authentication

authentication is a command for Claude Code from Justdvp/claude-code-templates. It costs 0 tokens per session (3,084 once invoked), scanned A, original, MIT.

A Rails 8 command that generates a built-in user authentication system with password handling, login, logout, signup, sessions, models, controllers, views, and helpers. Authentication checks who a user is before allowing access.

In plain words
What is it for?
Use it to generate authentication for a User or custom model, optionally adding fields such as first and last name.
Why use it?
It provides the basic account and session code needed for user sign-in without requiring an external authentication package for common cases.

Command for Claude Code

Written for Claude Code: installed under .claude/.

Good fit Use it to generate authentication for a User or custom model, optionally…

Compare 6 commands from other repositories ↓
Install with agentmods
npx agentmods add commands/justdvp/claude-code-templates/authentication
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.

Clone the repo
git clone --depth 1 https://github.com/Justdvp/claude-code-templates

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 authentication

README.md
[![agentmods](https://agentmods.dev/badge/commands/justdvp/claude-code-templates/authentication.svg)](https://agentmods.dev/commands/justdvp/claude-code-templates/authentication)
Your own site
<a href="https://agentmods.dev/commands/justdvp/claude-code-templates/authentication"><img src="https://agentmods.dev/badge/commands/justdvp/claude-code-templates/authentication.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 3,084 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 $0.00000 $0.03084
Opus 5 $0.00000 $0.01542
Sonnet 5 $0.00000 $0.00617
Haiku 4.5 $0.00000 $0.00308

Measured 3d ago against content hash 79e72c05cf74, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

authentication 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 3d 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

Copies of this mod

1 near-identical copy found in the catalogue:

cli-tool/templates/ruby/examples/rails-app/.claude/commands/authentication.md · 490 lines

How it starts

The opening of the file, as written. The whole thing — 490 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Rails 8 Native Authentication Generator

Generate Rails 8's built-in authentication system with modern security practices.

Purpose

This command helps you implement Rails 8's new native authentication system, eliminating the need for external gems like Devise for basic authentication needs.

Usage

/authentication

What this command does

  1. Generates authentication models with secure password handling
  2. Creates authentication controllers for login/logout/signup
  3. Adds authentication views with modern styling
  4. Implements session management with security best practices
  5. Sets up authentication helpers for controllers and views

Rails 8 Authentication Generator

# Generate authentication for User model
bin/rails generate authentication User

# Or specify custom model name
bin/rails generate authentication Account

# Generate with custom attributes
bin/rails generate authentication User first_name:string last_name:string

Generated User Model

# app/models/user.rb
class User < ApplicationRecord
  has_secure_password
  
  validates :email, presence: true, uniqueness: true
  validates :password, length: { minimum: 8 }, if: -> { new_record? || !password.blank? }
  
  normalizes :email, with: ->(email) { email.strip.downcase }
  
  before_save :normalize_email
  
  private
  
  def normalize_email
    self.email = email.downcase.strip
  end
end

Authentication Controller

# app/controllers/authentication_controller.rb
class AuthenticationController < ApplicationController
  skip_before_action :authenticate_user!, only: [:new, :create]
  
  def new
    # Login page
  end
  
  def create
    user = User.find_by(email: params[:email])
    
    if user&.authenticate(params[:password])
      login(user)
      redirect_to root_path, notice: 'Logged in successfully'
    else
      flash.now[:alert] = 'Invalid email or password'
      render :new, status: :unprocessable_entity
    end
  end
  
  def destroy
    logout
    redirect_to root_path, notice: 'Logged out successfully'
  end
  
  private
  
  def login(user)
    session[:user_id] = user.id
    @current_user = user
  end
  
  def logout
    session[:user_id] = nil
    @current_user = nil
  end
end

Read the full file on GitHub · 490 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. 3d ago First seen · 490 lines · 0 tokens per session scan A 79e72c05cf74

Subscribe to this mod's changes

authentication is a command published in the GitHub repository Justdvp/claude-code-templates (7 stars, last pushed yesterday), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 3,084 tokens. 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 2026-09-03.