Cloudflare VibeSDK is an open-source platform for building and deploying full-stack applications through an AI coding agent. Users describe an application, review the agent's questions and edits, inspect previews and errors, and iterate through deployment on Cloudflare. The catalogue entries provide skills and instructions for working with the platform.
Borrowing it
Nothing to install: this file belongs to cloudflare/vibesdk. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/cloudflare/vibesdk/main/CLAUDE.mdgit clone --depth 1 https://github.com/cloudflare/vibesdkWrote 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/instructions/cloudflare/vibesdk/claude-md)<a href="https://agentmods.dev/instructions/cloudflare/vibesdk/claude-md"><img src="https://agentmods.dev/badge/instructions/cloudflare/vibesdk/claude-md/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/instructions/cloudflare/vibesdk/claude-md"><img src="https://agentmods.dev/badge/instructions/cloudflare/vibesdk/claude-md.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 | $0.01448 | $0.01448 |
| Opus 5.5 | $0.00579 | $0.00579 |
| Sonnet 5.5 | $0.00290 | $0.00290 |
| Haiku 4.5 | $0.00145 | $0.00145 |
Grade A, and why
vibesdk CLAUDE.md 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 2mo 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.
How it starts
The opening of the file, as written. The whole thing — 160 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code when working with code in this repository.
Communication Style
- Be professional, concise, and direct
- Do NOT use emojis in code reviews, changelogs, or any generated content. You may use professional visual indicators or favor markdown formatting over emojis.
- Focus on substance over style
- Use clear technical language
Project Overview
VibeSDK is an agentic full-stack application builder on Cloudflare.
Tech Stack:
- Frontend: React 19, TypeScript, Vite, TailwindCSS, React Router v7
- Backend: Cloudflare Workers, Durable Objects, Hono, D1, R2, and KV
- Agent: Cloudflare Think with AI Gateway model routing
- Workspace: SpaceDO Durable Objects
- Version history: Cloudflare Artifacts
- Preview runtime: Worker Loader bindings and Dynamic Workers
- Generated app data: Durable Object Facets with isolated SQLite
- WebSocket: PartySocket for real-time communication
Project Structure:
/src- React frontend, API types, and API client/worker/agents/think- ThinkAgent, prompts, skills, workspace adapter, and tools/worker/agents/core/behaviors/think.ts- Think host orchestration/worker/api- Routes, controllers, handlers, and WebSocket types/worker/database- D1 schema and services/space- SpaceDO, Artifacts synchronization, preview bundling, and App Facets/sdk- TypeScript client SDK/migrations- D1 migrations/scripts- Setup and deployment utilities
Key Architectural Patterns
ThinkAgent:
- One Agent backed by a Durable Object per app session
- Owns conversation, context selection, skills, streaming, tools, and step limits
- Uses explicit SpaceDO-backed tools; workspace bash is disabled
Workspace and Versioning:
- SpaceDO owns the isolated live workspace and files
- Cloudflare Artifacts owns durable commits, branches, history, and restore points
commitsaves without deploying;deploy_spacecommits and rebuilds the preview- Rollback applies a selected tree, creates a new commit, and redeploys
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.
- 2mo ago First seen · 160 lines · 1,448 tokens per session scan A d5a9256a8c56
vibesdk CLAUDE.md is an instructions file published in the GitHub repository cloudflare/vibesdk (5,461 stars, last pushed 15d ago), licensed MIT. It adds 1,448 tokens to every session, about $0.0058 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
vibesdk CLAUDE.md compared with instructions from other repositories
| Mod | Type | Stars | Last push | Licence | Scan | Tokens | Works with |
|---|---|---|---|---|---|---|---|
| vibesdk CLAUDE.mdcloudflare/vibesdk | Instructions file | 5.5k | 15d ago | MIT | A | 1,448 | Claude Code |
| vibe-coding-prompt-template backend.instructions.mdKhazP/vibe-coding-prompt-template | Instructions file | 3.2k | 1mo ago | MIT | A | 139 | GitHub Copilot |
| vscode buildNext.instructions.mdmicrosoft/vscode | Instructions file | 195k | today | MIT | A | 9,719 | GitHub Copilot |
| next.js AGENTS.mdvercel/next.js | Instructions file | 143k | today | MIT | A | 7,461 | Codex, OpenCode |
| langchain AGENTS.mdlangchain-ai/langchain | Instructions file | 149k | today | MIT | A | 4,680 | Codex, OpenCode |
| vscode oss-third-party-notices.instructions.mdmicrosoft/vscode | Instructions file | 195k | today | MIT | A | 5,516 | GitHub Copilot |
| vscode copilot-instructions.mdmicrosoft/vscode | Instructions file | 195k | today | MIT | A | 3,093 | GitHub Copilot |