cloudflare-durable-objects

cloudflare-durable-objects is a skill for Claude Code, Codex from secondsky/claude-skills. It costs 43 tokens per session (5,395 once invoked), scanned A, original, MIT.

A reference and coding guide for Cloudflare Durable Objects, which are stateful Workers components used to coordinate activity and store data. It covers real-time connections, SQLite storage, alarms, routing, and migrations.

In plain words
What is it for?
Use it when building chat rooms, multiplayer games, rate limiting, session management, leader election, or stateful workflows with Cloudflare Workers.
Why use it?
It gives developers one place to check the rules and common patterns needed to build and troubleshoot Durable Objects. This helps with issues such as class exports, migrations, and alarm failures.

Skill for Claude CodeCodex

Part of the cloudflare-durable-objects plugin — 1 skill, 5 commands, 3 agents shipped together

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/secondsky/claude-skills/cloudflare-durable-objects
Any agent
npx skills add secondsky/claude-skills --skill cloudflare-durable-objects
Clone the repo
git clone --depth 1 https://github.com/secondsky/claude-skills

Made for: Claude Code, Codex.

Or install cloudflare-durable-objects, the plugin that ships this one along with the rest of its 1 skill, 5 commands, 3 agents.

Wrote 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.

agentmods badge for cloudflare-durable-objects

README.md
[![agentmods](https://agentmods.dev/badge/skills/secondsky/claude-skills/cloudflare-durable-objects.svg)](https://agentmods.dev/skills/secondsky/claude-skills/cloudflare-durable-objects)
Your own site
<a href="https://agentmods.dev/skills/secondsky/claude-skills/cloudflare-durable-objects"><img src="https://agentmods.dev/badge/skills/secondsky/claude-skills/cloudflare-durable-objects.svg" alt="Measured on agentmods" height="20"></a>
Per session 43 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,395 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00043 $0.05395
Opus 5 $0.00022 $0.02697
Sonnet 5 $0.00009 $0.01079
Haiku 4.5 $0.00004 $0.00539

Measured yesterday against content hash 8f1c9245551c, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cloudflare-durable-objects scanned grade A with 1 finding 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 yesterday.

The scan reads SKILL.md. This mod also ships 14 executable files (scripts/check-versions.sh, scripts/migration-generator.sh, scripts/setup-vitest-do.sh, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

async fetch(request: Request, env: Env): Promise<Response> {
plugins/cloudflare-durable-objects/skills/cloudflare-durable-objects/SKILL.md · 581 lines

How it starts

The opening of the file, as written. The whole thing — 581 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cloudflare Durable Objects

Status: Production Ready ✅ Last Updated: 2025-11-25 Dependencies: cloudflare-worker-base (recommended) Latest Versions: [email protected]+, @cloudflare/[email protected]+ Official Docs: https://developers.cloudflare.com/durable-objects/

Table of Contents

What are Durable Objects?Quick StartWhen to Load ReferencesClass StructureState APIWebSocket HibernationAlarmsRPC vs HTTPStubs & RoutingMigrationsCommon PatternsCritical RulesKnown Issues

What are Durable Objects?

Globally unique, stateful objects with single-point coordination, strong consistency (ACID), WebSocket Hibernation (thousands of connections), SQLite storage (1GB), and alarms API.

Use for: Chat rooms, multiplayer games, rate limiting, session management, leader election, stateful workflows

Quick Start (10 Minutes)

Option 1: Scaffold New DO Project

npm create cloudflare@latest my-durable-app -- \
  --template=cloudflare/durable-objects-template --ts --git --deploy false
cd my-durable-app && bun install && npm run dev

Option 2: Add to Existing Worker

1. Install types:

bun add -d @cloudflare/workers-types

2. Create DO class (src/counter.ts):

import { DurableObject } from 'cloudflare:workers';

export class Counter extends DurableObject {
  async increment(): Promise<number> {
    let value: number = (await this.ctx.storage.get('value')) || 0;
    await this.ctx.storage.put('value', ++value);
    return value;
  }
}

export default Counter;  // CRITICAL

Read the full file on GitHub · 581 lines

Files

What ships with it

38 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.

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. yesterday First seen · 581 lines · 43 tokens per session scan A 8f1c9245551c

Subscribe to this mod's changes

cloudflare-durable-objects is a skill published in the GitHub repository secondsky/claude-skills (214 stars, last pushed yesterday), licensed MIT. It adds 43 tokens to every session and 5,395 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.