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.
npx skills add mike-coulbourn/claude-vibes --skill agent-buildergit clone --depth 1 https://github.com/mike-coulbourn/claude-vibesWrote 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.
[](https://agentmods.dev/skills/mike-coulbourn/claude-vibes/agent-builder)<a href="https://agentmods.dev/skills/mike-coulbourn/claude-vibes/agent-builder"><img src="https://agentmods.dev/badge/skills/mike-coulbourn/claude-vibes/agent-builder/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/skills/mike-coulbourn/claude-vibes/agent-builder"><img src="https://agentmods.dev/badge/skills/mike-coulbourn/claude-vibes/agent-builder.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00054 | $0.03125 |
| Opus 5 | $0.00027 | $0.01563 |
| Sonnet 5 | $0.00011 | $0.00625 |
| Haiku 4.5 | $0.00005 | $0.00313 |
Grade A, and why
agent-builder 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 10d 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.
How it starts
The opening of the file, as written. The whole thing — 476 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Builder
A comprehensive guide for creating custom agents in Claude Code. Agents are specialized AI assistants that run in separate context windows, enabling focused, autonomous task execution.
Quick Reference
YAML Frontmatter Fields
| Field | Required | Description |
|---|---|---|
name |
Yes | Unique identifier (lowercase-with-hyphens) |
description |
Yes | When to invoke — critical for discovery |
tools |
No | Allowed tools (inherits all if omitted) |
model |
No | haiku, sonnet, opus, or inherit |
permissionMode |
No | default, acceptEdits, bypassPermissions, plan |
skills |
No | Auto-load Skills when agent starts |
File Locations
| Scope | Location | Use Case |
|---|---|---|
| Project | .claude/agents/agent-name.md |
Team workflows (git-shared) |
| Personal | ~/.claude/agents/agent-name.md |
Individual use (all projects) |
Common Tool Patterns
# Read-only (safest)
tools: Read, Grep, Glob
# File modification
tools: Read, Write, Edit, Grep, Glob
# Git operations only
tools: Bash(git:*)
# Specific commands
tools: Bash(npm test:*), Bash(npm run:*), Read, Grep
# Full shell (use sparingly)
tools: Bash
Model Selection Guide
| Model | Best For | Tradeoff |
|---|---|---|
haiku |
Quick checks, simple tasks | Fast, cheap, less capable |
sonnet |
Balanced work (default) | Good balance |
opus |
Complex analysis, critical tasks | Most capable, slower, expensive |
inherit |
Consistency with main conversation | Adapts to user's model |
6-Phase Workflow
Phase 1: Requirements Gathering
Use AskUserQuestion to understand what the user needs:
Key Questions:
- What task should this agent handle?
- What expertise/role should it have?
- Who will use it — team or personal?
- What should it be able to do vs NOT do?
- How should it present results?
Example Questions:
What specific task should this agent handle?
├── Code review (quality, security, style)
├── Debugging (error investigation, root cause)
├── Testing (run tests, fix failures)
├── Documentation (generate, verify, update)
└── Other: [describe]
Who will use this agent?
├── Just me (personal: ~/.claude/agents/)
├── My team (project: .claude/agents/)
What ships with it
11 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
- examples/code-quality.md 14 KB
- examples/development-workflow.md 15 KB
- examples/specialized-tasks.md 18 KB
- reference/best-practices.md 11 KB
- reference/syntax-guide.md 9.4 KB
- reference/troubleshooting.md 12 KB
- templates/basic-agent.md 4.7 KB
- templates/production-agent.md 15 KB
- templates/with-model-selection.md 8.4 KB
- templates/with-permissions.md 9.4 KB
- templates/with-tool-restrictions.md 8.7 KB
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.
- 10d ago First seen · 476 lines · 54 tokens per session scan A ff52e0b5cef4
agent-builder is a skill published in the GitHub repository mike-coulbourn/claude-vibes (39 stars, last pushed 8mo ago), licensed MIT. It adds 54 tokens to every session and 3,125 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 2026-08-31.
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