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 d-padmanabhan/agent-engineering-handbook --skill workers-best-practicesgit clone --depth 1 https://github.com/d-padmanabhan/agent-engineering-handbookWrote 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/d-padmanabhan/agent-engineering-handbook/workers-best-practices)<a href="https://agentmods.dev/skills/d-padmanabhan/agent-engineering-handbook/workers-best-practices"><img src="https://agentmods.dev/badge/skills/d-padmanabhan/agent-engineering-handbook/workers-best-practices/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/d-padmanabhan/agent-engineering-handbook/workers-best-practices"><img src="https://agentmods.dev/badge/skills/d-padmanabhan/agent-engineering-handbook/workers-best-practices.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 | $0.00072 | $0.01585 |
| Opus 5 | $0.00036 | $0.00792 |
| Sonnet 5 | $0.00014 | $0.00317 |
| Haiku 4.5 | $0.00007 | $0.00159 |
Grade A, and why
workers-best-practices 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 9d 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.
This is a copy
100% identical to workers-best-practices — 135 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 128 lines — stays where its author put it; the contents beside it link to each section on GitHub.
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.
# 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-patternsreferences/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 |
What ships with it
2 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.
- 9d ago First seen · 128 lines · 72 tokens per session scan A f0e7f22cd5a1
workers-best-practices is a skill published in the GitHub repository d-padmanabhan/agent-engineering-handbook (17 stars, last pushed today), licensed MIT. It adds 72 tokens to every session and 1,585 once invoked, about $0.0004 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to workers-best-practices, differing in 135 lines, and is treated as a copy.
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