cursor-cloud

Setup and run instructions for T3 Code in Cursor Cloud, a hosted computer environment made for Cursor coding agents. They cover the preinstalled Node.js, package manager, and development commands.

In plain words
What is it for?
Installing dependencies, checking and formatting code, starting the web app, running its server or web client separately, and handling Cursor Cloud's shell and port setup.
Why use it?
They explain environment-specific details such as which Node.js version commands use and how the web, server, and contracts processes connect.

Cursor rule for Cursor

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 rules/pingdotgg/t3code/cursor-cloud
Clone the repo
git clone --depth 1 https://github.com/pingdotgg/t3code

Made for: Cursor.

Per session 1,327 This file is loaded in full into every session.
When invoked 1,327 The same file — it is already loaded in full.
Security scan A 0 findings. 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 $0.01327 $0.01327
Opus 5 $0.00664 $0.00664
Sonnet 5 $0.00265 $0.00265
Haiku 4.5 $0.00133 $0.00133

Measured 2d ago against content hash 9f8540c10651, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cursor-cloud 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 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.

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.

.cursor/rules/cursor-cloud.mdc · 73 lines

How it starts

The opening of the file, as written. The whole thing — 73 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cursor Cloud specific instructions

These notes apply only to Cursor Cloud agents (kept out of the shared AGENTS.md since T3 Code is developed in many places). They cover the pre-provisioned VM environment and non-obvious run caveats.

Toolchain

Pre-installed and wired into login shells (~/.bashrc/~/.profile): Node 24 (via nvm), the global vp (Vite+) CLI, and its bundled pnpm. vp is the package manager + task runner for this repo (vp i, vp check, vp run typecheck, vp test, vp run --filter <pkg> <script>).

  • Node gotcha: the base image also ships an older Node on /exec-daemon that wins on PATH in non-login shells. Run commands in a login shell (bash -lc '...') or prepend $HOME/.nvm/versions/node/v24.13.1/bin so Node 24 (engines.node: ^24.13.1) is used.
  • vp check also runs the formatter (not just lint); markdown edits must be formatter-clean. Run vp check --fix before committing.

Running the web app

  • npm run dev (from repo root) starts contracts (watch), web (Vite, port 5733), and the server (node --watch, port 13773) together, auto-wiring VITE_HTTP_URL/VITE_WS_URL. Use npm run dev:server / npm run dev:web for one side. If base ports are taken it auto-offsets to the next free pair, so read the actual ports from stdout. Avoid production build/start in dev.
  • Auth/pairing: the server is unauthenticated by default and prints a pairing URL to stdout on startup (e.g. http://localhost:5733/pair#token=XXXX). Open that URL in the browser to pair before the web UI can talk to the server. Server state (SQLite, auth, projects) lives under ~/.t3 (T3CODE_HOME); multiple npm run dev instances bind different ports but share that same DB.
  • Agent providers are external CLIs (codex, claude, cursor-agent, opencode) probed on PATH. Without one installed the UI loads but no agent can run. Claude Code (npm i -g @anthropic-ai/claude-code) works headlessly using ANTHROPIC_API_KEY from the environment (the server forwards process.env to the child; no interactive claude auth login needed). Provider probing runs at startup and refreshes roughly every 5 minutes — restart the dev server to pick up a newly installed provider CLI immediately.

Read the full file on GitHub · 73 lines

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 · 73 lines · 1,327 tokens per session scan A 9f8540c10651

Subscribe to this mod's changes

cursor-cloud is a cursor rule published in the GitHub repository pingdotgg/t3code (21,041 stars, last pushed 2d ago), licensed MIT. It adds 1,327 tokens to every session, about $0.0066 per session on Opus 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.