patterns

A guide to common mistakes when writing or reviewing natural-language instructions for coding agents, including skills, commands, agents, and hooks.

In plain words
What is it for?
Use it to improve descriptions, add useful examples, review prompts, and check agent instructions for recurring design problems.
Why use it?
It helps make instructions specific and usable instead of vague, oversized, contradictory, or triggered by the wrong requests.

Skill for Claude CodeCodex

Install

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.

agentmods
npx agentmods add skills/xiaolai/nlpm/patterns
Any agent
npx skills add xiaolai/nlpm --skill patterns
Clone the repo
git clone --depth 1 https://github.com/xiaolai/nlpm

Made for: Claude Code, Codex.

Per session 48 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,320 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00048 $0.03320
Opus 5 $0.00024 $0.01660
Sonnet 5 $0.00010 $0.00664
Haiku 4.5 $0.00005 $0.00332

Measured 2d ago against content hash 6102af0fe91f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

patterns 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 2d 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.

codex/skills/patterns/SKILL.md · 316 lines

How it starts

The opening of the file, as written. The whole thing — 316 lines — stays where its author put it; the contents beside it link to each section on GitHub.

NL Programming Patterns

Best practices and anti-patterns for writing NL programming artifacts (Claude Code, Codex CLI, Antigravity). Each pattern includes a rationale and a concrete example. The patterns are tool-agnostic — they describe how to write effective natural-language instructions, not tool-specific schemas. Use this skill when authoring or reviewing skills, agents, commands, rules, or hooks.


Patterns (Use These)

P1: Trigger-Optimized Descriptions (R04)

Write agent and skill descriptions with 3+ specific trigger phrases rather than a single generic one-liner. Claude uses description text to decide when to invoke an agent; richer vocabulary improves recall.

Good:

description: |
  Scores NL artifacts and reports findings. Use this agent when scoring plugin
  artifacts, checking prompts for quality findings, checking command
  completeness, or auditing skill descriptions for vagueness.

Bad:

description: "Analyzes files"

The bad example won't trigger reliably — "analyzes files" matches too broadly and too vaguely.


P2: Example-Driven Agents (R09)

Include 2+ <example> blocks in agent descriptions with realistic Context, user turn, and assistant response. Examples anchor the agent's behavior and dramatically improve triggering consistency.

Minimum structure per example:

<example>
Context: <situation that would trigger this agent>
user: <what the user or command says>
assistant: <what this agent does in response>
</example>

Diverse scenarios: Cover at least one user-direct invocation and one command-as-orchestrator invocation if applicable.


P3: Imperative + Rationale Rules (R03, R21)

Write rules as "Do X because Y" not "Don't do Z". The Pink Elephant effect: telling someone not to think of a pink elephant makes them think of it. Prohibitions without alternatives are hard to follow under inference load.

Good:

**Use `${CLAUDE_PLUGIN_ROOT}` for all intra-plugin file references.**

Because absolute paths break when the plugin is installed by different users
or on different machines, portable path variables ensure the plugin works
everywhere it is installed.

Read the full file on GitHub · 316 lines

Changes

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.

  1. 2d ago First seen · 316 lines · 48 tokens per session scan A 6102af0fe91f

Subscribe to this mod's changes

patterns is a skill published in the GitHub repository xiaolai/nlpm (133 stars, last pushed 2d ago), licensed ISC. It adds 48 tokens to every session and 3,320 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 2026-08-30.

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