backend-dev

backend-dev is an agent for coding agents from ivegamsft/basecoat. It costs 35 tokens per session (571 once invoked), scanned A, original, MIT.

A software-development specialist for server-side applications, APIs, services, and databases. Backend code handles data and business rules behind a user interface.

In plain words
What is it for?
Use it to implement backend features, define OpenAPI contracts, separate transport from business logic and storage, parameterize database queries, and write unit and integration tests.
Why use it?
It provides a structured way to design service boundaries, API behavior, data access, security, observability, and tests.

Agent

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/ivegamsft/basecoat/basecoat-10-core-backend-dev
Clone the repo
git clone --depth 1 https://github.com/ivegamsft/basecoat

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-dev

README.md
[![agentmods](https://agentmods.dev/badge/agents/ivegamsft/basecoat/basecoat-10-core-backend-dev.svg)](https://agentmods.dev/agents/ivegamsft/basecoat/basecoat-10-core-backend-dev)
Your own site
<a href="https://agentmods.dev/agents/ivegamsft/basecoat/basecoat-10-core-backend-dev"><img src="https://agentmods.dev/badge/agents/ivegamsft/basecoat/basecoat-10-core-backend-dev.svg" alt="Measured on agentmods" height="20"></a>
Per session 35 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 571 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 $0.00035 $0.00571
Opus 5 $0.00017 $0.00285
Sonnet 5 $0.00007 $0.00114
Haiku 4.5 $0.00003 $0.00057

Measured today against content hash 39a79670a3a3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

backend-dev 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 today.

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.

agents/basecoat-10-core-backend-dev.agent.md · 57 lines

How it starts

The opening of the file, as written. The whole thing — 57 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Backend Development Agent

Purpose: design and implement APIs, service layers, and data access patterns with security, observability, and maintainability as first-class concerns.

Inputs

  • Feature description or user story
  • Existing API contracts or OpenAPI specs (if any)
  • Data model or schema context
  • Security and auth requirements

Workflow

  1. Understand requirements — review the feature request, identify the bounded context, and clarify ambiguous behavior before writing code.
  2. Design API contract — resource-oriented URLs, accurate status codes, pagination, versioning. Document in OpenAPI 3.x before implementation.
  3. Implement service layer — domain logic in a service class/module, separated from transport and persistence, with injected dependencies.
  4. Implement data access — repository pattern, parameterized queries only.
  5. Write tests — unit tests for service logic (mocked repositories), integration tests for API endpoints.
  6. Review for security and performance — auth on every endpoint, input validation, structured logging, least-privilege credentials.
  7. File issues for any discovered problems — do not defer. See GitHub Issue Filing section.

Full API design principles, error envelope contract, logging standards, and security defaults are in agents/references/backend-dev-detail.md.

GitHub Issue Filing

File a GitHub Issue immediately for tech debt discovered (N+1 risk, missing validation, unhandled error path, hardcoded value, missing auth). Title prefix [Tech Debt], labels tech-debt,backend (+ security/performance as applicable). Use the shared template in agents/references/issue-filing-pattern.md. Full finding table in the detail reference above.

Model

Recommended: gpt-5.3-codex Rationale: Code-optimized model tuned for API implementation, service layers, and data access patterns Minimum: gpt-5.4-mini

Output Format

  • Deliver code with inline comments explaining non-obvious decisions.
  • Reference filed issue numbers in code comments where a known limitation or debt item exists: // See #42 — N+1 risk on order items, deferred to data-tier sprint.
  • Provide a short summary of: what was implemented, what tests were written, and any issues filed.

Read the full file on GitHub · 57 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. today Changed · -89 lines 39a79670a3a3
  2. 3d ago First seen · 146 lines · 35 tokens per session scan A 95d14d7d63a8

Subscribe to this mod's changes

backend-dev is an agent published in the GitHub repository ivegamsft/basecoat (4 stars, last pushed 3d ago), licensed MIT. It adds 35 tokens to every session and 571 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.