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.
git clone --depth 1 https://github.com/Juliocbm/beacon-docsWrote 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/juliocbm/beacon-docs/beacon)<a href="https://agentmods.dev/rules/juliocbm/beacon-docs/beacon"><img src="https://agentmods.dev/badge/rules/juliocbm/beacon-docs/beacon/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.
<a href="https://agentmods.dev/rules/juliocbm/beacon-docs/beacon"><img src="https://agentmods.dev/badge/rules/juliocbm/beacon-docs/beacon.svg" alt="Reviewed on agentmods" width="80" 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 | $0.01058 | $0.01058 |
| Opus 5.5 | $0.00423 | $0.00423 |
| Sonnet 5.5 | $0.00212 | $0.00212 |
| Haiku 4.5 | $0.00106 | $0.00106 |
Grade A, and why
beacon 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.
Copies of this mod
1 near-identical copy found in the catalogue:
- cursorrules — 95% identical, 6 lines differ
How it starts
The opening of the file, as written. The whole thing — 52 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Universal rules
- One doc = one category. Never duplicate across folders.
- Status via folder, never filename. Closed plan →
_archive/, never*_DONE.mdor*_v2.md. - kebab-case for all filenames. No camelCase, no snake_case, no spaces.
- README required in every category folder.
- ADRs are append-only. Supersede with a new ADR; never edit an accepted one.
- Evaluations are immutable snapshots. To revise, create a new dated file.
- Plans archive to
_archive/when done. Move them, never rename. - Generated AI files (this one) must match
docs/_meta/convention.md. Runbeacon syncafter editing the convention. - 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 inevaluations/.
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/. Runbeacon 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>-retrospectiveand 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 inreference/. - 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/.
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.
- 1mo ago First seen · 52 lines · 1,058 tokens per session scan A 0872c9f30e27
beacon is a cursor rule published in the GitHub repository Juliocbm/beacon-docs (6 stars, last pushed 4mo ago), licensed MIT. It adds 1,058 tokens to every session, about $0.0042 per session on Opus 5.5. 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
ponytail
Ponytail, lazy senior dev mode. Always pick the simplest solution that works.
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.
prefer-assertions-over-defensive-checks
Prefer assertions over defensive checks when data is guaranteed to be valid.
prefer-direct-imports-over-module-mocks
Prefer extracting a testable core over vi.mock / vi.resetModules when unit tests need to reach production logic entangled with config, env, or singletons.
config-validation-and-normalization
Config validation and normalization responsibilities (defineConfig normalizes, the orm section schema validates and resolves paths, the loader reports per-section diagnostics).