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.
npx agentmods add rules/tw-haiven/haiven-mcp-server/frontend-rulesgit clone --depth 1 https://github.com/tw-haiven/haiven-mcp-serverWrote 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/rules/tw-haiven/haiven-mcp-server/frontend-rules)<a href="https://agentmods.dev/rules/tw-haiven/haiven-mcp-server/frontend-rules"><img src="https://agentmods.dev/badge/rules/tw-haiven/haiven-mcp-server/frontend-rules.svg" alt="Measured on agentmods" 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 | $0.00008 | $0.00109 |
| Opus 5 | $0.00004 | $0.00055 |
| Sonnet 5 | $0.00002 | $0.00022 |
| Haiku 4.5 | $0.00001 | $0.00011 |
Grade A, and why
frontend-rules 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 5d 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.
What it actually says
- 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 the "prettier" library for formatting
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.
- 5d ago First seen · 8 lines · 8 tokens per session scan A fa71ef9b1318
frontend-rules 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 8 tokens to every session and 109 once invoked, about $0.0000 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.
Other cursor rules, from other repositories
state-management
Use the following stack. Do not introduce or recommend Redux or React Context for shared/global state.
backend
Backend development rules for TT Studio - AI model management backend.
new-component
Workflow for creating new React components.
performance
Frontend performance optimization rules. Apply when optimizing UI or bundle.
middleware-auth
Next.js middleware auth — prevents auth logic being placed in middleware instead of route handlers.
frontend-architecture
Vite + React SPA architecture - directory layout, providers, bundle splitting. Tailwind styling in tailwind.mdc.