Create database migration

A guide for changing the structure of Ghost's MySQL database through a database migration. A migration is a tracked change that adds or alters tables, columns, or settings.

In plain words
What is it for?
Use it when adding, removing, or renaming database tables or columns, adding settings, or making another schema change in Ghost.
Why use it?
It provides the required project process for creating the migration, updating Ghost's schema definition, and checking that the change works safely.

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/tryghost/ghost/create-database-migration
Any agent
npx skills add TryGhost/Ghost --skill create-database-migration
Clone the repo
git clone --depth 1 https://github.com/TryGhost/Ghost

Made for: Claude Code, Codex.

Per session 146 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 715 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 $0.00146 $0.00715
Opus 5 $0.00073 $0.00358
Sonnet 5 $0.00029 $0.00143
Haiku 4.5 $0.00015 $0.00072

Measured yesterday against content hash ea7f7c12abb3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Create database 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 yesterday.

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.

.agents/skills/create-database-migration/SKILL.md · 34 lines

How it starts

The opening of the file, as written. The whole thing — 34 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Create Database Migration

Read the canonical human guidance in docs/practices/database-migrations.md before making a migration. This skill is the executable checklist that accompanies it.

Instructions

  1. Create a new, empty migration file: cd ghost/core && pnpm migrate:create <kebab-case-slug>. IMPORTANT: do not create the migration file manually; always use this script to create the initial empty migration file. The slug must be kebab-case (e.g. add-column-to-posts).
  2. The above command will create a new directory in ghost/core/core/server/data/migrations/versions if needed, create the empty migration file with the appropriate name, and bump the core and admin package versions to RC if this is the first migration after a release.
  3. Update the migration file with the changes you want to make in the database, following the existing patterns in the codebase. Where appropriate, prefer to use the utility functions in ghost/core/core/server/data/migrations/utils/*.
  4. Update the schema definition file in ghost/core/core/server/data/schema/schema.js, and make sure it aligns with the latest changes from the migration.
  5. Test the migration manually: cd ghost/core && pnpm knex-migrator migrate --v {version directory} --force
  6. Roll the migration back to test down(): cd ghost/core && pnpm knex-migrator rollback --v {previous version} --force, then migrate forward again.
  7. Run the migration integration test, which covers initialization, rollback, forward migration, and idempotency: cd ghost/core && pnpm test:single test/integration/migrations/migration.test.js. Migrations must pass the database-backed suites against both MySQL and SQLite.
  8. If adding or dropping a table, update ghost/core/core/server/data/exporter/table-lists.js as appropriate. The consistency assertion in ghost/core/test/unit/server/data/exporter/index.test.js checks that every schema table is classified in the exporter lists.
  9. Run the focused exporter unit test when the table lists change: cd ghost/core && pnpm test:single test/unit/server/data/exporter/index.test.js.
  10. Run the schema integrity test, and update the hash: cd ghost/core && pnpm test:single test/unit/server/data/schema/integrity.test.js
  11. Run unit tests in Ghost core, and iterate until they pass: cd ghost/core && pnpm test:unit

Read the full file on GitHub · 34 lines

Files

What ships with it

2 files 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. yesterday First seen · 34 lines · 146 tokens per session scan A ea7f7c12abb3

Subscribe to this mod's changes

Create database migration is a skill published in the GitHub repository TryGhost/Ghost (55,095 stars, last pushed today), licensed MIT. It adds 146 tokens to every session and 715 once invoked, about $0.0007 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.