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 agentmods add skills/houarnu166/skillful-agent-system-builder/anthropic-referencenpx skills add houarnu166/skillful-agent-system-builder --skill anthropic-referencegit clone --depth 1 https://github.com/houarnu166/skillful-agent-system-builderWrote 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/houarnu166/skillful-agent-system-builder/anthropic-reference)<a href="https://agentmods.dev/skills/houarnu166/skillful-agent-system-builder/anthropic-reference"><img src="https://agentmods.dev/badge/skills/houarnu166/skillful-agent-system-builder/anthropic-reference.svg" alt="Measured on agentmods" 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 | $0.00073 | $0.00781 |
| Opus 5 | $0.00036 | $0.00391 |
| Sonnet 5 | $0.00015 | $0.00156 |
| Haiku 4.5 | $0.00007 | $0.00078 |
Grade A, and why
anthropic-reference 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 5d 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 — 131 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Anthropic Official Guide Reference
This Skill provides bundled core content from Anthropic official guidelines.
Skills Guide
→ See skills-guide.md for complete reference
Core Rules:
| Field | Constraints |
|---|---|
name |
1-64 chars, lowercase + hyphens, matches directory name |
description |
1-1024 chars, functionality + usage timing |
Progressive Disclosure:
- Metadata (~100 tokens) - Always loaded
- Instructions (< 5000 tokens) - When activated
- Resources - When needed
Subagents Guide
→ See subagents-guide.md for complete reference
Core Fields:
| Field | Description |
|---|---|
name |
Unique identifier in lowercase + hyphens |
description |
Claude auto-delegation trigger |
tools |
Allowed tools list |
model |
haiku/sonnet/opus/inherit |
permissionMode |
Permission mode |
Permission Modes:
default- Standard confirmationacceptEdits- Auto-accept editsplan- Read-onlybypassPermissions- Skip all confirmations (caution)
Naming Rules
→ See naming-rules.md for validation rules
Common Rules:
- 1-64 characters
- Lowercase + numbers + hyphens only
- No hyphen at start/end
- No consecutive hyphens
- No reserved words:
anthropic,claude
Validation:
[[ "$name" =~ ^[a-z][a-z0-9-]*[a-z0-9]$ ]] && [ ${#name} -le 64 ]
Quick Reference
Skill Frontmatter
---
name: skill-name
description: |
What it does. Use when: (1) scenario, (2) scenario.
Triggers: "keyword1", "keyword2"
---
Agent Frontmatter
---
name: agent-name
description: |
Role description.
Trigger: Use when condition.
tools: [Read, Grep, Glob]
model: sonnet
permissionMode: default
---
Validation Scenarios
name Validation
- Lowercase + hyphens only?
- 1-64 characters?
- No hyphen at start/end?
- No consecutive hyphens?
- No reserved words?
- (Skill) Matches directory name?
What ships with it
3 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.
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.
- 5d ago First seen · 131 lines · 73 tokens per session scan A 6310ca0d3d90
anthropic-reference is a skill published in the GitHub repository houarnu166/skillful-agent-system-builder (23 stars, last pushed 6mo ago), licensed MIT. It adds 73 tokens to every session and 781 once invoked, about $0.0004 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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