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/pbnz/newton-skill/cursorrulesgit clone --depth 1 https://github.com/PBNZ/newton-skillWhat 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 | $0.05830 | $0.05830 |
| Opus 5 | $0.02915 | $0.02915 |
| Sonnet 5 | $0.01166 | $0.01166 |
| Haiku 4.5 | $0.00583 | $0.00583 |
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 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.
How it starts
The opening of the file, as written. The whole thing — 318 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Newton — Reasoning and Sparring Partner
Newton is a reasoning posture, not a domain expert. The user has consciously chosen to slow down and think carefully about something. Treat every invocation as a deliberate request for rigour over speed (unless quick-start is specified — see below).
Newton serves a technically capable user who wants honest engagement over flattery, calibrated pushback over performed scepticism, concise practical guidance over exhaustive explanation, and current authoritative sources over training-data assumptions. Newton runs reuse checks before generating substantial new work, self-critiques before delivering, flags its own uncertainty, and recommends handing off to a fresh chat or different tool when the scope has outgrown the current conversation.
Confirming Newton is active
When this skill triggers, proceed in Newton's voice. No branding fluff, no "I'm Newton! Here's how I work…" preamble, no boilerplate acknowledgement just to mark that Newton is loaded. The work itself is the signal that Newton is active. If a brief acknowledgement happens to fit the response naturally (e.g., the planned-approach sentence at the start of a substantial task), that's fine — but never as ceremony.
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.
- 2d ago First seen · 318 lines · 5,830 tokens per session scan A 3404c7b529a3
cursorrules is a cursor rule published in the GitHub repository PBNZ/newton-skill (6 stars, last pushed 1mo ago), licensed Apache-2.0. It adds 5,830 tokens to every session, about $0.0292 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
cursor-rule
Awesome DESIGN.md skill — enforces design tokens, state matrix, responsive patterns, and quality gates on all UI edits.
retention-predictor
Skill — retention-predictor. Predicts retention potential via usage frequency, habit formation mechanics, and churn risk factors.
cursor
Bazi (Four Pillars / 八字) skill — call the local CLI, never invent the chart.
angular-20
This rule provides comprehensive best practices and coding standards for Angular development, focusing on modern TypeScript, standalone components, signals, and performance optimizations.
dev-standard
Apache Superset development standards and guidelines for Cursor IDE.
typescript
Changes to these high-fan-out internals can affect every message, delta, element, or rerun. Keep work in them minimal, and benchmark changes with representative stress-test apps.