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/hamzaamjad/cursor-rulesWrote 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/hamzaamjad/cursor-rules/202-database-selection)<a href="https://agentmods.dev/rules/hamzaamjad/cursor-rules/202-database-selection"><img src="https://agentmods.dev/badge/rules/hamzaamjad/cursor-rules/202-database-selection/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/hamzaamjad/cursor-rules/202-database-selection"><img src="https://agentmods.dev/badge/rules/hamzaamjad/cursor-rules/202-database-selection.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 | $0.00000 | $0.00707 |
| Opus 5.5 | $0.00000 | $0.00283 |
| Sonnet 5.5 | $0.00000 | $0.00141 |
| Haiku 4.5 | $0.00000 | $0.00071 |
Grade A, and why
202-database-selection 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 — 69 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Selection Checklist
-
Purpose: To ensure appropriate database technology selection based on access patterns, concurrency requirements, and existing infrastructure. Research shows: Wrong database selection causes 60% of performance issues and 40% of scaling failures.
-
Requirements: When proposing or implementing database solutions, evaluate against these criteria:
Tree of Thoughts Database Evaluation
Generate and compare 3 database options using quantitative scoring:
Score = (Performance × 0.3) + (Scalability × 0.3) + (Operational × 0.2) + (Cost × 0.2)
Concurrency Evaluation
- Write Concurrency: Will multiple agents/services write simultaneously?
- Score: 0-10 based on expected concurrent writers
- PostgreSQL: 10 (excellent), DuckDB: 1 (single-writer only)
- Read Concurrency: Will multiple agents/services read simultaneously?
- Score: 0-10 based on expected concurrent readers
- Connection Limits: What are the connection pool requirements?
- Quantify: connections_needed / max_connections
- Transaction Isolation: What level of ACID compliance is needed?
- Strict ACID: +3 points for PostgreSQL
- Eventual consistency OK: +3 points for NoSQL options
Performance Requirements
- Write Performance: Expected writes per second?
- Read Performance: Expected queries per second?
- Data Volume: Expected data size over 1 year?
- Query Complexity: Simple lookups vs complex analytics?
Operational Considerations
- Existing Infrastructure: What databases are already deployed?
- Migration Complexity: How difficult to migrate from current state?
- Operational Overhead: Additional services to maintain?
- Backup/Recovery: Built-in or requires additional tooling?
Mirror-Specific Context
Current database infrastructure:
- PostgreSQL + TimescaleDB: Primary database for time-series data (handles concurrent writes)
- DuckDB: Analytics engine for read-only complex queries (single-writer limitation)
- ChromaDB: Vector database for semantic memory
- Redis: Cache and message broker
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 · 69 lines · 0 tokens per session scan A ca133046a8e2
202-database-selection is a cursor rule published in the GitHub repository hamzaamjad/cursor-rules (2 stars, last pushed 1y ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 707 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 2026-08-31.
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