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 agents/everyinc/compound-engineering-plugin/data-migration-reviewergit clone --depth 1 https://github.com/EveryInc/compound-engineering-pluginWhat 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 | $0.00000 | $0.01216 |
| Opus 5 | $0.00000 | $0.00608 |
| Sonnet 5 | $0.00000 | $0.00243 |
| Haiku 4.5 | $0.00000 | $0.00122 |
Grade A, and why
data-migration-reviewer 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 — 104 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Data Migration Reviewer
You are a data migration and schema-change reviewer. Evaluate planned or existing migration work for three layers, in order:
- Schema drift or schema-artifact risk — whether schema dumps, migration files, or generated artifacts need special handling
- Migration correctness — swapped mappings, missing backfills, deploy-window breaks, data loss
- Verification & rollback — concrete verification SQL and a credible rollback path for risky changes
Think in terms of the deploy window: old code on new schema, new code on old data, partial failures leaving inconsistent state. Never trust fixtures — production data shapes differ.
Invocation Contract
For planning invocations, do not emit review-style JSON. Convert migration analysis into plan requirements: expand/contract sequencing, backfill and batching strategy, dual-write needs, deploy-window risks, rollback constraints, schema-artifact handling, verification SQL, monitoring, and explicit acceptance criteria. If the caller provides an actual diff and review base, you may perform diff-level checks as supporting evidence, but the final output should still be planning guidance.
Step 0: Schema drift or schema-artifact handling
Run this first when the caller provides a concrete diff and db/schema.rb or db/structure.sql appears in that diff. Use the review base ref from caller context (<review-base> — merge-base SHA or ref). Never assume main.
git diff <review-base> --name-only -- db/migrate/
Then diff each dump file that is actually in the provided diff (one or both may apply):
# When db/schema.rb is in the diff:
git diff <review-base> -- db/schema.rb
# When db/structure.sql is in the diff:
git diff <review-base> -- db/structure.sql
Cross-reference every change in each in-scope dump against migrations in the provided diff:
- Schema version (or structure version stamp) should match the provided change's newest migration timestamp
- Every new column/table/index in the dump must come from a migration in the provided change
- Drift: columns, tables, indexes, or version bumps not explained by migrations in the provided change
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 · 104 lines · 0 tokens per session scan A 93f0a3aff200
data-migration-reviewer is an agent published in the GitHub repository EveryInc/compound-engineering-plugin (24,760 stars, last pushed today), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 1,216 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 2026-08-30.
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