backend-engineer

backend-engineer is an agent for Claude Code from systemowiec/ai-agents-workspace-starter. It costs 44 tokens per session (314 once invoked), scanned A, original, MIT.

An agent role for building Python backends with FastAPI or Django, including APIs, services, data models, database changes, tests, and background workers.

In plain words
What is it for?
Use it when adding endpoints, services, models, repositories, migrations, tests, workers, or backend bug fixes, followed by the project’s test, lint, documentation, and reporting steps.
Why use it?
It gives the coding agent project-specific rules for where business logic belongs and which files and checks are required. FastAPI and Django are Python frameworks for web applications and APIs.

Agent for Claude Code

Written for Claude Code: installed under .claude/. Also seen: model in frontmatter; mentions AGENTS.md.

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/systemowiec/ai-agents-workspace-starter/backend-engineer
Clone the repo
git clone --depth 1 https://github.com/systemowiec/ai-agents-workspace-starter

Made for: Claude Code.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for backend-engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/systemowiec/ai-agents-workspace-starter/backend-engineer.svg)](https://agentmods.dev/agents/systemowiec/ai-agents-workspace-starter/backend-engineer)
Your own site
<a href="https://agentmods.dev/agents/systemowiec/ai-agents-workspace-starter/backend-engineer"><img src="https://agentmods.dev/badge/agents/systemowiec/ai-agents-workspace-starter/backend-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 44 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 314 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 5.1 $0.00044 $0.00314
Opus 5 $0.00022 $0.00157
Sonnet 5 $0.00009 $0.00063
Haiku 4.5 $0.00004 $0.00031

Measured 5d ago against content hash 7b8e63fc3f47, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

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 5d 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-engineer.md · 36 lines

What it actually says

Read and apply strictly:

  1. .agents/roles/backend-engineer.md - full role definition
  2. .agents/skills/add-endpoint/SKILL.md - endpoint patterns
  3. .agents/skills/database-migration/SKILL.md - migration patterns
  4. .agents/skills/write-python-tests/SKILL.md - test patterns
  5. .agents/rules/global.md - Cardinal Rules
  6. AGENTS.md (root) - global rules
  7. .agents/learnings/gotchas.md - known gotchas

Golden rule

Business logic EXCLUSIVELY in services. NEVER in routers/views, models, schemas/serializers.

Mandatory workflow

BEFORE implementation read workflows/spec-development.md. AFTER implementation run workflows/post-impl-verify.md.

When finished

  1. Run: make test + make lint
  2. Update .agents/context/api-map.md if you changed endpoints
  3. Save report in docs/specs/{layer}/{PREFIX}-NNN/impl-backend-engineer.md
  4. Inform: "Implementation complete. Report ready for review."
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. 5d ago First seen · 36 lines · 44 tokens per session scan A 7b8e63fc3f47

Subscribe to this mod's changes

backend-engineer is an agent published in the GitHub repository systemowiec/ai-agents-workspace-starter (2 stars, last pushed 5mo ago), licensed MIT. It adds 44 tokens to every session and 314 once invoked, about $0.0002 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 2026-08-31.

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