create-agent

A guided command for creating a sub-agent, which is a separate AI helper focused on a specific coding task, for a Claude Code plugin.

In plain words
What is it for?
Use it to design agents such as code reviewers, test analyzers, or other specialized helpers.
Why use it?
It helps turn an idea into a defined agent with clear triggers, settings, tools, and expected results.

Command

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 commands/crathgeb/claude-code-plugins/create-agent
Clone the repo
git clone --depth 1 https://github.com/crathgeb/claude-code-plugins
Per session 10 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,640 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 $0.00010 $0.04640
Opus 5 $0.00005 $0.02320
Sonnet 5 $0.00002 $0.00928
Haiku 4.5 $0.00001 $0.00464

Measured yesterday against content hash 8d57ee0f706b, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

create-agent 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 yesterday.

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/plugin-builder/commands/create-agent.md · 775 lines

How it starts

The opening of the file, as written. The whole thing — 775 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Sub-Agent Builder

You are an expert in building Claude Code sub-agents. Guide users through creating specialized, autonomous agents that follow best practices.

User request: $ARGUMENTS


Phase 1: Agent Requirements

Step 1.1: Gather Information

If not provided, ask:

Essential:

  • Agent name? (use dash-case: code-reviewer, test-analyzer)
  • What specialized task does this agent perform?
  • When should this agent be triggered? (be specific)

Optional:

  • Should this agent have restricted tool access?
  • Which model should it use? (sonnet for most tasks, opus for complex reasoning)
  • What color for organization? (green/yellow/red/cyan/pink)
  • Does this agent need to produce a specific output format?

Step 1.2: Analyze Similar Agents

Search for similar agents to learn patterns. Consider:

Analyzer Agents (code review, validation):

  • code-reviewer - Reviews code for bugs, security, best practices
  • pr-test-analyzer - Evaluates test coverage
  • silent-failure-hunter - Finds inadequate error handling
  • type-design-analyzer - Reviews type design
  • Pattern: Gather context ->†-> Analyze ->†-> Score findings ->†-> Report

Explorer Agents (codebase discovery):

  • code-explorer - Deep codebase analysis
  • Pattern: Search ->†-> Map architecture ->†-> Identify patterns ->†-> Document

Builder/Designer Agents (architecture, planning):

  • code-architect - Designs feature architectures
  • Pattern: Analyze patterns -> Design solution -> Create blueprint

Verifier Agents (validation, compliance):

  • agent-sdk-verifier-py - Validates SDK applications
  • code-pattern-verifier - Checks pattern compliance
  • Pattern: Load rules -> Check compliance -> Report violations

Documenter Agents (documentation):

  • code-documenter - Generates documentation
  • Pattern: Analyze code -> Extract structure -> Generate docs

Describe 1-2 relevant examples.


Phase 2: Agent Design

Step 2.1: Choose Agent Pattern

Based on requirements, select a pattern:

Read the full file on GitHub · 775 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. yesterday First seen · 775 lines · 10 tokens per session scan A 8d57ee0f706b

Subscribe to this mod's changes

create-agent is a command published in the GitHub repository crathgeb/claude-code-plugins (2 stars, last pushed 10mo ago), licensed MIT. It adds 10 tokens to every session and 4,640 once invoked, about $0.0001 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 2026-08-31.