create-agent

A setup guide for creating configurable software agents, including their identity, behavior, skills, tools, model settings, runtime limits, and optional sub-agents.

In plain words
What is it for?
Use it to create agent.yaml and SOUL.md files, organize agent directories, attach skills and tools, define model and runtime settings, configure delegation, and validate the result.
Why use it?
It gives an agent project a consistent structure and a way to validate that its configuration is complete and usable.

Skill for Claude CodeCodex

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 skills/open-gitagent/opengap/create-agent
Any agent
npx skills add open-gitagent/opengap --skill create-agent
Clone the repo
git clone --depth 1 https://github.com/open-gitagent/opengap

Made for: Claude Code, Codex.

Per session 62 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 759 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 $0.00062 $0.00759
Opus 5 $0.00031 $0.00380
Sonnet 5 $0.00012 $0.00152
Haiku 4.5 $0.00006 $0.00076

Measured 2d ago against content hash ea9009dc8c70, 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 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.

examples/gitagent-helper/skills/create-agent/SKILL.md · 131 lines

How it starts

The opening of the file, as written. The whole thing — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Create & Configure Agents

Quick Start

  1. Create directory structure: mkdir -p my-agent/skills
  2. Write agent.yaml with required fields (see below)
  3. Create SOUL.md with agent identity
  4. Add skills, tools, and knowledge as needed
  5. Validate: opengap validate -d ./my-agent

agent.yaml Reference

Required Fields

spec_version: "0.1.0"
name: my-agent          # Unique identifier
version: 1.0.0          # Semantic version
description: What this agent does

Model Configuration

model:
  preferred: claude-sonnet-4-5-20250929
  fallback:
    - claude-haiku-4-5-20251001
  constraints:
    temperature: 0.2     # 0.0 - 1.0
    max_tokens: 4096
    top_p: 0.9

Skills & Tools

skills:
  - code-review          # Must match directory name in skills/
  - security-audit

tools:
  - lint-check           # Must match filename in tools/ (without .yaml)

Runtime

runtime:
  max_turns: 20          # Max conversation turns
  timeout: 120           # Seconds

Sub-Agents

agents:
  reviewer:
    description: Reviews code quality
    delegation:
      mode: auto
      triggers:
        - "review this"

Writing a Good SOUL.md

A SOUL.md should have these sections:

  • Core Identity — Who is this agent? One clear sentence.
  • Communication Style — How does it talk? (direct, friendly, formal, etc.)
  • Values & Principles — What does it prioritize?
  • Domain Expertise — What does it know?
  • Collaboration Style — How does it work with the user?

Writing RULES.md

Structure as:

  • Must Always — Non-negotiable behaviors
  • Must Never — Hard boundaries
  • Output Constraints — Formatting rules
  • Interaction Boundaries — Scope limits

Adding Skills

Create skills/<name>/SKILL.md:

---
name: my-skill
description: What this skill does
license: MIT
allowed-tools: Read Edit Grep
metadata:
  version: "1.0.0"
---

# Instructions
[Detailed instructions for using this skill]

Read the full file on GitHub · 131 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. 2d ago First seen · 131 lines · 62 tokens per session scan A ea9009dc8c70

Subscribe to this mod's changes

create-agent is a skill published in the GitHub repository open-gitagent/opengap (2,921 stars, last pushed 2mo ago), licensed MIT. It adds 62 tokens to every session and 759 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 2026-08-30.

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