builder

builder is an agent for Claude Code from LonerStayle/js-ralph. It costs 58 tokens per session (1,005 once invoked), scanned A, original, no licence file.

A coding agent that implements one planned item from TREE.md, a file describing the work as a tree of smaller tasks.

In plain words
What is it for?
Use it to build individual planned features or components, test their error cases, run the project's verification script, and commit only after it passes.
Why use it?
It requires tests for each expected exception before implementation and verifies the result before committing, reducing the chance of accepting incomplete work.

Agent for Claude Code

Written for Claude Code: effort in frontmatter.

Part of the js-ralph plugin — 3 skills, 7 commands, 8 agents, 5 hooks shipped together

Good fit Use it to build individual planned features or components, test their error cases, run the project's verification script, and commit only after it passes.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/lonerstayle/js-ralph/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/LonerStayle/js-ralph

Made for: Claude Code.

Or install js-ralph, the plugin that ships this one along with the rest of its 3 skills, 7 commands, 8 agents, 5 hooks.

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 builder

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

Your own site · 80×15
<a href="https://agentmods.dev/agents/lonerstayle/js-ralph/builder"><img src="https://agentmods.dev/badge/agents/lonerstayle/js-ralph/builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 58 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,005 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 unknown 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 $0.00058 $0.01005
Opus 5.5 $0.00023 $0.00402
Sonnet 5.5 $0.00012 $0.00201
Haiku 4.5 $0.00006 $0.00101

Measured 9d ago against content hash 067e4a95b5c8, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

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 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.

agents/builder.md · 59 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

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 · 59 lines · 58 tokens per session scan A 067e4a95b5c8

Subscribe to this mod's changes

builder is an agent published in the GitHub repository LonerStayle/js-ralph (2 stars, last pushed 10d ago), with no licence file. It adds 58 tokens to every session and 1,005 once invoked, about $0.0002 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 2026-09-28.

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