frp

A code-reuse rulebook for a repository. It requires checking a function registry before writing a new function, so existing code can be reused or extended.

In plain words
What is it for?
Use it when adding functions to a codebase that maintains a FUNCTIONS.md registry and wants a lookup-before-create workflow.
Why use it?
It reduces duplicate code and helps keep related logic in one place. It also records whether a function was reused, extended, or newly created.

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/bullboy1/babycoding/frp
Clone the repo
git clone --depth 1 https://github.com/bullboy1/babycoding

Made for: Cursor.

Per session 2,560 This file is loaded in full into every session.
When invoked 2,560 The same file — it is already loaded in full.
Security scan A 0 findings. 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 $0.02560 $0.02560
Opus 5 $0.01280 $0.01280
Sonnet 5 $0.00512 $0.00512
Haiku 4.5 $0.00256 $0.00256

Measured yesterday against content hash 653516b7734d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

frp 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 yesterday.

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.

.cursor/rules/frp.mdc · 111 lines

How it starts

The opening of the file, as written. The whole thing — 111 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Cursor Rules — Function Registry Protocol (FRP) v1.4

Mandatory for every task in this repo. Goals: zero duplicate code, minimal token spend, clean layered architecture.

0. Session start

  1. Read FUNCTIONS.md. If Stage 3 (sharded): read root index + only the shards of modules this task touches.
  2. No FUNCTIONS.md → run §6 Bootstrap before anything else.
  3. Function count crossed a §7 threshold → perform that stage upgrade within this task.
  4. Canvas on → read docs/registry/inbox.md if present; pending entries are user requests sent from the canvas: do them first, mark each [done YYYY-MM-DD] when finished.

1. Lookup — before writing ANY function

  1. Search FUNCTIONS.md (name + desc columns) by capability keywords.
  2. HIT → grep the code to confirm existence and signature → REUSE. Reimplementing a registered capability is a protocol violation.
  3. NEAR-HIT (covers ≥80% of the need) → EXTEND the existing function (add a param/option). Do not create a sibling.
  4. MISS → create, following §2–§4.
  5. Mandatory trace — print one line per decision in your reply, before writing code:
    • REGISTRY: HIT parseDate (L1) src/utils/time.py
    • REGISTRY: EXTEND fetchOrder (L3) src/orders/api.py — add includeDrafts flag
    • REGISTRY: MISS -> new renderBadge (L2) src/ui/badge.tsx

2. Creation rules

  • Names: verb+noun, repo's dominant casing (parseInvoice / parse_invoice). Searchable; no abbreviations except: id, url, db, cfg, ctx.
  • One function, one responsibility. Function ≤ 50 lines. File ≤ 300 lines. Nesting ≤ 3 levels.
  • Rule of Three: a 2nd duplication is tolerated; the 3rd MUST be extracted into a shared L1/L2 component and registered.
  • Folders: depth ≤ 4 from repo root, lowercase, named by domain/feature — never by person, date, or version.
  • Imports flow downward only: L4 → L3 → L2 → L1. L1 imports no project code. An upward import is a bug.
  • Shared constants/types obey the same lookup-before-create rule (grep first).
  • Comments explain WHY, never WHAT. One-line docstring required on L1/L2; on L3/L4 only when non-obvious.
  • Minimal diff: touch nothing outside task scope. No drive-by refactors.

Read the full file on GitHub · 111 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. yesterday First seen · 111 lines · 2,560 tokens per session scan A 653516b7734d

Subscribe to this mod's changes

frp is a cursor rule published in the GitHub repository bullboy1/babycoding (4 stars, last pushed 1mo ago), licensed MIT. It adds 2,560 tokens to every session, about $0.0128 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.