supabase

supabase is a cursor rule for Cursor from kensaurus/cursor-kenji. It costs 0 tokens per session (310 once invoked), scanned A, original, MIT.

Supabase project rules cover database queries, row-level security, migrations, edge functions, authentication, and data fetching. Supabase is a hosted database and backend service.

In plain words
What is it for?
Use them when building tables, policies, migrations, authenticated functions, or real-time and client-side data access.
Why use it?
They reduce inconsistent database code and help prevent missing access controls, unsafe inputs, and incomplete migrations.

Cursor rule for Cursor

Written for Cursor: a Cursor rule (.mdc).

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/kensaurus/cursor-kenji/supabase
Clone the repo
git clone --depth 1 https://github.com/kensaurus/cursor-kenji

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 supabase

README.md
[![agentmods](https://agentmods.dev/badge/rules/kensaurus/cursor-kenji/supabase.svg)](https://agentmods.dev/rules/kensaurus/cursor-kenji/supabase)
Your own site
<a href="https://agentmods.dev/rules/kensaurus/cursor-kenji/supabase"><img src="https://agentmods.dev/badge/rules/kensaurus/cursor-kenji/supabase.svg" alt="Measured on agentmods" height="20"></a>
Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 310 The whole file, excluding the scripts and references it only reads on demand.
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 5.1 $0.00000 $0.00310
Opus 5 $0.00000 $0.00155
Sonnet 5 $0.00000 $0.00062
Haiku 4.5 $0.00000 $0.00031

Measured 2d ago against content hash 140240a0dfc5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

supabase 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.

rules/project-starter/supabase.mdc · 38 lines

What it actually says

Supabase Conventions

Client Usage

  • Use typed Supabase client from @/lib/supabase
  • Always use .select() with specific columns (never SELECT *)
  • Use .single() when expecting one row
  • Handle errors: const { data, error } = await supabase.from(...)

RLS

  • Every table MUST have RLS enabled
  • Test policies after creation with Supabase MCP
  • Use auth.uid() for user-scoped access
  • Use EXISTS subqueries for role-based access (avoid function calls in policies)

Migrations

  • File naming: YYYYMMDD_description.sql
  • Always include created_at TIMESTAMPTZ DEFAULT now()
  • Always include updated_at with moddatetime trigger
  • Always add indexes on foreign keys
  • After migration: regenerate types with supabase gen types typescript

Edge Functions

  • Verify JWT or API key in every function
  • Handle CORS preflight OPTIONS requests
  • Return proper status codes (401, 403, 400, 500)
  • Use Deno.env.get() for secrets

Data Fetching

  • Server Components: use Supabase server client directly
  • Client Components: use TanStack Query with Supabase client
  • Real-time: subscribe at component level, cleanup on unmount
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 · 38 lines · 0 tokens per session scan A 140240a0dfc5

Subscribe to this mod's changes

supabase is a cursor rule published in the GitHub repository kensaurus/cursor-kenji (9 stars, last pushed 8d ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 310 tokens. 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 2026-09-03.