claudia-databases

claudia-databases is a skill for Claude Code from reganomalley/claudia. It costs 94 tokens per session (816 once invoked), scanned A, original, MIT.

Database selection and usage guidance covering SQL and NoSQL databases, data modeling, indexing, migrations, scaling, and specialized systems such as vector, graph, and time-series databases. It explains how data shape and access patterns affect the choice.

In plain words
What is it for?
Use it to compare PostgreSQL, MySQL, SQLite, MongoDB, Redis, graph databases, time-series databases, vector databases, and search systems, and to plan database changes.
Why use it?
It helps developers choose a database for their actual data and workload instead of following trends or adding a specialized system too early.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the claudia plugin — 10 skills, 12 commands, 5 hooks shipped together

Good fit Use it to compare PostgreSQL, MySQL, SQLite, MongoDB, Redis, graph databases, time-series databases, vector databases, and search systems, and to plan database changes.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/reganomalley/claudia/claudia-databases
Install

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.

Any agent
npx skills add reganomalley/claudia --skill claudia-databases
Clone the repo
git clone --depth 1 https://github.com/reganomalley/claudia

Made for: Claude Code.

Or install claudia, the plugin that ships this one along with the rest of its 10 skills, 12 commands, 5 hooks.

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.

agentmods badge for claudia-databases

README.md
[![agentmods](https://agentmods.dev/badge/skills/reganomalley/claudia/claudia-databases/github.svg)](https://agentmods.dev/skills/reganomalley/claudia/claudia-databases)
Your own site
<a href="https://agentmods.dev/skills/reganomalley/claudia/claudia-databases"><img src="https://agentmods.dev/badge/skills/reganomalley/claudia/claudia-databases/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.

agentmods 80×15 button for claudia-databases

Your own site · 80×15
<a href="https://agentmods.dev/skills/reganomalley/claudia/claudia-databases"><img src="https://agentmods.dev/badge/skills/reganomalley/claudia/claudia-databases.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 94 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 816 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 original 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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00094 $0.00816
Opus 5 $0.00047 $0.00408
Sonnet 5 $0.00019 $0.00163
Haiku 4.5 $0.00009 $0.00082

Measured 10d ago against content hash 0ff62dbe27fb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

claudia-databases 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 10d 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.

skills/claudia-databases/SKILL.md · 76 lines

How it starts

The opening of the file, as written. The whole thing — 76 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Claudia Database Domain

Overview

This skill helps you choose the right database and use it well. The right answer depends on your data shape, access patterns, scale, and team -- not on what's trending on Hacker News.

The Decision Matrix

Start Here: What Shape Is Your Data?

What does your data look like?
├── Rows and columns, relationships between entities
│   └── Relational (PostgreSQL, MySQL, SQLite)
├── Nested documents, variable schema
│   └── Document (MongoDB, CouchDB)
├── Simple key → value lookups, caching
│   └── Key-Value (Redis, DynamoDB, Memcached)
├── Connections between entities matter most
│   └── Graph (Neo4j, Amazon Neptune)
├── Metrics over time, IoT, monitoring
│   └── Time-Series (TimescaleDB, InfluxDB, QuestDB)
├── AI embeddings, similarity search
│   └── Vector (pgvector, Pinecone, Qdrant, Weaviate)
├── Full-text search, faceted filtering
│   └── Search (Elasticsearch, Meilisearch, Typesense)
└── Not sure / mixed
    └── Start with PostgreSQL (it does most things well enough)

The "Just Use Postgres" Rule

PostgreSQL handles 80% of use cases well. Before reaching for a specialized database, ask:

  • Can Postgres do this with an extension? (pgvector, TimescaleDB, PostGIS, pg_trgm)
  • Is the specialized need actually my bottleneck, or am I optimizing prematurely?
  • Can my team operate another database in production?

Use a specialized DB when: Postgres can technically do it, but you're hitting real performance limits at your actual scale, or the specialized DB's API dramatically simplifies your code.

Quick Comparisons

Need First Choice When to Upgrade
General web app PostgreSQL You probably don't need to
Caching / sessions Redis When you need persistence → Redis with AOF
Document store MongoDB When you need transactions → Postgres JSONB
Embeddings / RAG pgvector >10M vectors or <10ms latency → Pinecone/Qdrant
Time-series TimescaleDB (Postgres ext) >1M inserts/sec → QuestDB or InfluxDB
Graph queries PostgreSQL recursive CTEs >3 hops or complex traversals → Neo4j
Full-text search PostgreSQL ts_vector Complex facets or relevance tuning → Elasticsearch
Prototype / local SQLite Going to production with concurrent writes

Read the full file on GitHub · 76 lines

Files

What ships with it

3 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.

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.

  1. 10d ago First seen · 76 lines · 94 tokens per session scan A 0ff62dbe27fb

Subscribe to this mod's changes

claudia-databases is a skill published in the GitHub repository reganomalley/claudia (4 stars, last pushed 6mo ago), licensed MIT. It adds 94 tokens to every session and 816 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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