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 aj-geddes/useful-ai-prompts --skill database-shardinggit clone --depth 1 https://github.com/aj-geddes/useful-ai-promptsWrote 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/aj-geddes/useful-ai-prompts/database-sharding)<a href="https://agentmods.dev/skills/aj-geddes/useful-ai-prompts/database-sharding"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/database-sharding/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/aj-geddes/useful-ai-prompts/database-sharding"><img src="https://agentmods.dev/badge/skills/aj-geddes/useful-ai-prompts/database-sharding.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk 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 | $0.00030 | $0.00556 |
| Opus 5 | $0.00015 | $0.00278 |
| Sonnet 5 | $0.00006 | $0.00111 |
| Haiku 4.5 | $0.00003 | $0.00056 |
Grade A, and why
database-sharding 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 — 89 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Database Sharding
Table of Contents
Overview
Implement horizontal data partitioning across multiple database servers. Covers sharding strategies, consistent hashing, shard key selection, and cross-shard querying patterns.
When to Use
- Database size exceeds single server capacity
- Read/write throughput needs horizontal scaling
- Geographic data distribution requirements
- Multi-tenant data isolation
- Cost optimization through distributed architecture
- Load balancing across database instances
Quick Start
Minimal working example:
-- Define shard ranges
-- Shard 0: user_id 0-999999
-- Shard 1: user_id 1000000-1999999
-- Shard 2: user_id 2000000-2999999
CREATE TABLE users_shard_0 (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
user_id BIGINT NOT NULL,
email VARCHAR(255) NOT NULL,
created_at TIMESTAMP DEFAULT NOW(),
CONSTRAINT shard_0_range CHECK (user_id BETWEEN 0 AND 999999)
);
CREATE TABLE users_shard_1 (
id UUID PRIMARY KEY DEFAULT gen_random_uuid(),
user_id BIGINT NOT NULL,
email VARCHAR(255) NOT NULL,
created_at TIMESTAMP DEFAULT NOW(),
CONSTRAINT shard_1_range CHECK (user_id BETWEEN 1000000 AND 1999999)
);
-- Function to determine shard
CREATE OR REPLACE FUNCTION get_shard_id(p_user_id BIGINT)
RETURNS INT AS $$
BEGIN
// ... (see reference guides for full implementation)
Reference Guides
Detailed implementations in the references/ directory:
| Guide | Contents |
|---|---|
| Range-Based Sharding | Range-Based Sharding |
| Hash-Based Sharding | Hash-Based Sharding |
| Directory-Based Sharding | Directory-Based Sharding |
Best Practices
✅ DO
- Follow established patterns and conventions
- Write clean, maintainable code
- Add appropriate documentation
- Test thoroughly before deploying
What ships with it
5 files 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 · 89 lines · 30 tokens per session scan A c3afd207227f
database-sharding is a skill published in the GitHub repository aj-geddes/useful-ai-prompts (338 stars, last pushed 6mo ago), licensed MIT. It adds 30 tokens to every session and 556 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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