database

A procedure for investigating slow database queries and the code that builds them. It examines the database’s execution plan, checks for repeated queries inside loops, and proposes query and index changes.

In plain words
What is it for?
Use it to analyze SQL or ORM code, inspect filtering, joining, and sorting, replace repeated queries with batching or joins, and produce index definitions.
Why use it?
It helps find full-table scans, missing indexes, and N+1 query patterns, where one page operation causes an extra query for every item. These problems can create unnecessary disk work and slow down pages.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/v0idos/performance-deity/database
Any agent
npx skills add v0idOS/performance-deity --skill database
Clone the repo
git clone --depth 1 https://github.com/v0idOS/performance-deity

Made for: Claude Code, Codex.

Per session 34 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 308 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00034 $0.00308
Opus 5 $0.00017 $0.00154
Sonnet 5 $0.00007 $0.00062
Haiku 4.5 $0.00003 $0.00031

Measured yesterday against content hash 252f2245b25e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

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 yesterday.

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/database/SKILL.md · 36 lines

What it actually says

Execute all three phases in order.

Phase 1 — Analysis

  1. Take the slow query or ORM code.
  2. Generate the equivalent raw SQL.
  3. Either instruct the user to run EXPLAIN QUERY PLAN (SQLite) or EXPLAIN ANALYZE (Postgres/MySQL), or infer missing indexes directly from the WHERE, JOIN, and ORDER BY clauses.

Phase 2 — N+1 Audit

Check whether queries are issued inside a loop. If yes, rewrite using:

  • IN (...) batch clause
  • SQL JOIN
  • ORM eager loading:
    • .include() — Prisma
    • .populate() — Mongoose
    • select_related() / prefetch_related() — Django

Phase 3 — Rewrite

  1. Provide the optimized SQL or ORM code.
  2. Provide the exact CREATE INDEX statements required.
  3. Explain the disk I/O reduction: Full Table Scan O(N) → Index Lookup O(log N).

Before/after query plan summary:

Metric Before After
Scan type Full Table Scan Index Lookup
Complexity O(N) O(log N)
Query count (per page load) N+1 1
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. yesterday First seen · 36 lines · 34 tokens per session scan A 252f2245b25e

Subscribe to this mod's changes

database is a skill published in the GitHub repository v0idOS/performance-deity (2 stars, last pushed 4mo ago), licensed MIT. It adds 34 tokens to every session and 308 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 2026-08-31.

Related

Other skills, from other repositories

agent-evaluation-reporting

Use when summarizing agent evaluations where autonomous, assisted, failed, timed-out, or invalid outcomes must remain distinct and comparable.

sickn33/agentic-awesome-skills · 31 tokens

nemo-evaluator-sdk

Evaluates LLMs across 100+ benchmarks from 18+ harnesses (MMLU, HumanEval, GSM8K, safety, VLM) with multi-backend execution. Use when needing scalable evaluation on local Docker, Slurm HPC, or cloud platforms. NVIDIA's enterprise-grade platform with container-first architecture for reproducible benchmarking.

Orchestra-Research/AI-Research-SKILLs · 76 tokens

evaluating-code-models

Evaluates code generation models across HumanEval, MBPP, MultiPL-E, and 15+ benchmarks with pass@k metrics. Use when benchmarking code models, comparing coding abilities, testing multi-language support, or measuring code generation quality. Industry standard from BigCode Project used by HuggingFace leaderboards.

Orchestra-Research/AI-Research-SKILLs · 68 tokens

evaluating-llms-harness

Evaluates LLMs across 60+ academic benchmarks (MMLU, HumanEval, GSM8K, TruthfulQA, HellaSwag). Use when benchmarking model quality, comparing models, reporting academic results, or tracking training progress. Industry standard used by EleutherAI, HuggingFace, and major labs. Supports HuggingFace, vLLM, APIs.

Orchestra-Research/AI-Research-SKILLs · 85 tokens

Gene Panel Selection Workflow

End-to-end workflow for gene panel design in scRNA-seq and spatial transcriptomics, that should be STRICTLY followed: dataset understanding + smart downsampling + train/test splits, algorithmic selection (HVG/DE/RF/scGeneFit/SpaPROS), optimal sub-panel discovery (ARI vs size), biological completion with a stability…

aristoteleo/PantheonOS · 110 tokens

benchmark-radar

Find, inspect, and check AI benchmark records with the Benchmark Radar CLI. Use when a request needs benchmark discovery, details, recent Radar evidence, or local data health; do not assume why the user needs the results.

ktwu01/benchmark-radar · 48 tokens