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 JakubMikolajek/codex-skills-collection --skill sql-and-databasegit clone --depth 1 https://github.com/JakubMikolajek/codex-skills-collectionWrote 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/jakubmikolajek/codex-skills-collection/sql-and-database)<a href="https://agentmods.dev/skills/jakubmikolajek/codex-skills-collection/sql-and-database"><img src="https://agentmods.dev/badge/skills/jakubmikolajek/codex-skills-collection/sql-and-database/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/jakubmikolajek/codex-skills-collection/sql-and-database"><img src="https://agentmods.dev/badge/skills/jakubmikolajek/codex-skills-collection/sql-and-database.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00093 | $0.11071 |
| Opus 5 | $0.00046 | $0.05535 |
| Sonnet 5 | $0.00019 | $0.02214 |
| Haiku 4.5 | $0.00009 | $0.01107 |
Grade A, and why
sql-and-database 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 9d 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 — 1,231 lines — stays where its author put it; the contents beside it link to each section on GitHub.
SQL & Database Engineering
This skill provides standards, patterns, and procedures for database schema design, writing performant SQL, query debugging, and database engineering best practices. It is database-engine-agnostic with notes on engine-specific behavior where critical.
Guiding Principles
| Principle | Application |
|---|---|
| Data Integrity First | Enforce constraints at the database level (NOT NULL, UNIQUE, FK, CHECK). Never rely solely on application-level validation. |
| Least Privilege | Database users/roles should have only the permissions they need. Application connections should never use the superuser account. |
| Explicit Over Implicit | Always specify column lists in SELECT, INSERT, and JOIN clauses. Avoid SELECT * in production code. |
| Measure Before Optimising | Use EXPLAIN ANALYZE to identify actual bottlenecks before adding indexes or restructuring queries. |
| Schema as Code | All schema changes go through versioned migration files. Never modify production schemas manually. |
1. Database Schema Architecture Design
Naming Conventions
| Element | Convention | Example |
|---|---|---|
| Tables | snake_case, plural nouns |
order_items, user_addresses |
| Columns | snake_case |
first_name, created_at |
| Primary keys | id (preferred) or <table_singular>_id |
id, user_id |
| Foreign keys | <referenced_table_singular>_id |
user_id, order_id |
| Indexes | idx_<table>_<columns> |
idx_orders_user_id_status |
| Unique constraints | uq_<table>_<columns> |
uq_users_email |
| Check constraints | chk_<table>_<description> |
chk_orders_total_positive |
| Junction/pivot tables | <table1>_<table2> (alphabetical) |
products_tags, roles_users |
Standard Columns
Every table MUST include:
CREATE TABLE orders (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(), -- or BIGSERIAL for auto-increment
-- ... domain columns ...
created_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT NOW(),
updated_at TIMESTAMP WITH TIME ZONE NOT NULL DEFAULT NOW()
);
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.
- 9d ago First seen · 1,231 lines · 93 tokens per session scan A 06e4b43aa719
sql-and-database is a skill published in the GitHub repository JakubMikolajek/codex-skills-collection (5 stars, last pushed 3d ago), licensed MIT. It adds 93 tokens to every session and 11,071 once invoked, about $0.0005 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 2026-08-31.
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