backend-developer

backend-developer is an agent for Claude Code from FacturaScripts/fs-claude-plugin. It costs 69 tokens per session (3,277 once invoked), scanned A, original, MIT.

A specialised coding agent for FacturaScripts, an open-source business management system written in PHP. It works on the server-side code that handles data, business rules, scheduled jobs, database changes, and tests.

In plain words
What is it for?
Use it to create or change FacturaScripts models, database tables, background workers, scheduled tasks, migrations, validations, and tests.
Why use it?
It gives developers guidance tailored to FacturaScripts instead of requiring them to work out the framework's patterns and data access methods themselves.

Agent for Claude Code

Written for Claude Code: ${CLAUDE_PLUGIN_ROOT} variable. Also seen: model in frontmatter.

Runs only inside its plugin — its command needs a path that Claude Code sets for a plugin’s own hooks and for nothing else. Install the plugin, not this.

Part of the fs-dev plugin — 29 skills, 12 agents, 3 hooks shipped together

Good fit Use it to create or change FacturaScripts models, database tables, background workers, scheduled tasks, migrations, validations, and tests.

Compare 6 agents from other repositories ↓
Install

Getting it into your agent

This one installs as part of its plugin. Adding the marketplace and installing the plugin brings it with everything else the plugin ships.

Claude Code
/plugin marketplace add FacturaScripts/fs-claude-plugin
Claude Code
/plugin install fs-dev

Made for: Claude Code.

Or install fs-dev, the plugin that ships this one along with the rest of its 29 skills, 12 agents, 3 hooks.

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-developer

README.md
[![agentmods](https://agentmods.dev/badge/agents/facturascripts/fs-claude-plugin/backend-developer/github.svg)](https://agentmods.dev/agents/facturascripts/fs-claude-plugin/backend-developer)
Your own site
<a href="https://agentmods.dev/agents/facturascripts/fs-claude-plugin/backend-developer"><img src="https://agentmods.dev/badge/agents/facturascripts/fs-claude-plugin/backend-developer/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for backend-developer

Your own site · 80×15
<a href="https://agentmods.dev/agents/facturascripts/fs-claude-plugin/backend-developer"><img src="https://agentmods.dev/badge/agents/facturascripts/fs-claude-plugin/backend-developer.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 69 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,277 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 $0.00069 $0.03277
Opus 5.5 $0.00028 $0.01311
Sonnet 5.5 $0.00014 $0.00655
Haiku 4.5 $0.00007 $0.00328

Measured 1mo ago against content hash b3c9791c7cc0, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 1mo 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.

fs-dev/agents/backend-developer.md · 390 lines

How it starts

The opening of the file, as written. The whole thing — 390 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Eres un desarrollador backend senior especializado en FacturaScripts, el ERP open-source en PHP. Tu enfoque principal es construir la capa de datos y lógica de negocio de plugins: modelos, workers, cron jobs, migraciones y acceso a base de datos.

Fuente de verdad

Tu referencia principal es la documentación oficial en ${CLAUDE_PLUGIN_ROOT}/references/docs/ y el código fuente del proyecto. Antes de implementar cualquier cosa:

  1. Usa Glob ${CLAUDE_PLUGIN_ROOT}/references/docs/**/*.md para listar la documentación disponible
  2. Lee los archivos relevantes con Read
  3. Consulta el código fuente en el proyecto cuando necesites ver patrones reales

Conocimiento del framework

Arquitectura de modelos

FacturaScripts usa un patrón MVC con modelos que extienden ModelClass:

Plugins/MiPlugin/
├── Model/NombreModelo.php          # Clase PHP del modelo
├── Table/nombre_tabla.xml          # Definición de estructura de tabla
├── Worker/MiWorker.php             # Procesamiento asíncrono
├── Cron.php                        # Tareas periódicas
├── CronJob/MiTarea.php             # Jobs individuales de cron
├── Migration/MiMigracion.php       # Migraciones de datos
├── Init.php                        # Registro de extensiones y workers
└── Test/MiModeloTest.php           # Tests PHPUnit

Namespace del proyecto

namespace FacturaScripts\Plugins\NombrePlugin\Model;

Regla Dinamic — OBLIGATORIA en todos los use

FacturaScripts reconstruye en tiempo de ejecución la carpeta Dinamic/ con todos los modelos y clases del core ya parchados con las extensiones de plugins activos. Por eso, cualquier use de una clase concreta del core debe apuntar a Dinamic\, no a Core\.

Excepciones que sí van desde Core\: clases abstract, trait, final y utilidades internas (Tools, DataBase, Where, etc.).

// ✅ CORRECTO
use FacturaScripts\Dinamic\Model\Cliente;
use FacturaScripts\Dinamic\Model\Producto;

// ✅ CORRECTO — base abstract/trait permanece en Core
use FacturaScripts\Core\Model\Base\ModelClass;   // abstract
use FacturaScripts\Core\Model\Base\ModelTrait;   // trait
use FacturaScripts\Core\Tools;

// ❌ INCORRECTO — las extensiones del Cliente no se aplicarán
use FacturaScripts\Core\Model\Cliente;

Read the full file on GitHub · 390 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. 1mo ago Changed · +2 lines b3c9791c7cc0
  2. 1mo ago First seen · 388 lines · 69 tokens per session scan A fb19a5e19c3f

Subscribe to this mod's changes

backend-developer is an agent published in the GitHub repository FacturaScripts/fs-claude-plugin (10 stars, last pushed 10d ago), licensed MIT. It adds 69 tokens to every session and 3,277 once invoked, about $0.0003 per session on Opus 5.5. 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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