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-builder-bsamiee-parametric-portalgit 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-builder-bsamiee-parametric-portal)<a href="https://agentmods.dev/skills/majiayu000/claude-skill-registry/agent-builder-bsamiee-parametric-portal"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-builder-bsamiee-parametric-portal/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-builder-bsamiee-parametric-portal"><img src="https://agentmods.dev/badge/skills/majiayu000/claude-skill-registry/agent-builder-bsamiee-parametric-portal.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00050 | $0.01823 |
| Opus 5 | $0.00025 | $0.00911 |
| Sonnet 5 | $0.00010 | $0.00365 |
| Haiku 4.5 | $0.00005 | $0.00182 |
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 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.
How it starts
The opening of the file, as written. The whole thing — 157 lines — stays where its author put it; the contents beside it link to each section on GitHub.
[H1][AGENT-BUILDER]
Dictum: Structured frontmatter and scoped tools enable discoverable agents.
Specialized execution contexts for Claude Code subagent delegation. Frontmatter controls discovery and capabilities; markdown body encodes behavior.
Location: .claude/agents/ (project) or ~/.claude/agents/ (user). Higher priority wins: CLI flag > project > user > plugin.
Tasks:
- Read index.md — Reference file listing for navigation.
- Read frontmatter.md — Complete schema (11 fields), triggers, syntax.
- Read prompt.md — Structure patterns, constraint markers.
- Read workflow.md — 5-phase creation process.
- (prose) Load
style-standardsskill — Voice, formatting, constraints. - Execute per workflow — UNDERSTAND, ACQUIRE, RESEARCH, AUTHOR, VALIDATE.
- Validate — Quality gate; see §VALIDATION.
Templates: →agent.template.md — Standard agent scaffold.
[REFERENCE]: index.md — Complete reference file listing.
[1][FRONTMATTER]
Dictum: Metadata enables discovery before load.
---
name: agent-name
description: >-
Capability statement. Use when scenario-1, scenario-2, or scenario-3.
tools: Read, Glob, Grep
model: sonnet
skills:
- style-standards
memory: user
---
| [INDEX] | [FIELD] | [TYPE] | [REQ] | [CONSTRAINT] |
|---|---|---|---|---|
| [1] | name |
string | Yes | Kebab-case, max 64 chars, match filename |
| [2] | description |
string | Yes | Third person, active voice, "Use when" clause |
| [3] | tools |
list | No | Comma-separated allowlist; omit = inherit all |
| [4] | disallowedTools |
list | No | Denylist; removed from inherited/allowed tools |
| [5] | model |
enum | No | haiku, sonnet, opus, inherit |
| [6] | permissionMode |
enum | No | default, acceptEdits, delegate, dontAsk, bypassPermissions, plan |
| [7] | maxTurns |
number | No | Maximum agentic turns before subagent stops |
| [8] | skills |
list | No | Full skill content preloaded at startup |
| [9] | mcpServers |
object | No | MCP servers available to this subagent |
| [10] | hooks |
object | No | Scoped lifecycle hooks (all 14 events supported) |
| [11] | memory |
enum | No | user, project, or local persistent scope |
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 · 157 lines · 50 tokens per session scan A 58b79b911506
agent-builder is a skill published in the GitHub repository majiayu000/claude-skill-registry (604 stars, last pushed yesterday), licensed MIT. It adds 50 tokens to every session and 1,823 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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