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 rules/nerds-odd-e/doughnut/db-migrationgit clone --depth 1 https://github.com/nerds-odd-e/doughnutWhat 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 | $0.00023 | $0.01638 |
| Opus 5 | $0.00012 | $0.00819 |
| Sonnet 5 | $0.00005 | $0.00328 |
| Haiku 4.5 | $0.00002 | $0.00164 |
Grade A, and why
db-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 — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Migration Guidelines
When to Use This Rule
Use this rule when:
- Creating new database migrations
- Modifying database schema
- Understanding migration file naming conventions
- Working with Flyway migrations
- Troubleshooting migration issues
- Versioning database changes
- Squashing / collapsing historical migrations into the baseline
Migration Tool
The project uses Flyway for database migrations, configured in Spring Boot.
Migration Files Location
- SQL migrations:
backend/src/main/resources/db/migration/ - Java migrations:
backend/src/main/java/db/migration/ - Files follow the naming convention:
V{version}__{description}.sql(or.java)- Example:
V300000301__rename_a_column.sql(version must exceed300000300)
- Example:
Version Numbering
- Versions use a numerical format
The project uses versioned files named V{number}__{description}.sql. The current full application DDL is collapsed into V100000000__baseline.sql; V300000300__db_migration_placeholder.sql is a placeholder for the next migration.
New migrations need to use a greater version number than 300000300.
Migration Process
- Migrations run automatically when the application starts (non-test environments)
- Non-test startup runs
flyway.repair()thenflyway.migrate()(FlyWayFreeVersionRealMigration).repair()is what makes squashing safe on existing databases (checksum realign + remove history for deleted files). - For unit tests, DB migration is included in the test command (see
backend-developmentrule for test execution)
Migration file structure
V100000000__baseline.sqlholds the collapsed full DDL (fresh installs).V300000300__db_migration_placeholder.sqlis the tail placeholder; add new migrations with a higher version.- Each new file after that should contain one atomic change (create/alter/rename/drop as needed).
Best Practices:
- Each migration should be reversible when possible
- Migrations are version controlled and should never be modified once committed (except the intentional baseline content replace during a squash — see below)
- New changes should always be added as new migration files
- Clear, descriptive names should be used for migration files to indicate their purpose
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 · 95 lines · 23 tokens per session scan A dd1f652f39da
db-migration is a cursor rule published in the GitHub repository nerds-odd-e/doughnut (49 stars, last pushed 2d ago), licensed MIT. It adds 23 tokens to every session and 1,638 once invoked, about $0.0001 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 2026-08-30.
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