pREST is an API service that creates REST and Model Context Protocol endpoints for an existing or new PostgreSQL database, covering database operations, custom SQL routes, authentication, access control, and read-only MCP access. Developers use it to expose PostgreSQL data without writing a separate backend. The catalogue entries provide rules, skills, and instructions for using pREST.
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/prest/prestWrote 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/prest/prest/unit-tests-tdd)<a href="https://agentmods.dev/rules/prest/prest/unit-tests-tdd"><img src="https://agentmods.dev/badge/rules/prest/prest/unit-tests-tdd/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/prest/prest/unit-tests-tdd"><img src="https://agentmods.dev/badge/rules/prest/prest/unit-tests-tdd.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 | $0.00375 | $0.00375 |
| Opus 5.5 | $0.00150 | $0.00150 |
| Sonnet 5.5 | $0.00075 | $0.00075 |
| Haiku 4.5 | $0.00038 | $0.00038 |
Grade A, and why
unit-tests-tdd 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.
What it actually says
Unit Tests & TDD
TDD (behavior changes)
For adding or changing behavior: failing unit test first → implement → refactor. Do not land production code without a red→green cycle.
Coverage bar
Unit tests for packages under change must cover ≥80% of that package’s existing code (not only new lines). Verify before done:
go test -timeout 30s -race -cover ./path/to/package/...
# or full unit suite (writes coverage.out):
make test-unit
Fail the task if package coverage is under 80%.
Placement & isolation
- Co-located
<source>_test.go(e.g.config.go→config_test.go) - Mock ports via
adapters/mockgen/; never live DB orpostgres.Load()in unit tests - Outside
adapters/postgres/, mock ports — not concrete postgres types
Parallelism
- Prefer
t.Parallel()when safe (no shared mutable state / ordering) - Never with
t.Setenv, mutatedconfig.Load(),SetDBConnectForTest, or shared globals
Controllers / HTTP
TDD unit tests do not replace E2E. Every behavior change MUST also ship an
integration test — this is not optional for controller/HTTP-adjacent code, it
is the gate that catches a sibling code path a mocked unit test structurally
cannot see (e.g. a second query-param builder reusing weaker validation than
the one under test). See integration-tests.mdc (MUST section) and skill
prest-integration-tests.
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 · 45 lines · 375 tokens per session scan A adccb40c4efb
unit-tests-tdd is a cursor rule published in the GitHub repository prest/prest (4,624 stars, last pushed yesterday), licensed MIT. It adds 375 tokens to every session, about $0.0015 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
test-database-limitations
Test databases created via withDevDatabase() from @repo/test-utils use pglite (an in-memory PostgreSQL implementation via @prisma/dev). Pglite does not support PostgreSQL extensions like pgvector, pgtrgm, etc.
sql-orm-client-whole-shape-assertions
Prefer whole-result-shape assertions with explicit select projections in sql-orm-client tests.
go-service-errors
Go service error translation, nullable TIMESTAMPTZ scans, history, and side effects.
database-interaction-best-practices
Best practices when interacting with databases in backend Go code.
test-database-limitations
Test databases created via withDevDatabase() from @prisma-next/test-utils use pglite (an in-memory PostgreSQL implementation via @prisma/dev). Pglite does not support PostgreSQL extensions like pgvector, pgtrgm, etc.
20-testing-generated-and-structure
Testing expectations, generated-file boundaries, and CLI structure contract.