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 jonathan-vella/apex-accelerator --skill agent-authoringgit clone --depth 1 https://github.com/jonathan-vella/apex-acceleratorWrote 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/jonathan-vella/apex-accelerator/agent-authoring)<a href="https://agentmods.dev/skills/jonathan-vella/apex-accelerator/agent-authoring"><img src="https://agentmods.dev/badge/skills/jonathan-vella/apex-accelerator/agent-authoring.svg" alt="Measured on agentmods" 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 Agent Snooping · line 119 Skill enumerates or reads other installed skills. Access to other skills' SKILL.md files or the skills directory reveals prompt instructions, capabilities, and secrets that should be invisible to peer skills.Fix: Remove all code or instructions that list or read other skills' files or directories. Skills should operate independently; cross-skill access is a privilege escalation.
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 | $0.00092 | $0.01050 |
| Opus 5 | $0.00046 | $0.00525 |
| Sonnet 5 | $0.00018 | $0.00210 |
| Haiku 4.5 | $0.00009 | $0.00105 |
Grade A, and why
agent-authoring 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 4d 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 — 130 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Authoring
Create and restructure Copilot agents without loading extended authoring guidance
into every ordinary agent turn. The thin enforcement layer remains in
agent-authoring.instructions.md.
When To Use This Skill
- Create a new
.agent.mdor.prompt.md. - Restructure an oversized or duplicated agent definition.
- Design handoffs or subagent boundaries.
- Select or upgrade an agent model.
- Audit fixed context cost, tool scope, or prompting structure.
- Investigate an agent validation failure requiring more than a local fix.
Do not load this skill for a routine edit where the thin instruction already states the applicable rule.
Prerequisites
- Read the target file and its nearest analogous agent once.
- Check
.github/skills/workflow-engine/templates/workflow-graph.jsonbefore changing workflow topology. - Check
.github/model-catalog.jsonbefore changing model labels. - Preserve user changes and existing runtime contracts.
Workflow
1. Classify The Change
Choose the smallest applicable path:
| Change | Load |
|---|---|
| Frontmatter field or handoff correction | Agent file structure |
| New agent or major body restructure | Authoring workflow |
| Model assignment or effort policy | Model policy |
| Tool-heavy runtime or fallback behavior | Runtime guardrails |
| Decision capture behavior | Decision logging |
| Vendor-specific prompt audit | ../vendor-prompting/SKILL.md |
Load only the references needed for the selected path.
2. Establish Ownership
Keep each concern in one place:
- Agent body: role, goal, workflow-specific constraints, output, stop rules.
- Instruction: enforceable rules that apply automatically by file type.
- Skill: on-demand domain workflow and decision guidance.
- Reference: detailed examples, rationale, matrices, and troubleshooting.
- Registry or graph: machine-readable inventory and topology.
What ships with it
5 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.
- 4d ago First seen · 130 lines · 92 tokens per session scan A 3675180a7f88
agent-authoring is a skill published in the GitHub repository jonathan-vella/apex-accelerator (50 stars, last pushed yesterday), licensed MIT. It adds 92 tokens to every session and 1,050 once invoked, about $0.0005 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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