Borrowing it
Nothing to install: this file belongs to cardstack/boxel. 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/cardstack/boxel/main/.claude/skills/postgres-migrations/SKILL.mdgit clone --depth 1 https://github.com/cardstack/boxelWrote 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/cardstack/boxel/postgres-migrations)<a href="https://agentmods.dev/skills/cardstack/boxel/postgres-migrations"><img src="https://agentmods.dev/badge/skills/cardstack/boxel/postgres-migrations/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/cardstack/boxel/postgres-migrations"><img src="https://agentmods.dev/badge/skills/cardstack/boxel/postgres-migrations.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 | $0.00134 | $0.01256 |
| Opus 5.5 | $0.00054 | $0.00502 |
| Sonnet 5.5 | $0.00027 | $0.00251 |
| Haiku 4.5 | $0.00013 | $0.00126 |
Grade A, and why
postgres-migrations 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 5d 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 — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Postgres migrations — the two-phase system
packages/postgres/ migrations are split into two directories, each with its own
node-pg-migrate tracking table, because a destructive schema change applied
during a rolling deploy breaks the previous code revision while it is still
serving (old tasks query a column the migration just dropped).
| Directory | Tracking table | When it runs in a deploy | For |
|---|---|---|---|
migrations/ |
migrations |
pre-deploy (migrate-db job) |
additive, backward-compatible changes |
migrations-removal/ |
migrations_removal |
post-deploy (migrate-db-remove job), gated on the realm-server rollout reaching stability so old tasks have drained |
destructive changes |
Which directory?
Ask: does the migration's up() remove or rename something the currently
deployed code still reads? If yes → migrations-removal/.
- Additive →
migrations/:addColumn,createTable, new index, backfill, dual-write. Safe for old code to run against. - Destructive →
migrations-removal/:dropColumn/dropColumns/dropTable/renameColumn/renameTable, and the raw-SQL equivalents (pgm.sql('ALTER TABLE ... DROP COLUMN ...'),RENAME). Also anything that tightens a contract the old code depends on (e.g. addingNOT NULLto a column old code doesn't populate, narrowing a type).
The standard expand/contract pattern spans two releases: release N adds the new shape and stops reading the old one (additive migration + code); release N+1 drops the old shape (removal migration). Never ship the drop in the same release that stops reading it unless you are certain no old task will run against the new schema.
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.
- 5d ago First seen · 92 lines · 134 tokens per session scan A 546fb35c0c08
postgres-migrations is a skill published in the GitHub repository cardstack/boxel (27 stars, last pushed today), licensed MIT. It adds 134 tokens to every session and 1,256 once invoked, about $0.0005 per session on Opus 5.5. 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 2026-10-21.
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