Borrowing it
Nothing to install: this file belongs to pyramidheadshark/claude-scaffold. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/pyramidheadshark/claude-scaffold/main/.claude/skills/database-migration-safety/SKILL.mdgit clone --depth 1 https://github.com/pyramidheadshark/claude-scaffoldWrote 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/skills/pyramidheadshark/claude-scaffold/database-migration-safety)<a href="https://agentmods.dev/skills/pyramidheadshark/claude-scaffold/database-migration-safety"><img src="https://agentmods.dev/badge/skills/pyramidheadshark/claude-scaffold/database-migration-safety/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/skills/pyramidheadshark/claude-scaffold/database-migration-safety"><img src="https://agentmods.dev/badge/skills/pyramidheadshark/claude-scaffold/database-migration-safety.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 | $0.00729 |
| Opus 5 | $0.00000 | $0.00365 |
| Sonnet 5 | $0.00000 | $0.00146 |
| Haiku 4.5 | $0.00000 | $0.00073 |
Grade A, and why
database-migration-safety 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.
How it starts
The opening of the file, as written. The whole thing — 72 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Skill: Database Migration Safety
When to Load
Auto-load when: working with Alembic, raw SQL migrations, schema changes, migrations/ directory, or *.sql files. Triggers on alembic, migration, upgrade, downgrade, schema, ALTER TABLE (≥2 keywords).
Core Rules
Every migration must satisfy these requirements before alembic upgrade head runs:
- Reversible —
downgrade()must be implemented and tested.passis not acceptable. - Staged — run against a staging/dev database before production.
- Piloted — for data migrations over 1M rows, run on a 1% sample first.
- Snapshotted — take a DB snapshot/backup before any destructive operation (DROP, ALTER with data loss risk).
Pre-Migration Checklist
Before proposing or executing any migration:
[ ] downgrade() is implemented (not pass)
[ ] Migration tested on staging DB
[ ] For tables > 100k rows: migration is non-locking (CONCURRENT index, batched updates)
[ ] No data loss without explicit acknowledgment: DROP COLUMN, TRUNCATE, type narrowing
[ ] --autogenerate output reviewed manually (it misses: renames, indexes, check constraints)
[ ] Rollback plan documented: "If this fails in prod, run: alembic downgrade -1"
Anti-Patterns — Block on Detection
| Anti-Pattern | Risk | Required Action |
|---|---|---|
downgrade() is pass |
Irreversible migration | Implement downgrade or get explicit sign-off |
DROP COLUMN without nullable grace period |
Data loss on rollback | Add nullable=True first, drop in next release |
--autogenerate applied without review |
Silent schema drift | Always diff before apply |
alembic upgrade head in prod without staging |
Broken prod schema | Require staging run first |
Locking ALTER TABLE on large table |
Table lock, downtime | Use CREATE INDEX CONCURRENTLY, batched UPDATE |
| Migration touches multiple unrelated models | Hard to rollback atomically | Split into separate migrations |
Alembic-Specific Guidance
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.
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 · 72 lines · 0 tokens per session scan A b07e0fb5d70f
database-migration-safety is a skill published in the GitHub repository pyramidheadshark/claude-scaffold (4 stars, last pushed 4mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 729 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 2026-08-31.
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