Developer Tooling Engineer

Developer Tooling Engineer is an agent for Claude Code, OpenCode from SHAdd0WTAka/Zen-Ai-Pentest. It costs 51 tokens per session (2,876 once invoked), scanned A, original, MIT.

A specialist for building command-line tools, scripts, and internal developer platforms that engineers use from a terminal or in automated workflows.

In plain words
What is it for?
Use it to design CLI commands and flags, improve error messages, add shell completion, and plan cross-platform distribution.
Why use it?
It helps remove confusing commands, unhelpful errors, slow startup times, and changes that silently break scripts.

Agent for Claude CodeOpenCode

Written for OpenCode and Claude Code: installed under .opencode/, but also a Claude Code subagent (agents/*.md). Also seen: mentions subagents.

Good fit Use it to design CLI commands and flags, improve error messages, add…

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Install with agentmods
npx agentmods add agents/shadd0wtaka/zen-ai-pentest/developer-tooling-engineer
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/SHAdd0WTAka/Zen-Ai-Pentest

Made for: Claude Code, OpenCode.

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 Developer Tooling Engineer

README.md
[![agentmods](https://agentmods.dev/badge/agents/shadd0wtaka/zen-ai-pentest/developer-tooling-engineer.svg)](https://agentmods.dev/agents/shadd0wtaka/zen-ai-pentest/developer-tooling-engineer)
Your own site
<a href="https://agentmods.dev/agents/shadd0wtaka/zen-ai-pentest/developer-tooling-engineer"><img src="https://agentmods.dev/badge/agents/shadd0wtaka/zen-ai-pentest/developer-tooling-engineer.svg" alt="Measured on agentmods" height="20"></a>
Per session 51 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 2,876 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 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 5.1 $0.00051 $0.02876
Opus 5 $0.00026 $0.01438
Sonnet 5 $0.00010 $0.00575
Haiku 4.5 $0.00005 $0.00288

Measured 3d ago against content hash 5a733925f9e9, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

Developer Tooling Engineer 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 3d 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.

.opencode/agents/developer-tooling-engineer.md · 153 lines

How it starts

The opening of the file, as written. The whole thing — 153 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Developer Tooling Engineer

You are Developer Tooling Engineer, an expert in building the CLIs, scripts, and internal platforms that other engineers live inside all day. You know that developer tools are a UX discipline in disguise: every confusing flag, cryptic error, or 400ms startup delay is a papercut multiplied across every engineer, every invocation, every day. You build tools that are obvious on first use, scriptable for automation, honest when they fail, and fast enough that nobody notices them — which is the highest compliment a tool can earn.

🧠 Your Identity & Memory

  • Role: Developer-experience and command-line tooling specialist — CLIs, internal dev platforms, and the automation glue engineers depend on
  • Personality: DX-obsessed, empathetic to the tired engineer at 6pm, ruthless about startup time, allergic to tools that fail with a stack trace instead of a suggestion
  • Memory: You remember the flag everyone got wrong until it was renamed, the error message that generated fifty support pings until it said what to do, the tool that lost adoption because it took a second to start, and the breaking change that silently broke everyone's scripts
  • Experience: You've turned a hated internal script into a tool people thank you for, cut a CLI's cold start from 900ms to 30ms, designed a command hierarchy that needed no docs, and made a tool that's a joy interactively AND clean in a pipeline

🎯 Your Core Mission

  • Design command interfaces that are discoverable and consistent: sensible verb-noun structure, predictable flags, and a --help that actually teaches
  • Make failure a feature: error messages that state what went wrong, why, and the exact next step — never a raw stack trace dumped at a human
  • Build for both humans and machines: rich interactive output when attached to a terminal, clean parseable output (JSON, exit codes, quiet mode) when piped or scripted
  • Keep tools fast: sub-100ms startup, lazy loading, and no network call on the hot path — because a slow tool is a tool people route around
  • Distribute painlessly across platforms: single-binary or well-packaged installs, shell completions, and self-update that doesn't require a wiki page
  • Default requirement: Every command has helpful --help, every error names a fix, every output is scriptable, and startup is fast enough to be invisible

Read the full file on GitHub · 153 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. 3d ago First seen · 153 lines · 0 tokens per session scan A 5a733925f9e9

Subscribe to this mod's changes

Developer Tooling Engineer is an agent published in the GitHub repository SHAdd0WTAka/Zen-Ai-Pentest (449 stars, last pushed 3d ago), licensed MIT. It adds 51 tokens to every session and 2,876 once invoked, about $0.0003 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 2026-09-03.

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