supabase-database

A set of practices for managing a Supabase database, including schema migrations, row-level security, authentication connections, and generated TypeScript types. Supabase is a hosted database and application-backend service.

In plain words
What is it for?
Use it to create tables and migrations, restrict rows with database policies, connect Supabase authentication, and generate types for application code.
Why use it?
It helps prevent accidental data exposure and migration problems by checking access rules for anonymous, user, and administrator accounts.

Skill for Claude CodeCodex

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 skills/monkilabs/opencastle/supabase
Any agent
npx skills add monkilabs/opencastle --skill supabase
Clone the repo
git clone --depth 1 https://github.com/monkilabs/opencastle

Made for: Claude Code, Codex.

Per session 49 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 521 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 $0.00049 $0.00521
Opus 5 $0.00024 $0.00260
Sonnet 5 $0.00010 $0.00104
Haiku 4.5 $0.00005 $0.00052

Measured 2d ago against content hash c700ebd0e72d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

supabase-database 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.

The scan reads SKILL.md. This mod also ships 1 executable file (config.ts), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

src/orchestrator/plugins/supabase/SKILL.md · 41 lines

What it actually says

Supabase Database

Project schema, roles, migration history, auth flow, and key files: supabase-config.md. Docs: https://supabase.com/docs

RLS gotchas

  • ENABLE ROW LEVEL SECURITY with no policy denies everything. Enabling and adding policies must land in the same migration.
  • Policies are per-operation. FOR SELECT USING (...) does not cover writes; INSERT needs WITH CHECK, not USING.
  • auth.uid() is the owner check (auth.uid() = id). It is NULL for the anon role, so any policy relying on it silently blocks anonymous access.
  • Test every policy against all three roles — anon, user, admin. A policy that works as your own user tells you nothing about anon.
  • Reference auth.users(id) with ON DELETE CASCADE on profile-style tables, or deleted users leave orphans.

Confirm RLS coverage before shipping:

SELECT tablename, rowsecurity FROM pg_tables WHERE schemaname = 'public';

Migration workflow

  1. Name migrations YYYYMMDD_add_profiles.sql; comment intent and rollback considerations inline.
  2. Apply to a local/ephemeral DB; run smoke tests plus per-role RLS checks.
  3. Review the SQL for destructive actions (table drops, column rewrites) — those need a backfill script and phased rollout, never a single migration.
  4. Re-run in CI against a test replica with the full suite.
  5. Deploy via the safe-deploy pipeline, then re-verify RLS, indexes, and a data sanity query.

Regenerate types after every schema change (CI step):

supabase gen types typescript --project-id <project-id> > src/types/supabase.ts

Assert at steps 2 and 4 that the migration completes, per-role RLS queries still pass, and tests on changed paths pass. On failure: revert, adjust, re-run.

Files

What ships with it

1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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 · 41 lines · 49 tokens per session scan A c700ebd0e72d

Subscribe to this mod's changes

supabase-database is a skill published in the GitHub repository monkilabs/opencastle (61 stars, last pushed 5d ago), licensed MIT. It adds 49 tokens to every session and 521 once invoked, about $0.0002 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 2026-08-30.

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