Run Database Migration

Applies pending Supabase migrations to the local or production database. This skill is strictly additive — it only applies new migrations and NEVER resets, truncates, or drops existing data.

Safety rules — READ BEFORE PROCEEDING

You MUST follow every rule below. No exceptions.

1. NEVER run supabase db reset, supabase db reset --linked, or any command that drops/recreates the database.
2. NEVER run DROP TABLE, DROP SCHEMA, TRUNCATE, or DELETE FROM against any table unless it is explicitly part of the migration SQL the user has already reviewed.
3. NEVER pass --linked to db reset. There is no safe use of db reset in this skill.
4. NEVER modify or overwrite an existing migration file. Migrations that have already been applied are immutable.
5. ALWAYS show the user the exact SQL that will run before applying it.
6. ALWAYS confirm with the user before applying migrations to production.
7. NEVER rely on --linked for remote targets. The currently linked project may belong to a different environment than the one the user asked for. Always target the database explicitly via --db-url "$POSTGRES_POOLER_URL" (sourced from the env file for the requested environment).
8. If anything looks destructive or risky, STOP and ask the user before continuing.

Parameters

The user specifies the environment as an argument: /migrate local, /migrate dev, or /migrate prod. If not provided, ask which environment.

• local → env file: .env.supabase
• dev → env file: .env.cloud.dev
• prod → env file: .env.cloud

Steps

1. Source environment variables

set -a && source <env-file> && set +a

2. Check for pending migrations

List which migrations have already been applied and which are pending.

For local:

npx supabase migration list --workdir deployment --local

For dev or prod, target the env's database directly via --db-url — never rely on --linked:

npx supabase migration list --workdir deployment --db-url "$POSTGRES_POOLER_URL"

POSTGRES_POOLER_URL comes from the env file sourced in step 1; it embeds the password and project host, so this command is unambiguous about which database it hits regardless of what supabase link last pointed at.

Show the user the list of pending (not yet applied) migrations.

3. Review migration SQL

For each pending migration, read the file from deployment/supabase/migrations/ and display its contents to the user. Summarise what the migration does. Flag anything that looks destructive (drops, truncates, deletes) and ask the user to confirm.

4. Apply the migrations

For local — apply pending migrations to the running local Supabase instance:

npx supabase migration up --workdir deployment --local

For dev or prod — push pending migrations directly to the env's database via --db-url:

npx supabase db push --workdir deployment --db-url "$POSTGRES_POOLER_URL" --include-all

Do NOT use --linked for remote pushes. Targeting --db-url from the just-sourced env file guarantees the push lands on the env the user asked for, even if supabase link was last run against a different project.

Production only: Before running db push, ask the user for explicit confirmation one more time. Show them exactly which migrations will be applied.

5. Verify

After applying, re-run the migration list command from step 2 and confirm all migrations now show as applied. Report the result to the user.

Creating a new migration

If the user wants to create a new migration (not just apply existing ones):

1. Generate a timestamped migration file:

npx supabase migration new <migration_name> --workdir deployment

2. Open the newly created file for the user to write the SQL.
3. After the SQL is written, follow steps 2–5 above to review and apply it.

Important notes

• Migrations live in deployment/supabase/migrations/ and follow the naming convention YYYYMMDDhhmmss_description.sql.
• For local development, Supabase must already be running (npx supabase start --workdir deployment/).
• Each cloud env file (.env.cloud.dev, .env.cloud) defines POSTGRES_POOLER_URL for its project. The skill targets that URL via --db-url, so there is no supabase link step and no risk of pushing to the wrong project because the link points elsewhere. If a future env file is missing this var, surface that to the user instead of falling back to --linked.
• All command output should be redirected to files when it may be verbose. Do NOT use tee.
• This skill is only for schema migrations. For seeding runtime config (e.g. combat cron), use the reset-world or deploy skills instead.