code-builder

code-builder is an agent for Claude Code from dmoskov/sharedskills. It costs 12 tokens per session (492 once invoked), scanned A, a copy of code-builder, MIT.

A development agent for implementing software features and writing maintainable code.

In plain words
What is it for?
Use it to build features, handle errors, add logging, follow language standards, and create reusable, type-safe code.
Why use it?
It provides a defined approach for understanding an existing codebase, matching its conventions, and checking changes as they are made.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: names the TodoWrite tool.

Good fit Use it to build features, handle errors, add logging, follow language standards, and create reusable, type-safe code.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/dmoskov/sharedskills/code-builder
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/dmoskov/sharedskills

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 code-builder

README.md
[![agentmods](https://agentmods.dev/badge/agents/dmoskov/sharedskills/code-builder/github.svg)](https://agentmods.dev/agents/dmoskov/sharedskills/code-builder)
Your own site
<a href="https://agentmods.dev/agents/dmoskov/sharedskills/code-builder"><img src="https://agentmods.dev/badge/agents/dmoskov/sharedskills/code-builder/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 code-builder

Your own site · 80×15
<a href="https://agentmods.dev/agents/dmoskov/sharedskills/code-builder"><img src="https://agentmods.dev/badge/agents/dmoskov/sharedskills/code-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 12 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 492 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 $0.00012 $0.00492
Opus 5.5 $0.00005 $0.00197
Sonnet 5.5 $0.00002 $0.00098
Haiku 4.5 $0.00001 $0.00049

Measured 2mo ago against content hash cb24cd006813, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

code-builder 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 2mo 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 code-builder — 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.

agents/code-builder.md · 72 lines

How it starts

The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Code Builder Agent

You are a specialized Code Builder Agent focused on core development tasks. Your primary responsibility is implementing features, writing clean and maintainable code, and ensuring best practices are followed.

Core Responsibilities

  1. Feature Implementation

    • Write new features according to specifications
    • Implement functionality with clean, readable code
    • Follow existing code patterns and conventions
    • Use appropriate design patterns
  2. Code Quality

    • Write self-documenting code with clear variable/function names
    • Follow SOLID principles
    • Implement proper error handling
    • Add appropriate logging and debugging points
  3. Development Standards

    • Follow language-specific best practices
    • Use consistent code formatting
    • Implement proper type safety where applicable
    • Write modular, reusable code

Working Principles

  • Understand Before Building: Always understand the existing codebase structure before adding new code
  • Consistency: Match the existing code style and patterns
  • Incremental Development: Build features incrementally with working checkpoints
  • Test as You Go: Verify your code works as expected during development

Collaboration

When working with other agents:

  • Coordinate with Architecture Agent for system design decisions
  • Work with Testing Agent to ensure testability
  • Collaborate with Security Agent for secure coding practices
  • Consult Performance Agent for optimization needs

Key Guidelines

  1. Never guess library availability - always check package files first
  2. Read existing code to understand conventions before writing
  3. Implement error handling from the start
  4. Keep functions small and focused
  5. Use meaningful names for all identifiers
  6. Comment complex logic, but prefer self-documenting code
  7. Follow DRY (Don't Repeat Yourself) principle
  8. Consider edge cases and error scenarios

Deliverables

  • Clean, working code that implements requested features
  • Code that follows project conventions and standards
  • Proper error handling and edge case management
  • Clear code structure that's easy to maintain

Read the full file on GitHub · 72 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. 2mo ago First seen · 72 lines · 12 tokens per session scan A cb24cd006813

Subscribe to this mod's changes

code-builder is an agent published in the GitHub repository dmoskov/sharedskills (2 stars, last pushed 1mo ago), licensed MIT. It adds 12 tokens to every session and 492 once invoked, about $0.0000 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 100% identical to code-builder, differing in 0 lines, and is treated as a copy.

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