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 majiayu000/claude-skill-registry --skill agent-development-brendadeeznuts1111-tier-1380-omegagit clone --depth 1 https://github.com/majiayu000/claude-skill-registryWrote 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/majiayu000/claude-skill-registry/agent-development-brendadeeznuts1111-tier-1380-omega)<a href="https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-development-brendadeeznuts1111-tier-1380-omega"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-development-brendadeeznuts1111-tier-1380-omega/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/majiayu000/claude-skill-registry/agent-development-brendadeeznuts1111-tier-1380-omega"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-development-brendadeeznuts1111-tier-1380-omega.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector warn
SkillSpector: 1 finding, up to medium
These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →
- medium Data Exfiltration · line 131 Data is being sent to an external URL. This could be legitimate telemetry or data exfiltration. Manual review is recommended.Fix: Verify the destination URL is trusted and necessary. Remove or replace with documented APIs. Ensure no secrets, tokens, or PII are transmitted.
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 | $0.00069 | $0.02330 |
| Opus 5 | $0.00034 | $0.01165 |
| Sonnet 5 | $0.00014 | $0.00466 |
| Haiku 4.5 | $0.00007 | $0.00233 |
Grade A, and why
agent-development 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 9d 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.
Copies of this mod
2 near-identical copies found in the catalogue:
- agent-development — 100% identical, 0 lines differ
- agent-development — 92% identical, 60 lines differ
How it starts
The opening of the file, as written. The whole thing — 332 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Development for Claude Code
Build effective custom agents for Claude Code with proper delegation, tool access, and prompt design.
Agent Description Pattern
The description field determines whether Claude will automatically delegate tasks.
Strong Trigger Pattern
---
name: agent-name
description: |
[Role] specialist. MUST BE USED when [specific triggers].
Use PROACTIVELY for [task category].
Keywords: [trigger words]
tools: Read, Write, Edit, Glob, Grep, Bash
model: sonnet
---
Weak vs Strong Descriptions
| Weak (won't auto-delegate) | Strong (auto-delegates) |
|---|---|
| "Analyzes screenshots for issues" | "Visual QA specialist. MUST BE USED when analyzing screenshots. Use PROACTIVELY for visual QA." |
| "Runs Playwright scripts" | "Playwright specialist. MUST BE USED when running Playwright scripts. Use PROACTIVELY for browser automation." |
Key phrases:
- "MUST BE USED when..."
- "Use PROACTIVELY for..."
- Include trigger keywords
Delegation Mechanisms
- Explicit:
Task tool subagent_type: "agent-name"- always works - Automatic: Claude matches task to agent description - requires strong phrasing
Session restart required after creating/modifying agents.
Tool Access Principle
If an agent doesn't need Bash, don't give it Bash.
| Agent needs to... | Give tools | Don't give |
|---|---|---|
| Create files only | Read, Write, Edit, Glob, Grep | Bash |
| Run scripts/CLIs | Read, Write, Edit, Glob, Grep, Bash | — |
| Read/audit only | Read, Glob, Grep | Write, Edit, Bash |
Why? Models default to cat > file << 'EOF' heredocs instead of Write tool. Each bash command requires approval, causing dozens of prompts per agent run.
Allowlist Pattern
Instead of restricting Bash, allowlist safe commands in .claude/settings.json:
{
"permissions": {
"allow": [
"Write", "Edit", "WebFetch(domain:*)",
"Bash(cd *)", "Bash(cp *)", "Bash(mkdir *)", "Bash(ls *)",
"Bash(cat *)", "Bash(head *)", "Bash(tail *)", "Bash(grep *)",
"Bash(diff *)", "Bash(mv *)", "Bash(touch *)", "Bash(file *)"
]
}
}
What ships with it
1 file 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.
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.
- 9d ago First seen · 332 lines · 69 tokens per session scan A 19e71afe7184
agent-development is a skill published in the GitHub repository majiayu000/claude-skill-registry (606 stars, last pushed today), licensed MIT. It adds 69 tokens to every session and 2,330 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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