cursorrules

cursorrules is a cursor rule for Cursor from tw-haiven/haiven-mcp-server. It costs 395 tokens per session, scanned A, original, Apache-2.0.

A set of coding rules that requires test-driven development, or TDD: write a failing test first, then add the code that makes it pass.

In plain words
What is it for?
Use it when building features in the described Python backend or JavaScript, React, and Next.js frontend, especially when following the stated test and startup steps.
Why use it?
It provides a repeatable workflow for making changes, while also recording project-specific testing, dependency, and folder conventions.

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/tw-haiven/haiven-mcp-server/cursorrules
Clone the repo
git clone --depth 1 https://github.com/tw-haiven/haiven-mcp-server

Made for: Cursor.

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 cursorrules

README.md
[![agentmods](https://agentmods.dev/badge/rules/tw-haiven/haiven-mcp-server/cursorrules.svg)](https://agentmods.dev/rules/tw-haiven/haiven-mcp-server/cursorrules)
Your own site
<a href="https://agentmods.dev/rules/tw-haiven/haiven-mcp-server/cursorrules"><img src="https://agentmods.dev/badge/rules/tw-haiven/haiven-mcp-server/cursorrules.svg" alt="Measured on agentmods" height="20"></a>
Per session 395 This file is loaded in full into every session.
When invoked 395 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 $0.00395 $0.00395
Opus 5 $0.00198 $0.00198
Sonnet 5 $0.00079 $0.00079
Haiku 4.5 $0.00040 $0.00040

Measured 3d ago against content hash 76b95dfd52bf, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

cursorrules 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 3d 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.

.cursorrules · 30 lines

What it actually says

Tests

When I am not just asking a question, but we're building a new feature, then I would like you to always use TDD:

  1. write a test first
  2. run (or let me run) the test first so it can go red (fail) and ONLY then
  3. write the implementation
  4. run the test again to see if it passes

Ask me before making decisions like choosing a technology or framework

Help me always get to the next "runnable" step that I can commit, remind me to make commits when we get to a point that is a working state

Backend

  • Our backend is in Python and in the app/ subfolder. The app needs to be started from that directory.
  • The backend tests are in app/tests/
  • When running tests or the application, the virtual environment in app/.venv first needs to be activated
  • We're using constructor dependency injections to make our code more testable. Pass dependencies in via constructors, do not initialise them inside of a class.
  • When we wrap up a backend change, make sure to remind me to start up the whole application, to make sure that it's all well-integrated.

Frontend

  • Our frontend is in JavaScript, React, Next, in the ui/ subfolder, code in ui/src/, tests in ui/src/tests. Make sure to navigate into the ui/ subfolder before executing yarn tasks.
  • We're using Next in "client only" mode, NO server-side features, because we're distributing the frontend code as static resources that call a Python API for data
  • We're using vitest for testing
  • We're using the "prettier" library for formatting
  • Always use remix icons for icons
  • We are using yarn
  • Do not create JSDocs
  • Our components currently go in the ui/app folder, and the file naming convention is _name_of_component.js
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. 3d ago First seen · 30 lines · 395 tokens per session scan A 76b95dfd52bf

Subscribe to this mod's changes

cursorrules is a cursor rule published in the GitHub repository tw-haiven/haiven-mcp-server (0 stars, last pushed 9mo ago), licensed Apache-2.0. It adds 395 tokens to every session, about $0.0020 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 2026-08-31.