command-expert

command-expert is an agent for coding agents from davepoon/buildwithclaude. It costs 30 tokens per session (205 once invoked), scanned A, original, MIT.

A specialist for designing and implementing command-line commands, which let users run tools by typing instructions in a terminal.

In plain words
What is it for?
Use it to specify CLI commands, build argument parsing, validate inputs, write usage examples, handle errors, and plan tests.
Why use it?
It helps make command-line tools predictable and easier to use by defining clear arguments, validation, help text, errors, and edge-case behavior.

Agent

Part of the agents-quality-security plugin — 15 agents shipped together

About the project

davepoon/buildwithclaude is a discovery hub and plugin marketplace for Claude Code extensions, including agents, commands, hooks, skills, plugins, MCP servers, and marketplace collections. Developers use it to browse, search, and find installation instructions for tools that extend Claude-related workflows. Catalogue entries include agents, plugins, commands, and skills from this collection.

davepoon/buildwithclaude · 3,415 stars · on GitHub · buildwithclaude.com

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.

agentmods
npx agentmods add agents/davepoon/buildwithclaude/command-expert
Clone the repo
git clone --depth 1 https://github.com/davepoon/buildwithclaude

Or install agents-quality-security, the plugin that ships this one along with the rest of its 15 agents.

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 command-expert

README.md
[![agentmods](https://agentmods.dev/badge/agents/davepoon/buildwithclaude/command-expert.svg)](https://agentmods.dev/agents/davepoon/buildwithclaude/command-expert)
Your own site
<a href="https://agentmods.dev/agents/davepoon/buildwithclaude/command-expert"><img src="https://agentmods.dev/badge/agents/davepoon/buildwithclaude/command-expert.svg" alt="Measured on agentmods" height="20"></a>
Per session 30 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 205 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00030 $0.00205
Opus 5 $0.00015 $0.00102
Sonnet 5 $0.00006 $0.00041
Haiku 4.5 $0.00003 $0.00020

Measured 2d ago against content hash 8cf034ee3c2e, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-05, from the pricing page.

Security

Grade A, and why

command-expert 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 2d 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.

plugins/agents-quality-security/agents/command-expert.md · 34 lines

What it actually says

You are a CLI command expert specializing in command-line interface design and implementation.

When invoked:

  1. Analyze command requirements and use cases
  2. Design argument structure and options
  3. Implement input validation and error handling
  4. Create help documentation and examples
  5. Optimize for user experience and efficiency
  6. Test edge cases and error scenarios

Process:

  • Define clear command purpose and scope
  • Structure arguments intuitively
  • Use standard CLI conventions
  • Implement comprehensive validation
  • Provide helpful error messages
  • Include progress indicators for long operations

Provide:

  • Complete command specification in markdown
  • Argument parsing implementation
  • Input validation rules
  • Help text and usage examples
  • Error handling strategies
  • Testing scenarios
  • Performance optimization tips

Focus on creating intuitive, reliable CLI commands with excellent user experience.

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. 2d ago First seen · 34 lines · 30 tokens per session scan A 8cf034ee3c2e

Subscribe to this mod's changes

command-expert is an agent published in the GitHub repository davepoon/buildwithclaude (3,415 stars, last pushed yesterday), licensed MIT. It adds 30 tokens to every session and 205 once invoked, about $0.0002 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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