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.
npx agentmods add skills/ahmadulhoq/agentskel/database-migrationnpx skills add ahmadulhoq/agentskel --skill database-migrationgit clone --depth 1 https://github.com/ahmadulhoq/agentskelWrote 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/ahmadulhoq/agentskel/database-migration)<a href="https://agentmods.dev/skills/ahmadulhoq/agentskel/database-migration"><img src="https://agentmods.dev/badge/skills/ahmadulhoq/agentskel/database-migration.svg" alt="Measured on agentmods" 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 | $0.00075 | $0.00880 |
| Opus 5 | $0.00037 | $0.00440 |
| Sonnet 5 | $0.00015 | $0.00176 |
| Haiku 4.5 | $0.00007 | $0.00088 |
Grade A, and why
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 2d 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 — 51 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Migration Standards
Step 1 — Identify the Migration System
- Find the existing migration directory/tool in use (grep for
migrations/,alembic/,db/migrate/, Room@Databaseversion, Core Data model versions,prisma/migrations/). - Match the existing naming/ordering convention exactly (timestamp prefix, sequence number, etc).
- Never introduce a new migration tool or pattern when one is already established.
Step 2 — Reversibility
- Every migration must have a working rollback path (
down/revert) unless the platform doesn't support one — state why in the migration if so. - Test the rollback, not just the forward migration.
Step 3 — Backward Compatibility (Zero-Downtime)
- Assume old application code may still run against the new schema during a rolling deploy.
- Additive first: add new columns/tables nullable or with a default; ship code that uses them; only drop/rename the old ones in a later migration once old code is fully retired.
- Never rename or drop a column/table in the same migration that introduces its replacement — split across separate migrations/deploys.
- Treat a rename as two migrations: add new, backfill, then remove old.
Step 4 — Data Safety
- Any destructive operation (
DROP COLUMN,DROP TABLE,TRUNCATE, a data-losing type change) requires explicit user confirmation before applying — flag it in the plan, don't just run it. - Batch large-table backfills; don't lock/rewrite the whole table in one transaction.
- Add
NOT NULLonly after backfilling existing rows — never add it without a default on a populated table.
Step 5 — Performance & Locking
- Check whether the target table is large or hot; avoid migrations that take table-level locks on production-sized tables without a concurrency-safe strategy (e.g.
CREATE INDEX CONCURRENTLYin Postgres, online DDL tools for MySQL). - Index creation/removal on hot paths must use the platform's concurrent/online option.
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.
- 2d ago First seen · 51 lines · 75 tokens per session scan A df4de8ab1504
database-migration is a skill published in the GitHub repository ahmadulhoq/agentskel (13 stars, last pushed 18d ago), licensed MIT. It adds 75 tokens to every session and 880 once invoked, about $0.0004 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 2026-09-02.
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