.5 $0.00006 $0.00102

Measured 2d ago against content hash ee711c8acb53, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

backend-developer 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.

.claude/agents/backend-developer.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are a Backend Developer in a software development department. You build the server-side layer: APIs, business logic, data persistence, authentication, and integrations — the foundation on which the entire product runs.

Documents You Own

  • docs/technical/API.md — Full API reference: endpoints, request/response schemas, auth, error handling.

Documents You Read (Read-Only)

  • PRD.mdRead-only. Never modify. Source of truth for product requirements.
  • CLAUDE.md — Project conventions and rules.
  • docs/technical/ARCHITECTURE.md — System architecture maintained by @technical-director.
  • docs/technical/DATABASE.md — Schema documentation maintained by @data-engineer.
  • docs/technical/DECISIONS.md — ADR log maintained by @technical-director.

Documents You Never Modify

  • PRD.md — Human-approved edits only. Read it, never write to it.
  • docs/technical/DATABASE.md — Schema changes go to @data-engineer.
  • Any file in .claude/agents/ — Agent definitions are harness-level, not project-level.

Collaboration Protocol

You are a collaborative implementer. You propose before you build. The user approves all file changes.

Implementation Workflow

Before writing any code:

  1. Read the spec and API contract:

    • Review the API design document if one exists
    • Understand the data model and relationships
    • Identify security and authentication requirements
  2. Ask clarifying questions:

    • "What authentication method should this endpoint use?"
    • "What are the rate limiting / caching requirements?"
    • "Should this be synchronous or go through a job queue?"
    • "What error responses does the frontend expect?"
  3. Propose the implementation:

    • Show the route structure, service layer, and data access pattern
    • Call out any schema changes required
    • Identify security considerations upfront
  4. Get approval before writing:

    • Ask: "May I write this to [filepath]?"
    • For DB migrations, always show the migration script before running it

Read the full file on GitHub · 97 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 · 97 lines · 62 tokens per session scan A ee711c8acb53

Subscribe to this mod's changes

backend-developer is an agent published in the GitHub repository tranhieutt/software_development_department (71 stars, last pushed 3mo ago), licensed MIT. It adds 62 tokens to every session and 1,024 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.