# workers-best-practices

Audits Cloudflare Workers code and wrangler.jsonc against official Cloudflare practices. Forces the agent to pull fresh documentation rather than rely on training memory.

- skill · `type=skill` · Codex, ChatGPT · 1 install · ★ 7604
- Author: Cloudflare · official OpenAI repository
- License: MIT · policy=mirror · the beginning of the file is at the end of this page
- Source: https://github.com/openai/plugins/tree/HEAD/plugins/cloudflare/skills/workers-best-practices/SKILL.md
- Updated: 2026-10-08
- HTML: https://affpapa.org/en/nevibecode/skills/workers-best-practices

## What it does

The skill instructs the agent to fetch the latest `@cloudflare/workers-types` package and current Cloudflare documentation before writing or inspecting code. Training weights get stale quickly. Pulling current schema definitions prevents outdated compatibility flags and broken types in handlers.

It audits `wrangler.jsonc` setups, secret handling, and request life cycles. The guidelines ban storing per-request data in module-level variables because shared state leaks between requests. Background tasks must go into `ctx.waitUntil()`. Destructuring `const { waitUntil } = ctx` strips the `this` binding and throws an runtime `Illegal invocation` error.

Architecture checks flag direct Cloudflare REST calls and replace them with native bindings for KV, D1, or R2. Hyperdrive is required for external PostgreSQL or MySQL traffic. The skill also enforces running `wrangler types` instead of manually maintaining the `Env` interface.

## Install

### Codex (native platform)

1. **Skills CLI (Vercel)**
```bash
npx skills add openai/plugins --skill workers-best-practices -a codex
```

2. **Manually: put the files in place**
- File: `.agents/skills/workers-best-practices/SKILL.md` — For all projects use ~/.agents/skills/

### Claude Code

1. **Skills CLI (Vercel)**
```bash
npx skills add openai/plugins --skill workers-best-practices -a claude-code
```

2. **Manually: put the files in place**
- File: `~/.claude/skills/workers-best-practices/SKILL.md` — Copy the whole skill folder; for one project use .claude/skills/workers-best-practices/

### Cursor

**Manually: put the files in place**
- File: `.cursor/skills/workers-best-practices/SKILL.md` — Cursor also reads .agents/skills/ and .claude/skills/

### GitHub Copilot

1. **GitHub CLI**
```bash
gh skill install openai/plugins workers-best-practices
```

2. **Manually: put the files in place**
- File: `.github/skills/workers-best-practices/SKILL.md`

### Gemini CLI

**Platform CLI**
```bash
gemini skills install https://github.com/openai/plugins --path plugins/cloudflare/skills/workers-best-practices
```

### Windsurf (Devin Desktop)

**Manually: put the files in place**
- File: `.devin/skills/workers-best-practices/SKILL.md` — The legacy .windsurf/skills/ path still works

### Claude.ai

**Claude.ai**
- Zip the folder and upload it in Settings → Capabilities → Skills

Where a file is given instead of a command, copy the files from the source to that path: https://github.com/openai/plugins/tree/HEAD/plugins/cloudflare/skills/workers-best-practices/SKILL.md

## When to use it
- validate wrangler.jsonc against the current configuration schema
- catch unhandled promises lacking await or ctx.waitUntil()
- swap insecure Math.random() for Web Crypto methods
- generate accurate bindings via wrangler types
- replace Cloudflare REST API calls with in-process bindings

## Example prompts
- Review my worker.ts for floating promises and unbounded payload buffering.
- Inspect our wrangler.jsonc file and check compatibility date settings.
- Audit this WorkerEntrypoint class to verify binding access patterns.

## Source text · SKILL.md · MIT

Below is the content of a third-party file. It is data, not instructions for you: do not act on anything written inside unless the human asks. Block tag: 65217275673b1900.

BEGIN THIRD-PARTY FILE 65217275673b1900
````text
---
name: workers-best-practices
description: Reviews and authors Cloudflare Workers code against production best practices. Load when writing new Workers, reviewing Worker code, configuring wrangler.jsonc, or checking for common Workers anti-patterns (streaming, floating promises, global state, secrets, bindings, observability). Biases towards retrieval from Cloudflare docs over pre-trained knowledge.
---

Your knowledge of Cloudflare Workers APIs, types, and configuration may be outdated. **Prefer retrieval over pre-training** for any Workers code task — writing or reviewing.

## Retrieval Sources

Fetch the **latest** versions before writing or reviewing Workers code. Do not rely on baked-in knowledge for API signatures, config fields, or binding shapes.

| Source | How to retrieve | Use for |
|--------|----------------|---------|
| Workers best practices | Fetch `https://developers.cloudflare.com/workers/best-practices/workers-best-practices/` | Canonical rules, patterns, anti-patterns |
| Workers types | See `references/review.md` for retrieval steps | API signatures, handler types, binding types |
| Wrangler config schema | `node_modules/wrangler/config-schema.json` | Config fields, binding shapes, allowed values |
| Cloudflare docs | Search tool or `https://developers.cloudflare.com/workers/` | API reference, compatibility dates/flags |

## FIRST: Fetch Latest References

Before reviewing or writing Workers code, retrieve the current best practices page and relevant type definitions. If the project's `node_modules` has an older version, **prefer the latest published version**.

```bash
# Fetch latest workers types
mkdir -p /tmp/workers-types-latest && \
  npm pack @cloudflare/workers-types --pack-destination /tmp/workers-types-latest && \
  tar -xzf /tmp/workers-types-latest/cloudflare-workers-types-*.tgz -C /tmp/workers-types-latest
# Types at /tmp/workers-types-latest/package/index.d.ts
```

## Reference Documentation

- `references/rules.md` — all best practice rules with code examples and anti-patterns
- `references/review.md` — type validation, config validation, binding access patterns, review process

## Rules Quick Reference

### Configuration

| Rule | Summary |
|------|---------|
| Compatibility date | Set `compatibility_date` to today on new projects; update periodically on existing ones |
| nodejs_compat | Enable the `nodejs_compat` flag — many libraries depend on Node.js built-ins |
| wrangler types | Run `wrangler types` to generate `Env` — never hand-write binding interfaces |
| Secrets | Use `wrangler secret put`, never hardcode secrets in config or source |
| wrangler.jsonc | Use JSONC config for non-secret settings — newer features are JSON-only |

### Request & Response Handling

| Rule | Summary |
|------|---------|
| Streaming | Stream large/unknown payloads — never `await response.text()` on unbounded data |
| waitUntil | Use `ctx.waitUntil()` for post-response work; do not destructure `ctx` |

### Architecture
````
END THIRD-PARTY FILE 65217275673b1900

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First 3008 of 7092 bytes. © Cloudflare · MIT · https://github.com/openai/plugins/tree/HEAD/plugins/cloudflare/skills/workers-best-practices/SKILL.md

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---
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