What is db-migration?

A guided procedure for changing a PostgreSQL database structure safely. It updates the schema definition, generates a migration, reviews the resulting SQL, applies it locally, and runs tests.

Use it for changes under src/db/, such as adding or changing tables, columns, foreign keys, timestamps, money fields, or enums.

It prevents edits to the database's permanent migration history and helps catch accidental data loss, missing indexes, or incorrect types before applying a change.

db-migration — Skill for Claude Code by nikandr-surkov

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.

Any agent

npx skills add nikandr-surkov/ai-saas-starter --skill db-migration

Clone the repo

git clone --depth 1 https://github.com/nikandr-surkov/ai-saas-starter

Made for: Claude Code.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/nikandr-surkov/ai-saas-starter/db-migration/github.svg)](https://agentmods.dev/skills/nikandr-surkov/ai-saas-starter/db-migration)

Your own site

<a href="https://agentmods.dev/skills/nikandr-surkov/ai-saas-starter/db-migration"><img src="https://agentmods.dev/badge/skills/nikandr-surkov/ai-saas-starter/db-migration/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/nikandr-surkov/ai-saas-starter/db-migration"><img src="https://agentmods.dev/badge/skills/nikandr-surkov/ai-saas-starter/db-migration.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 391 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

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.

Model	Per session	Once invoked
Fable 5.1	$0.00034	$0.00391
Opus 5	$0.00017	$0.00196
Sonnet 5	$0.00007	$0.00078
Haiku 4.5	$0.00003	$0.00039

Measured 9d ago against content hash 0f06f9feb133, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

db-migration 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.

.claude/skills/db-migration/SKILL.md · 38 lines

What it actually says

Database migration

Applied migrations are immutable history. This skill exists so nobody ever "just edits the SQL file".

Steps

Ask the user first. Schema changes are on the ASK FIRST list in AGENTS.md. Describe the change and why.
Edit src/db/schema.ts only. Conventions:
- Every foreign key gets an index.
- Timestamps: createdAt with defaultNow(), timezone-aware.
- Money in integer cents; credits in integers.
- Enums via pgEnum, named <table>_<column>.
Generate: pnpm db:generate. Never write migration SQL by hand.
Read the generated file in drizzle/. Confirm: no unintended DROP, correct column types/defaults, indexes present. Column renames often generate drop+create — if data must survive, say so and write the migration plan out for the user before applying.
Apply locally: pnpm db:migrate (Postgres running via docker compose up -d).
Run pnpm test — the ledger suite will catch schema drift in credit tables.
Commit src/db/schema.ts and the new drizzle/ files together.

Never

Edit or delete an existing file in drizzle/.
Run drizzle-kit push against anything but a throwaway local DB — this repo uses generated, committed migrations.
Touch credit_transactions semantics (signed integer amounts, UNIQUE idempotencyKey) without reading .claude/rules/billing.md.

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.

9d ago First seen · 38 lines · 34 tokens per session scan A 0f06f9feb133

Subscribe to this mod's changes

db-migration is a skill published in the GitHub repository nikandr-surkov/ai-saas-starter (19 stars, last pushed 1mo ago), licensed MIT. It adds 34 tokens to every session and 391 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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