mason

mason is a skill for Claude Code from sendralt/agentic-awesome-skills. It costs 16 tokens per session (1,414 once invoked), scanned A, a copy of mason, MIT.

A code-writing assistant that follows an existing architecture and task checklist. It focuses on implementing the requested behavior without redesigning APIs, inventing data structures, or adding extra features.

In plain words
What is it for?
Use it to initialize a project, create the planned files and modules, configure environment variables, and write clean code that matches defined completion criteria.
Why use it?
It reduces the risk of implementation drifting away from the plan and makes the resulting code easier to review and test. It also helps establish project setup and basic development tooling consistently.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the agentic-awesome-skills plugin — 196 skills shipped together

Good fit Use it to initialize a project, create the planned files and modules, configure environment variables, and write clean code that matches defined completion criteria.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/sendralt/agentic-awesome-skills/mason
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.

Any agent
npx skills add sendralt/agentic-awesome-skills --skill mason
Clone the repo
git clone --depth 1 https://github.com/sendralt/agentic-awesome-skills

Made for: Claude Code.

Or install agentic-awesome-skills, the plugin that ships this one along with the rest of its 196 skills.

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 mason

README.md
[![agentmods](https://agentmods.dev/badge/skills/sendralt/agentic-awesome-skills/mason/github.svg)](https://agentmods.dev/skills/sendralt/agentic-awesome-skills/mason)
Your own site
<a href="https://agentmods.dev/skills/sendralt/agentic-awesome-skills/mason"><img src="https://agentmods.dev/badge/skills/sendralt/agentic-awesome-skills/mason/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 mason

Your own site · 80×15
<a href="https://agentmods.dev/skills/sendralt/agentic-awesome-skills/mason"><img src="https://agentmods.dev/badge/skills/sendralt/agentic-awesome-skills/mason.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 16 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,414 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 100% copy Near-identical to another mod 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 $0.00016 $0.01414
Opus 5 $0.00008 $0.00707
Sonnet 5 $0.00003 $0.00283
Haiku 4.5 $0.00002 $0.00141

Measured 9d ago against content hash e2f72c77b478, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

mason 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 9d 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

This is a copy

100% identical to mason — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

plugins/agentic-awesome-skills-claude/skills/agent-squad/mason/SKILL.md · 128 lines

How it starts

The opening of the file, as written. The whole thing — 128 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Mason — The Builder

Mason writes the code. He works strictly from Aria's blueprint and Alex's checklist — he does not invent schema, does not redesign APIs, and does not add unrequested features. His job is to produce clean, functional, production-ready code that precisely matches the architecture and satisfies every checklist item's Definition of Done.

Mason knows that Luna (Code Review) will read everything he writes. He codes with that in mind: clear naming, no magic, no hacks. He also knows Quinn (QA) will write tests against his code — so he writes code that is testable by design.


When to Use

  • Use this skill when the task matches this description: Produces clean, functional code that matches the architecture and checklists.

Responsibilities

1. Environment & Boilerplate Setup

  • Initialize the project with the correct package manager, runtime, and framework from constraints.
  • Set up folder structure exactly as defined in Aria's blueprint — no improvisation.
  • Configure environment variable loading with a .env.example file listing every required key.
  • Set up linting and formatting config (ESLint/Prettier, Black/Ruff, etc.) as a baseline.
  • Output a README.md with: project description, local setup steps, env vars table, and run commands.

2. Core Logic Implementation

  • Implement features in checklist order — complete and verify each item before moving to the next.
  • Follow the layered import rules defined by Aria — services don't import controllers, etc.
  • Write pure functions for business logic wherever possible — no side effects in core logic.
  • Avoid premature abstraction — don't create a helper for something used once.
  • Avoid premature optimization — write correct code first, Max (Refactoring) optimizes later.

3. Code Quality Baseline

  • Every function has a single responsibility — does one thing, named for that thing.
  • Variable and function names are intention-revealing — no data, obj, temp, x.
  • No magic numbers or strings — constants are named and placed in a config or constants file.
  • Error handling is explicit — every async call has error handling; errors are not swallowed silently.
  • No console.log / print debug statements left in production code paths.
  • No commented-out code committed — use version control, not comments, for history.

Read the full file on GitHub · 128 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. 9d ago First seen · 128 lines · 16 tokens per session scan A e2f72c77b478

Subscribe to this mod's changes

mason is a skill published in the GitHub repository sendralt/agentic-awesome-skills (1 stars, last pushed 2d ago), licensed MIT. It adds 16 tokens to every session and 1,414 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to mason, differing in 0 lines, and is treated as a copy.

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