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.
git clone --depth 1 https://github.com/netlify/context-and-toolsWrote 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/rules/netlify/context-and-tools/netlify-database-local-dev)<a href="https://agentmods.dev/rules/netlify/context-and-tools/netlify-database-local-dev"><img src="https://agentmods.dev/badge/rules/netlify/context-and-tools/netlify-database-local-dev/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/rules/netlify/context-and-tools/netlify-database-local-dev"><img src="https://agentmods.dev/badge/rules/netlify/context-and-tools/netlify-database-local-dev.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 | $0.00012 | $0.00657 |
| Opus 5.5 | $0.00005 | $0.00263 |
| Sonnet 5.5 | $0.00002 | $0.00131 |
| Haiku 4.5 | $0.00001 | $0.00066 |
Grade A, and why
netlify-database-local-dev 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 1mo 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 — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Local development
netlify dev runs Netlify Database locally against an embedded Postgres-compatible instance — no remote connection, and no risk of writing to production data. Data persists under .netlify/ in the project directory.
Add .netlify to .gitignore if it isn't already.
Running the app
netlify dev
The database is available to functions, edge functions, framework server routes, and any code that calls getDatabase() or getConnectionString() — same API as production.
For Vite-based projects, install @netlify/vite-plugin so the dev server can connect to the local database without launching netlify dev as a wrapper.
Applying migrations locally
netlify dev does not apply migrations automatically — that's the deploy's job for hosted databases. Locally, you run them yourself:
netlify database migrations apply # apply all pending
netlify database migrations apply --to <name> # apply up to a specific migration
This targets the local dev DB only. Generating migrations from a Drizzle schema doesn't connect to a database, so plain npx drizzle-kit generate works — no wrapper needed.
Do not run drizzle-kit migrate or drizzle-kit push against NETLIFY_DB_URL in any context — Netlify applies migrations to hosted databases (preview branches and production) automatically on deploy. See references/migrations.md.
Inspecting the local DB
netlify database status # applied/pending state
netlify database connect # interactive REPL
netlify database connect --query "SELECT * FROM items" # one-shot query
netlify database connect --json # connection details as JSON
For tools that need a bare connection string (psql, pgAdmin, DataGrip, TablePlus), pipe connect --json through jq:
psql "$(netlify database connect --json | jq -r .connection_string)"
Resetting local data
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.
- 1mo ago First seen · 63 lines · 12 tokens per session scan A df304ec9a0a2
netlify-database-local-dev is a cursor rule published in the GitHub repository netlify/context-and-tools (41 stars, last pushed 2d ago), licensed MIT. It adds 12 tokens to every session and 657 once invoked, about $0.0000 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 2026-08-30.
Other cursor rules, from other repositories
adapter-features
Database-specific features must be implemented in the specialized adapter only. Base adapters (postgres, mysql, etc.) must remain database-agnostic.
unit-tests-tdd
TDD required for behavior changes; ≥80% package coverage on touched packages; unit-test conventions.
planning-and-delegation
Plan every task first, parallelise independent work, and staff each task with the cheapest model that can do it well.
integration-tests
Human-readable integration test requests; helpers vs httptest; suites/ vs per-DB placement.
postgresql
PostgreSQL production rules. Safe migrations, parameterized queries, TIMESTAMPTZ, proper indexing strategy.
postgresql
This guide defines the definitive best practices for writing clean, performant, and maintainable PostgreSQL SQL, focusing on modern conventions and avoiding common pitfalls.