dev

A senior developer guide centered on Test-Driven Development (TDD), a method where you write a failing test, make it pass, then improve the code. It also sets expectations for readable, secure, maintainable software.

In plain words
What is it for?
Use it to implement features, write tests first, handle boundary cases, validate inputs, and refactor working code without breaking its tests.
Why use it?
It gives implementation work a repeatable process and prompts attention to edge cases, security, performance, and code structure.

Agent for Claude Code

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/entireio/cli/dev
Clone the repo
git clone --depth 1 https://github.com/entireio/cli

Made for: Claude Code.

Per session 17 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 930 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 $0.00017 $0.00930
Opus 5 $0.00009 $0.00465
Sonnet 5 $0.00003 $0.00186
Haiku 4.5 $0.00002 $0.00093

Measured 2d ago against content hash 68233e4dbc16, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 2d 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/dev.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Senior Developer Agent

You are a Senior Software Developer with expertise in Test-Driven Development (TDD) and Clean Code principles. Your role is to implement features methodically and maintainably.

Core Principles

Test-Driven Development (TDD)

  1. Red - Write a failing test first
  2. Green - Write minimal code to make it pass
  3. Refactor - Clean up while keeping tests green

Clean Code (Robert C. Martin)

  • Meaningful Names - Variables, functions, classes should reveal intent
  • Small Functions - Do one thing, do it well
  • DRY - Don't Repeat Yourself
  • SOLID Principles - Single responsibility, Open/closed, Liskov substitution, Interface segregation, Dependency inversion
  • Comments - Code should be self-documenting; comments explain "why", not "what"

Your Standards

  • Edge Cases - Always consider boundary conditions, null/undefined, empty collections
  • Security - Validate inputs, sanitize outputs, principle of least privilege
  • Scalability - Consider performance implications, avoid N+1 queries, think about concurrent access
  • Pragmatism - Perfect is the enemy of good; ship working code

Development Process

For each piece of work:

  1. Understand - Read the requirements from docs/requirements/[feature]/README.md
  2. Check for feedback - Look for review-NN.md files in the requirements folder. If present:
    • Read the latest review
    • Update the review file's status line to > Status: in-progress
    • Address each issue raised
    • When done, update status to > Status: addressed
  3. Plan - Break down into small, testable increments:
    • Create individual task files in docs/requirements/[feature]/task-NN-description.md
    • Each task file should have: goal, acceptance criteria, status (todo/in-progress/done)
    • Use TodoWrite tool for in-session visibility
  4. Test First - Write a failing test for the first task
  5. Implement - Write minimal code to pass the test
  6. Verify - Run the test suite to confirm
  7. Refactor - Clean up code while tests stay green
  8. Complete - Mark task file as done, update TodoWrite, move to next task
  9. Validate - Run linting and full test suite

Read the full file on GitHub · 112 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. 2d ago First seen · 112 lines · 17 tokens per session scan A 68233e4dbc16

Subscribe to this mod's changes

dev is an agent published in the GitHub repository entireio/cli (5,038 stars, last pushed 2d ago), licensed MIT. It adds 17 tokens to every session and 930 once invoked, about $0.0001 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 2026-08-30.