builder-qwen3-coder

builder-qwen3-coder is an agent for Claude Code from ruizrica/agent-pi. It costs 29 tokens per session (286 once invoked), scanned A, a copy of builder-gpt-5-1-codex-mini, MIT.

A coding agent focused on implementing requested changes with the Qwen 3 Coder model.

In plain words
What is it for?
Use it to add or change code in an existing project, fix related failures, and report the changes and test results.
Why use it?
It gives implementation work a clear process: follow the existing code style, keep changes focused, handle errors, and check tests and linters when available.

Agent for Claude Code

Written for Claude Code: a Claude Code subagent (agents/*.md). Also seen: model in frontmatter.

Good fit Use it to add or change code in an existing project, fix related failures, and report the changes and test results.

Compare 6 agents from other repositories ↓
Install with agentmods
npx agentmods add agents/ruizrica/agent-pi/builder-qwen3-coder
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/ruizrica/agent-pi

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 builder-qwen3-coder

README.md
[![agentmods](https://agentmods.dev/badge/agents/ruizrica/agent-pi/builder-qwen3-coder.svg)](https://agentmods.dev/agents/ruizrica/agent-pi/builder-qwen3-coder)
Your own site
<a href="https://agentmods.dev/agents/ruizrica/agent-pi/builder-qwen3-coder"><img src="https://agentmods.dev/badge/agents/ruizrica/agent-pi/builder-qwen3-coder.svg" alt="Measured on agentmods" height="20"></a>
Per session 29 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 286 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 81% 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 $0.00029 $0.00286
Opus 5 $0.00015 $0.00143
Sonnet 5 $0.00006 $0.00057
Haiku 4.5 $0.00003 $0.00029

Measured 7d ago against content hash 6330474611d7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

builder-qwen3-coder 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 7d 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

81% identical to builder-gpt-5-1-codex-mini — 6 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/builder-qwen3-coder.md · 39 lines

What it actually says

You are a builder agent. Your job is to implement requested changes thoroughly and correctly.

Role

  • Write clean, minimal code that fits the existing codebase
  • Follow established patterns, naming, and style
  • Handle edge cases and error paths
  • Run tests and fix failures before reporting done
  • Make atomic, focused changes — one logical change per edit

Constraints

  • Do not over-engineer. Prefer simple solutions.
  • Do not introduce new dependencies without justification
  • Preserve existing behavior unless the task explicitly changes it
  • Run linters and tests when available
  • Do NOT include any emojis. Emojis are banned.

Workflow

  1. Understand the plan or request fully
  2. Identify the exact files and locations to change
  3. Implement incrementally — small, verifiable edits
  4. Run tests after each significant change
  5. Summarize what was done and any follow-up needed

Output

  • Show key code changes (not every line if large)
  • Report test results and any failures
  • Note any deviations from the plan and why
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. 7d ago First seen · 39 lines · 29 tokens per session scan A 6330474611d7

Subscribe to this mod's changes

builder-qwen3-coder is an agent published in the GitHub repository ruizrica/agent-pi (267 stars, last pushed 1mo ago), licensed MIT. It adds 29 tokens to every session and 286 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 81% identical to builder-gpt-5-1-codex-mini, differing in 6 lines, and is treated as a copy.

Related

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