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 perniemann/pnCore --skill pn-writing-skillsgit clone --depth 1 https://github.com/perniemann/pnCoreWrote 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/perniemann/pncore/pn-writing-skills)<a href="https://agentmods.dev/skills/perniemann/pncore/pn-writing-skills"><img src="https://agentmods.dev/badge/skills/perniemann/pncore/pn-writing-skills/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/perniemann/pncore/pn-writing-skills"><img src="https://agentmods.dev/badge/skills/perniemann/pncore/pn-writing-skills.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 | $0.00040 | $0.01525 |
| Opus 5 | $0.00020 | $0.00763 |
| Sonnet 5 | $0.00008 | $0.00305 |
| Haiku 4.5 | $0.00004 | $0.00153 |
Grade A, and why
pn-writing-skills 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 8d 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 — 159 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Writing skills
When to use
- Creating a new SKILL.md file and want test-driven authoring (scenarios first, content second).
- Editing an existing skill to verify it works as expected before deployment.
- Auditing skill quality: checking retrieval triggers, section completeness, guardrail coverage.
- Teaching someone how to author high-quality pnCore skills.
Overview
Writing skills is test-driven development applied to process documentation.
You write test cases (validation scenarios), watch them fail (baseline behavior), write the skill (documentation), watch tests pass (agents comply), and refactor (close loopholes).
Core principle: If you didn't watch an agent fail without the skill, you don't know if the skill teaches the right thing.
Required background: Understand the pn-tdd skill (RED-GREEN-REFACTOR). This skill adapts TDD to documentation.
What is a skill?
A skill is a reference guide for proven techniques, patterns, or tools. Skills help agents find and apply effective approaches.
Skills are: Reusable techniques, patterns, tools, reference guides.
Skills are NOT: Narratives about how you solved a problem once.
TDD mapping for skills
| TDD concept | Skill creation |
|---|---|
| Test case | Validation scenario |
| Production code | Skill document (SKILL.md) |
| Test fails (RED) | Agent violates rule without skill |
| Test passes (GREEN) | Agent complies with skill present |
| Refactor | Close loopholes while maintaining compliance |
| Write test first | Run baseline scenario before writing skill |
| Watch it fail | Document exact rationalizations agent uses |
| Minimal code | Author SKILL.md addressing those violations |
| Watch it pass | Verify agent now complies |
When to create a skill
Create when:
- Technique wasn't intuitively obvious
- You'd reference this again across projects
- Pattern applies broadly (not project-specific)
- Others would benefit
Don't create for:
- One-off solutions
- Standard practices well-documented elsewhere
- Project-specific conventions (use rules or project docs)
- Mechanical constraints (automate with validation)
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.
- 8d ago First seen · 159 lines · 40 tokens per session scan A 20fd6837fd2a
pn-writing-skills is a skill published in the GitHub repository perniemann/pnCore (0 stars, last pushed 5d ago), licensed MIT. It adds 40 tokens to every session and 1,525 once invoked, about $0.0002 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.
Other skills, from other repositories
workflow-patterns
Use this skill when implementing tasks according to Conductor's TDD workflow, handling phase checkpoints, managing git commits for tasks, or understanding the verification protocol.
taiyi-dev
A software-development stage that implements planned tasks using test-driven development, or TDD: write a failing test, make it pass, then improve the code. It checks the task plan, dependencies, file boundaries, and required completion evidence.
maestro-work
Drive one accepted implementation unit - smallest falsifiable behavior, minimum edits, evidence that names the real falsifier; red tests only inside a Full bundle.
contract
Outcome-driven Cortex function development — declares a behavioral contract before generation begins, enforces evidence-tiered proof before $ship, and defends against the self-oracle evaluation failure mode.
test-driven-development
Rigorous TDD methodology enforcing RED-GREEN-REFACTOR discipline. Use when implementing features or fixing bugs during the implement phase. Tests must be written before production code - no exceptions.
ap-policies
Attach a completion policy gate (shell check or judge-agent rubric) to a session or fan-in group so turn-end only passes when the gate is green, then optionally auto-commit pending human ack. Use when the user says "gate this session on tests passing", "attach a policy", "commit only if tests are green", "judge…