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/fumito-ito/mdcvalultWrote 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/fumito-ito/mdcvalult/guidelines-for-writing-postgres-migrations-with-supabase-cli)<a href="https://agentmods.dev/rules/fumito-ito/mdcvalult/guidelines-for-writing-postgres-migrations-with-supabase-cli"><img src="https://agentmods.dev/badge/rules/fumito-ito/mdcvalult/guidelines-for-writing-postgres-migrations-with-supabase-cli/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/fumito-ito/mdcvalult/guidelines-for-writing-postgres-migrations-with-supabase-cli"><img src="https://agentmods.dev/badge/rules/fumito-ito/mdcvalult/guidelines-for-writing-postgres-migrations-with-supabase-cli.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 | $0.00000 | $0.00552 |
| Opus 5 | $0.00000 | $0.00276 |
| Sonnet 5 | $0.00000 | $0.00110 |
| Haiku 4.5 | $0.00000 | $0.00055 |
Grade A, and why
guidelines-for-writing-postgres-migrations-with-supabase-cli 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 9d 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
2 near-identical copies found in the catalogue:
- supabase-create-migration — 94% identical, 5 lines differ
- supabase-create-migration — 94% identical, 5 lines differ
How it starts
The opening of the file, as written. The whole thing — 53 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database: Create migration
You are a Postgres Expert who loves creating secure database schemas.
This project uses the migrations provided by the Supabase CLI.
Creating a migration file
Given the context of the user's message, create a database migration file inside the folder supabase/migrations/.
The file MUST following this naming convention:
The file MUST be named in the format YYYYMMDDHHmmss_short_description.sql with proper casing for months, minutes, and seconds in UTC time:
YYYY- Four digits for the year (e.g.,2024).MM- Two digits for the month (01 to 12).DD- Two digits for the day of the month (01 to 31).HH- Two digits for the hour in 24-hour format (00 to 23).mm- Two digits for the minute (00 to 59).ss- Two digits for the second (00 to 59).- Add an appropriate description for the migration.
For example:
20240906123045_create_profiles.sql
SQL Guidelines
Write Postgres-compatible SQL code for Supabase migration files that:
- Includes a header comment with metadata about the migration, such as the purpose, affected tables/columns, and any special considerations.
- Includes thorough comments explaining the purpose and expected behavior of each migration step.
- Write all SQL in lowercase.
- Add copious comments for any destructive SQL commands, including truncating, dropping, or column alterations.
- When creating a new table, you MUST enable Row Level Security (RLS) even if the table is intended for public access.
- When creating RLS Policies
- Ensure the policies cover all relevant access scenarios (e.g. select, insert, update, delete) based on the table's purpose and data sensitivity.
- If the table is intended for public access the policy can simply return
true. - RLS Policies should be granular: one policy for
select, one forinsertetc) and for each supabase role (anonandauthenticated). DO NOT combine Policies even if the functionality is the same for both roles. - Include comments explaining the rationale and intended behavior of each security policy
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.
- 9d ago First seen · 53 lines · 0 tokens per session scan A aa844e4fd5de
guidelines-for-writing-postgres-migrations-with-supabase-cli is a cursor rule published in the GitHub repository fumito-ito/mdcvalult (33 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 552 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 2026-08-30.
Other cursor rules, from other repositories
adapter-features
Database-specific features must be implemented in the specialized adapter only. Base adapters (postgres, mysql, etc.) must remain database-agnostic.
unit-tests-tdd
TDD required for behavior changes; ≥80% package coverage on touched packages; unit-test conventions.
integration-tests
Human-readable integration test requests; helpers vs httptest; suites/ vs per-DB placement.
postgresql
PostgreSQL production rules. Safe migrations, parameterized queries, TIMESTAMPTZ, proper indexing strategy.
postgresql
This guide defines the definitive best practices for writing clean, performant, and maintainable PostgreSQL SQL, focusing on modern conventions and avoiding common pitfalls.
database-access
A database access pattern that separates browser reads from server-side reads and writes when using Supabase. Supabase is a hosted PostgreSQL service with rules that can restrict which users may access rows.