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 skills add tranhieutt/software_development_department --skill sql-optimization-patternsgit clone --depth 1 https://github.com/tranhieutt/software_development_departmentWrote 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/skills/tranhieutt/software_development_department/sql-optimization-patterns)<a href="https://agentmods.dev/skills/tranhieutt/software_development_department/sql-optimization-patterns"><img src="https://agentmods.dev/badge/skills/tranhieutt/software_development_department/sql-optimization-patterns/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/skills/tranhieutt/software_development_department/sql-optimization-patterns"><img src="https://agentmods.dev/badge/skills/tranhieutt/software_development_department/sql-optimization-patterns.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 | $0.00038 | $0.00711 |
| Opus 5 | $0.00019 | $0.00356 |
| Sonnet 5 | $0.00008 | $0.00142 |
| Haiku 4.5 | $0.00004 | $0.00071 |
Grade A, and why
sql-optimization-patterns 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 8d 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 — 99 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SQL Optimization Patterns
Query optimization, indexing, and performance tuning for PostgreSQL, MySQL, and SQLite.
Index Strategy
When to Create Index
```sql -- High selectivity columns (many unique values) CREATE INDEX idx_orders_user_id ON orders(user_id);
-- Composite index: order matters (equality first, then range) CREATE INDEX idx_orders_user_date ON orders(user_id, created_at DESC);
-- Covering index (includes all needed columns) CREATE INDEX idx_orders_covering ON orders(user_id, status) INCLUDE (total, created_at); ```
When NOT to Index
- Low cardinality columns (boolean, status with few values)
- Small tables (< 1000 rows)
- Write-heavy tables with rare reads
Query Patterns
Avoid SELECT *
```sql -- Bad SELECT * FROM orders WHERE user_id = 1;
-- Good (select only needed columns) SELECT id, total, status FROM orders WHERE user_id = 1; ```
Avoid N+1 (use JOIN or subquery)
```sql -- Bad: N+1 queries from application -- Good: Single query with JOIN SELECT o.id, o.total, u.name FROM orders o JOIN users u ON o.user_id = u.id WHERE o.status = 'pending'; ```
Pagination (keyset, not OFFSET)
```sql -- Bad: OFFSET scans all skipped rows SELECT * FROM orders ORDER BY id LIMIT 20 OFFSET 10000;
-- Good: Keyset pagination SELECT * FROM orders WHERE id > 10000 ORDER BY id LIMIT 20; ```
EXPLAIN ANALYZE
```sql EXPLAIN ANALYZE SELECT * FROM orders WHERE user_id = 1 AND status = 'pending'; ```
Read output:
- Seq Scan = missing index
- Index Scan = good
- Nested Loop with high row count = check join strategy
Schema Anti-Patterns
| Anti-Pattern | Problem | Fix |
|---|---|---|
| EAV (Entity-Attribute-Value) | No type safety, slow queries | Use JSONB or proper columns |
| God table | Too many columns | Normalize into related tables |
| No constraints | Data integrity issues | Add CHECK, FK, UNIQUE constraints |
| String dates | Sorting/filtering issues | Use TIMESTAMP type |
Connection Pooling
What ships with it
1 file beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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.
- 8d ago First seen · 99 lines · 38 tokens per session scan A dac285a7bf2b
sql-optimization-patterns is a skill published in the GitHub repository tranhieutt/software_development_department (72 stars, last pushed 4mo ago), licensed MIT. It adds 38 tokens to every session and 711 once invoked, about $0.0002 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 2026-09-03.
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