Rules for designing and checking database indexes in PostgreSQL, MySQL, and SQL Server. A database index is an extra structure that can make searches faster, but it also uses storage and can slow down writes.

Creating, changing, or auditing indexes; choosing column order; using covering or INCLUDE columns; diagnosing slow queries; and finding poor index designs.

It helps choose index columns and ordering that improve query speed without adding unnecessary maintenance and memory costs.

How 0xmichalis/agent-rules configures Claude Code

Reuse

Borrowing it

Nothing to install: this file belongs to 0xmichalis/agent-rules. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file

curl -O https://raw.githubusercontent.com/0xmichalis/agent-rules/main/.claude/skills/sql-indexes/SKILL.md

Clone the repo

git clone --depth 1 https://github.com/0xmichalis/agent-rules

Made for: Claude Code.

Wrote 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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/0xmichalis/agent-rules/sql-indexes/github.svg)](https://agentmods.dev/skills/0xmichalis/agent-rules/sql-indexes)

Your own site

<a href="https://agentmods.dev/skills/0xmichalis/agent-rules/sql-indexes"><img src="https://agentmods.dev/badge/skills/0xmichalis/agent-rules/sql-indexes/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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/0xmichalis/agent-rules/sql-indexes"><img src="https://agentmods.dev/badge/skills/0xmichalis/agent-rules/sql-indexes.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 965 The whole file, excluding the scripts and references it only reads on demand.

Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.

Origin unknown No closer match found in the catalogue.

Token cost

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	$0.00063	$0.00965
Opus 5.5	$0.00025	$0.00386
Sonnet 5.5	$0.00013	$0.00193
Haiku 4.5	$0.00006	$0.00097

Measured 2mo ago against content hash 0109475b2f15, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

sql-indexes 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 2mo 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.

.claude/skills/sql-indexes/SKILL.md · 73 lines

The source is not reproduced here

No licence file

Read it on GitHub

Changes

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.

2mo ago Changed · +61 lines 0109475b2f15
2mo ago First seen · 12 lines · 63 tokens per session scan A 575bf881f172

Subscribe to this mod's changes

sql-indexes is a skill published in the GitHub repository 0xmichalis/agent-rules (2 stars, last pushed 2d ago), with no licence file. It adds 63 tokens to every session and 965 once invoked, about $0.0003 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 2026-08-31.

Databases PostgreSQL

sql-indexes next to 6 skills from other repositories
Mod	Type	Stars	Last push	Licence	Scan	Tokens	Works with
sql-indexes0xmichalis/agent-rules	Skill	2	2d ago	none	A	63	Claude Code
alloydb-basicsgoogle/skills	Skill	22k	yesterday	Apache-2.0	A	72	Claude Code, Codex
postgresql-table-designwshobson/agents	Skill	42k	yesterday	MIT	A	37	Claude Code
db-repairgarrytan/gbrain	Skill	32k	yesterday	MIT	A	96	Claude Code
volcengine-rds-postgresqlbytedance/agentkit-samples	Skill	484	today	Apache-2.0	A	63	Claude Code, Codex
dsqlawslabs/agent-plugins	Skill	937	yesterday	Apache-2.0	A	246	Claude Code
analyzing-insights-across-teamsPostHog/posthog-foss	Skill	728	yesterday	MIT	A	115	Claude Code, Codex

agent-rules: Skill for Claude Code