general

General development rules for a project using Cursor and a Nix-based development environment. They cover navigation, architecture decisions, error handling, testing, file deletion, and code organization.

In plain words
What is it for?
Use them to find project guidance, run tools through Nix, consult architecture decisions, handle errors explicitly, write focused unit tests, and remove files safely.
Why use it?
They give coding agents consistent project conventions and reduce mistakes such as bypassing the expected environment, hiding failures, or duplicating concepts.

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/nerds-odd-e/doughnut/general
Clone the repo
git clone --depth 1 https://github.com/nerds-odd-e/doughnut

Made for: Cursor.

Per session 419 This file is loaded in full into every session.
When invoked 419 The same file — it is already loaded in full.
Security scan C 1 finding. 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 $0.00419 $0.00419
Opus 5 $0.00210 $0.00210
Sonnet 5 $0.00084 $0.00084
Haiku 4.5 $0.00042 $0.00042

Measured 2d ago against content hash 041dea63cb03, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade C, and why

general scanned grade C with 1 finding 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.

Recursive force deletehighDestructive command

rm -rf with a variable or a broad path is one typo away from removing the wrong tree.

- When deleting files, prefer `trash` from the Nix environment instead of `rm -f` or `rm -rf`.
.cursor/rules/general.mdc · 21 lines

What it actually says

General Development Rules

  • Start with .cursor/agent-map.md for navigation, focused commands, service assumptions, generated API guidance, ADRs, and log inspection.
  • Architectural decisions: humans approve via docs/adrs/; agents use adr-awareness (see architecture-decisions.mdc).
  • Run repo tooling through Nix (CURSOR_DEV=true nix develop -c …) unless documented otherwise (e.g. Cloud VM). Git commands do not need the Nix prefix — run git directly.
  • For Cursor Cloud VM without Nix, use the cloud-vm-setup skill.
  • When deleting files, prefer trash from the Nix environment instead of rm -f or rm -rf.
  • Keep high cohesion: minimize duplication, keep one representation for each concept, and place related code together.
  • Keep changes simple. Do not add defensive layers unless observed behavior requires them.
  • Never silently swallow failures — always-applied error-handling.mdc.
  • Unit tests use the "small test" style (stable boundary, data over mocks, focused assertions, concise makeMe) — always-applied unit-testing.mdc.
  • Name permanent artifacts by product capability, not development history (never GSD phase numbers).
  • Do not add comments or docs about past implementations in product code, tests, or permanent docs; code readers care about the current state.
  • .planning/ exception: while a plan is in progress, keep enough history in the PLAN file (slice status, brief learnings) to stop and resume across sessions. When the plan is fully executed into code and permanent docs, actively clean up spent planning history (see planning.mdc).
  • Planning layout and GSD coexistence: .cursor/rules/planning.mdc, .cursor/rules/gsd-coexistence.mdc.
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 · 21 lines · 419 tokens per session scan C 041dea63cb03

Subscribe to this mod's changes

general is a cursor rule published in the GitHub repository nerds-odd-e/doughnut (49 stars, last pushed 2d ago), licensed MIT. It adds 419 tokens to every session, about $0.0021 per session on Opus 5. A static security scan graded it C with 1 finding (recursive force delete). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.