Cloudflare Durable Objects Builder
Build and review stateful coordination applications on Cloudflare.
The material is development guidance and shows no malware, credential theft, or covert exfiltration. However, it lacks least-privilege guidance, user confirmation, data-flow disclosure, sensitive-data boundaries, deployment rollback, and external-effect controls; examples include open CORS and production deployment commands, so points are deducted.
The structure is internally coherent and covers Durable Objects, SQLite, RPC, alarms, WebSockets, testing, and error handling, with basic failure guidance. It is nevertheless static documentation without committed key-path tests; examples and dependency versions may change with Cloudflare APIs, and abnormal-input and diagnostic coverage is limited. The static ceiling therefore applies.
The audience, scenarios, and several non-fit cases are reasonably clear, with Workers, Wrangler, and Vitest environment guidance. Precise trigger exclusions, input/output contracts, and Chinese-language support are absent, and core retrieval depends on Cloudflare-hosted overseas documentation without evidence of mainland-China reachability, so points are deducted.
The skill uses a readable main document plus reference files and includes configuration, testing, limitations, examples, and an Apache-2.0 license. It lacks skill-specific versioning, changelog, named maintenance responsibility, update path, FAQ, and complete installation guidance; publisher identity is also unverified, so points are deducted.
It can directly guide common Durable Objects work through configuration, code patterns, tests, and anti-patterns, and its core value proposition is clear. However, no real output or execution is statically verified, while retrieval, version compatibility, and example correctness still require user review; the static ceiling limits this to 6.
The skill cites Cloudflare documentation, API, best-practice, and example sources, and the repository has limited Semgrep CI evidence. It lacks committed tests covering the skill's key paths and third-party execution evidence, so independent reproduction is thin and the score remains limited.
- Before execution, verify the current Durable Objects API, compatibility date, Wrangler configuration, and Vitest dependency versions.
- Do not adopt the open CORS or production deployment examples directly; confirm authorization, environment, data scope, and rollback plans first.
- Core retrieval depends on Cloudflare-hosted overseas sites; confirm mainland-China reachability and prepare offline or mirrored references.
What does this skill do, and when should you use it?
This is the Durable Objects skill in the cloudflare/skills repository, intended for building stateful applications at the Cloudflare edge with Workers. It covers Durable Object classes, RPC methods, SQLite storage, alarms, WebSockets, Wrangler configuration, and Vitest testing. The skill favors retrieving current Cloudflare documentation because APIs and configuration may change. It is a good fit for strong consistency, per-entity persistence, and persistent-connection workloads, but not for stateless request handling or highly distributed independent fan-out requests.
It guides agents through creating and reviewing Durable Object classes, modeling coordination around rooms, games, or users, configuring Wrangler bindings and migrations, and writing code for RPC, SQLite, KV, alarms, and WebSockets. It recommends retrieving the relevant Durable Objects documentation, API reference, best-practices, and examples pages during implementation. It also supplies TypeScript examples for stub creation, storage operations, alarms, and tests using @cloudflare/vitest-pool-workers.
- A developer is designing a Durable Object for a chat room, multiplayer game, or collaborative document.
- A Workers application needs RPC methods, WebSockets, or per-entity scheduled work.
- A team must configure Durable Object bindings, SQLite migrations, and Wrangler project settings.
- A developer is reviewing concurrency, persistence, sharding, or parent-child relationships in existing Durable Objects code.
- A developer is writing unit or integration tests for Durable Objects with @cloudflare/vitest-pool-workers.
What are this skill's strengths and limitations?
- Covers the Durable Objects workflow from Workers integration and Wrangler configuration through storage, RPC, alarms, and testing.
- Includes directly applicable TypeScript configuration, implementation, and test examples.
- States concrete rules and anti-patterns for coordination scope, persistence, and concurrency control.
- Its retrieval-first approach is useful for Cloudflare tasks where APIs and configuration can change.
- Its scope is limited to Durable Objects rather than the sibling skills in the repository.
- It relies on access to Cloudflare documentation for current API and configuration details.
- The source provides no standalone automated test results or version compatibility matrix.
- The examples assume a Cloudflare Workers, Durable Objects, and Vitest development setup without providing a complete project scaffold.
How do you install this skill?
The repository follows the Agent Skills standard. Install the full collection with npx skills add https://github.com/cloudflare/skills; for OpenAI Codex, copy the skill folder into ~/.codex/skills/. You can also clone the repository and copy skills/durable-objects into the appropriate agent skill directory. The source does not document a dedicated command for installing only this skill.
How do you use this skill?
Ask the agent for a Durable Objects task, for example: “Create a Cloudflare Durable Object chat room using SQLite and RPC, and write Vitest tests for it.” The skill is contextually loaded when its triggers match; during implementation, retrieve the relevant Cloudflare documentation page.
How does this skill compare with similar options?
Compared with plain, stateless Cloudflare Workers, this skill targets workloads requiring coordination, strong consistency, per-entity storage, persistent connections, or scheduled work per entity. The source recommends plain Workers for stateless request handling.