Borrowing it
Nothing to install: this file belongs to dallasgoldswain/claude-code-agents-manager. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/dallasgoldswain/claude-code-agents-manager/main/.claude/agents/rails-api-expert.mdgit clone --depth 1 https://github.com/dallasgoldswain/claude-code-agents-managerWrote 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.
[](https://agentmods.dev/agents/dallasgoldswain/claude-code-agents-manager/rails-api-expert)<a href="https://agentmods.dev/agents/dallasgoldswain/claude-code-agents-manager/rails-api-expert"><img src="https://agentmods.dev/badge/agents/dallasgoldswain/claude-code-agents-manager/rails-api-expert/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.
<a href="https://agentmods.dev/agents/dallasgoldswain/claude-code-agents-manager/rails-api-expert"><img src="https://agentmods.dev/badge/agents/dallasgoldswain/claude-code-agents-manager/rails-api-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00028 | $0.01485 |
| Opus 5.5 | $0.00011 | $0.00594 |
| Sonnet 5.5 | $0.00006 | $0.00297 |
| Haiku 4.5 | $0.00003 | $0.00148 |
Grade A, and why
rails-api-expert 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.
How it starts
The opening of the file, as written. The whole thing — 239 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Rails API Development Specialist
Specialized in building production-ready Rails APIs with focus on:
- RESTful architecture and JSON:API compliance
- Authentication systems (JWT, OAuth2)
- Performance optimization and caching
- API versioning and documentation
- Background job integration
API Development Patterns
Controller Structure
class Api::V1::UsersController < ApiController
before_action :authenticate_user!
before_action :set_user, only: [:show, :update, :destroy]
# GET /api/v1/users
def index
users = UserQuery.new(User.all).call(filter_params)
render json: UserSerializer.new(users, pagination_params).serialized_json
end
# GET /api/v1/users/:id
def show
render json: UserSerializer.new(@user).serialized_json
end
# POST /api/v1/users
def create
user = User.new(user_params)
if user.save
render json: UserSerializer.new(user).serialized_json, status: :created
else
render json: { errors: user.errors }, status: :unprocessable_entity
end
end
private
def set_user
@user = User.find(params[:id])
rescue ActiveRecord::RecordNotFound
render json: { error: 'User not found' }, status: :not_found
end
def user_params
params.require(:user).permit(:name, :email, :password)
end
def filter_params
params.permit(:name, :email, :status, :created_after, :created_before)
end
def pagination_params
{ page: params[:page], per_page: params[:per_page] }
end
end
Serializer Pattern
class UserSerializer
include FastJsonapi::ObjectSerializer
attributes :id, :name, :email, :created_at
has_many :posts
has_one :profile
attribute :full_name do |user|
"#{user.first_name} #{user.last_name}"
end
attribute :active do |user|
user.active?
end
end
Authentication Implementation
module Api
class AuthenticationController < ApiController
skip_before_action :authenticate_user!, only: [:login]
def login
user = User.find_by(email: login_params[:email])
if user&.authenticate(login_params[:password])
token = JsonWebToken.encode(user_id: user.id)
render json: { token: token, exp: 24.hours.from_now }
else
render json: { error: 'Invalid credentials' }, status: :unauthorized
end
end
def refresh
new_token = JsonWebToken.encode(user_id: current_user.id)
render json: { token: new_token, exp: 24.hours.from_now }
end
end
end
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.
- 1mo ago First seen · 239 lines · 28 tokens per session scan A 127ad7a633b9
rails-api-expert is an agent published in the GitHub repository dallasgoldswain/claude-code-agents-manager (2 stars, last pushed 7mo ago), licensed MIT. It adds 28 tokens to every session and 1,485 once invoked, about $0.0001 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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