migration-safety skillA
migration-safety is agent-read markdown (skill) from jakeselby/agent-harness: Write, review or apply a database schema migration without destroying data. Use for any task that creates or modifies a migration file (Alembic, Prisma, Django, Rails, Flyway, raw SQL), and before applying one to a shared environment..
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns the same grade.
What the file says
# Migration safety ## Treat every environment as production Staging and demo environments hold real data more often than anyone admits, and a migration that destroys data in staging demonstrates that the same operation would run in production. There is no "it's just staging" exception. **Never write a migration that could silently destroy existing data.** ## Destructive operations — stop and surface to the human Do not generate these autonomously. Describe what you intend and why, and wait for confirmation before writing the file: - `DROP TABLE`, `DROP COLUMN`, `TRUNCATE` — destroys rows or values permanently. - `ALTER COLUMN … TYPE` with a lossy cast — the database rewrites the column; values that cannot be cast are lost. - Removing `NOT NULL` and then dropping the column — same as above. - `DELETE FROM` inside a migration — data loss with no recovery short of a backup. ## Safe patterns **Adding a column.** Add it nullable first, even if the final intent is `NOT NULL`. Backfill in a separate migration or deploy step. Add the constraint only after the backfill is confirmed. Three small migrations beat one that rewrites data and adds a constraint at once. …
Read the whole file at its exact version.
How to install
mdr add jakeselby/agent-harness/migration-safety@git:20260919.6cf18f7mdr add jakeselby/agent-harness/migration-safety@sha256:0f1f08cd4a363147Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_l5o6ysxbegclxzqe)
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Versions
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (3759 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
jakeselby/agent-harness · 17 stars · license MIT · pushed 2026-09-25 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_l5o6ysxbegclxzqe GET https://markdownregistry.com/api/v1/resolve?ref=jakeselby/agent-harness/migration-safety GET https://markdownregistry.com/api/v1/blob/0f1f08cd4a36314700bb4e8f9bf6f183c449577108d11d9e31e9bb2053c337c7
Your agent does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.