beacon-docs: Cursor rule for Cursor

.cursorrules

cursorrules is a cursor rule for Cursor from Juliocbm/beacon-docs. It costs 1,029 tokens per session, scanned A, a copy of beacon, MIT.

A set of project rules for storing decisions, plans, deferred work, and evaluations in documents. An ADR is a record of an important technical decision, while a monorepo is one repository containing multiple related projects or packages.

In plain words
What is it for?
Use it to decide where to record architecture decisions, multi-step work, postponed tasks, and retrospectives. It also defines rules for archiving plans, keeping accepted decisions unchanged, and maintaining documentation conventions.
Why use it?
It prevents important decisions and follow-up work from being lost in chat, and keeps project documents organized with consistent names, locations, and status rules.

Cursor rule for Cursor

Written for Cursor: installed under .cursor/.

This is Juliocbm/beacon-docs's own configuration. It tells Cursor how to work on beacon-docs itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything beacon-docs configures →

Reuse

Borrowing it

Nothing to install: this file belongs to Juliocbm/beacon-docs. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/Juliocbm/beacon-docs/main/.cursorrules
Clone the repo
git clone --depth 1 https://github.com/Juliocbm/beacon-docs

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/juliocbm/beacon-docs/cursorrules/github.svg)](https://agentmods.dev/rules/juliocbm/beacon-docs/cursorrules)
Your own site
<a href="https://agentmods.dev/rules/juliocbm/beacon-docs/cursorrules"><img src="https://agentmods.dev/badge/rules/juliocbm/beacon-docs/cursorrules/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for cursorrules

Your own site · 80×15
<a href="https://agentmods.dev/rules/juliocbm/beacon-docs/cursorrules"><img src="https://agentmods.dev/badge/rules/juliocbm/beacon-docs/cursorrules.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 1,029 This file is loaded in full into every session.
When invoked 1,029 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin 95% copy Near-identical to another mod 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 5.1 $0.01029 $0.01029
Opus 5.5 $0.00412 $0.00412
Sonnet 5.5 $0.00206 $0.00206
Haiku 4.5 $0.00103 $0.00103

Measured 1mo ago against content hash 4faf1f30b9a4, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, 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 1mo 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.

Origin

This is a copy

95% identical to beacon — 6 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.cursorrules · 46 lines

How it starts

The opening of the file, as written. The whole thing — 46 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Universal rules

  1. One doc = one category. Never duplicate across folders.
  2. Status via folder, never filename. Closed plan → _archive/, never *_DONE.md or *_v2.md.
  3. kebab-case for all filenames. No camelCase, no snake_case, no spaces.
  4. README required in every category folder.
  5. ADRs are append-only. Supersede with a new ADR; never edit an accepted one.
  6. Evaluations are immutable snapshots. To revise, create a new dated file.
  7. Plans archive to _archive/ when done. Move them, never rename.
  8. Generated AI files (this one) must match docs/_meta/convention.md. Run beacon sync after editing the convention.
  9. Don't create folders outside the convention. Run beacon enable <addon> or propose an ADR.

Persistence rule: Decisions live in ADRs, multi-step work lives in plans, deferred work lives in backlog, retrospection lives in evals. Chat memory is session-scoped and lost when the conversation ends. If you find yourself relying on chat memory to track a decision, plan, or follow-up — write the document instead.

Project-specific rules

  • operations/*.guide.md — deploy guides, admin runbooks, troubleshooting. Post-mortems go in evaluations/.

Workflow triggers — when to create documents

These are the conversational signals that should prompt you to create or update Beacon documents. Treat them as imperatives, not suggestions.

  • Design decision made → write an ADR before implementing. Decisions about architecture, dependencies, naming conventions, or future flexibility belong in adr/. Run beacon new adr <slug>. Draft the ADR inline; don't ask permission to write it.
  • Multi-step work agreed (3+ distinct actions) → write a plan with checkbox steps. Run beacon new plan <slug> and write bite-sized steps. Check off each step in the same commit that completes it. Don't keep multi-step work only in chat memory.
  • Scope deferred → capture it as a backlog item immediately. When the user says "let's do that later", "out of scope for now", "maybe v0.5", or similar, run beacon new todo <slug> and write the why plus acceptance criteria. Don't let deferred work live only in conversation.
  • Release shipped or milestone reached → write a dated retrospective eval. Run beacon new eval <slug>-retrospective and capture what worked, what didn't, what you'd do differently. Even a 10-line eval is better than zero.
  • Approach explained twice → write a pattern doc. If you find yourself explaining the same technical approach across multiple files or sessions, run beacon new pattern <slug> and capture it in reference/.
  • System structure changed → update or add an architecture doc. New module, new layer, new external dependency that affects how the system is shaped — that goes in architecture/.

Read the full file on GitHub · 46 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. 1mo ago First seen · 46 lines · 1,029 tokens per session scan A 4faf1f30b9a4

Subscribe to this mod's changes

cursorrules is a cursor rule published in the GitHub repository Juliocbm/beacon-docs (6 stars, last pushed 4mo ago), licensed MIT. It adds 1,029 tokens to every session, about $0.0041 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 95% identical to beacon, differing in 6 lines, and is treated as a copy.