Borrowing it
Nothing to install: this file belongs to CGSOG-JumpStarts/JumpStart-AutoNav. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/CGSOG-JumpStarts/JumpStart-AutoNav/main/.github/skills/agent-customization/SKILL.mdgit clone --depth 1 https://github.com/CGSOG-JumpStarts/JumpStart-AutoNavWrote 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/cgsog-jumpstarts/jumpstart-autonav/agent-customization)<a href="https://agentmods.dev/skills/cgsog-jumpstarts/jumpstart-autonav/agent-customization"><img src="https://agentmods.dev/badge/skills/cgsog-jumpstarts/jumpstart-autonav/agent-customization/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/cgsog-jumpstarts/jumpstart-autonav/agent-customization"><img src="https://agentmods.dev/badge/skills/cgsog-jumpstarts/jumpstart-autonav/agent-customization.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 | $0.00092 | $0.01006 |
| Opus 5 | $0.00046 | $0.00503 |
| Sonnet 5 | $0.00018 | $0.00201 |
| Haiku 4.5 | $0.00009 | $0.00101 |
Grade A, and why
agent-customization 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 12d 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 — 78 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Agent Customization
Decision Flow
| Primitive | When to Use |
|---|---|
| Workspace Instructions | Always-on, applies everywhere in the project |
| File Instructions | Explicit via applyTo patterns, or on-demand via description |
| MCP | Integrates external systems, APIs, or data |
| Hooks | Deterministic shell commands at agent lifecycle points (block tools, auto-format, inject context) |
| Custom Agents | Subagents for context isolation, or multi-stage workflows with tool restrictions |
| Prompts | Single focused task with parameterized inputs |
| Skills | On-demand workflow with bundled assets (scripts/templates) |
Quick Reference
Consult the reference docs for templates, domain examples, advanced frontmatter options, asset organization, anti-patterns, and creation checklists. If the references are not enough, load the official documentation links for each primitive.
| Type | File | Location | Reference |
|---|---|---|---|
| Workspace Instructions | copilot-instructions.md, AGENTS.md |
.github/ or root |
Link |
| File Instructions | *.instructions.md |
.github/instructions/ |
Link |
| Prompts | *.prompt.md |
.github/prompts/ |
Link |
| Hooks | *.json |
.github/hooks/ |
Link |
| Custom Agents | *.agent.md |
.github/agents/ |
Link |
| Skills | SKILL.md |
.github/skills/<name>/, .agents/skills/<name>/, .claude/skills/<name>/ |
Link |
User-level: {{USER_PROMPTS_FOLDER}}/ (*.prompt.md, *.instructions.md, *.agent.md; not skills)
Customizations roam with user's settings sync
Creation Process
If you need to explore or validate patterns in the codebase, use a read-only subagent. If the ask-questions tool is available, use it to interview the user and clarify requirements.
If you are creating or updating an agent and discover the solution also needs a reusable skill, use this skill for the agent customization itself and reference the skill-creator skill for the skill-authoring portion of the work.
What ships with it
6 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.
- 12d ago First seen · 78 lines · 92 tokens per session scan A 7a155505b7fa
agent-customization is a skill published in the GitHub repository CGSOG-JumpStarts/JumpStart-AutoNav (10 stars, last pushed 4mo ago), licensed MIT. It adds 92 tokens to every session and 1,006 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 2026-08-31.
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