durable-objects

A guide for Cloudflare Durable Objects, which are named, stateful pieces of server code used to coordinate activity for a specific group or resource.

In plain words
What is it for?
It helps create chat rooms, multiplayer games, and booking systems, including RPC methods, SQLite storage, scheduled alarms, WebSockets, Workers integration, configuration, and tests.
Why use it?
It helps build reliable shared state and communication where many users or requests need to work with the same data at the same time.

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/jxck/dotfiles/durable-objects
Any agent
npx skills add Jxck/dotfiles --skill durable-objects
Clone the repo
git clone --depth 1 https://github.com/Jxck/dotfiles

Made for: Claude Code, Codex.

Per session 76 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,361 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. Scan, not verified.
Origin unknown 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 $0.00076 $0.01361
Opus 5 $0.00038 $0.00681
Sonnet 5 $0.00015 $0.00272
Haiku 4.5 $0.00008 $0.00136

Measured 2d ago against content hash cd6797cb18f3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 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.

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> {
.agents/skills/durable-objects/SKILL.md · 187 lines

The source is not reproduced here

No licence file

A repository with no LICENSE is all rights reserved by default, so the body is not copied here. The metadata, the measurements and the link are.

Read it on GitHub

Files

What ships with it

3 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. 2d ago First seen · 187 lines · 76 tokens per session scan A cd6797cb18f3

Subscribe to this mod's changes

durable-objects is a skill published in the GitHub repository Jxck/dotfiles (95 stars, last pushed 4d ago), with no licence file. It adds 76 tokens to every session and 1,361 once invoked, about $0.0004 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 2026-08-30.