write-query

A SQL query writer that turns a plain-language data request into a query for a specified database system. SQL is the language used to retrieve and analyze data stored in tables.

In plain words
What is it for?
Use it to create or optimize queries for systems such as PostgreSQL, Snowflake, BigQuery, Redshift, Databricks, MySQL, SQL Server, DuckDB, or SQLite.
Why use it?
It removes the need to build complex joins, filters, groups, and calculations from scratch, while accounting for differences between database systems.

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/anthropics/knowledge-work-plugins/write-query
Any agent
npx skills add anthropics/knowledge-work-plugins --skill write-query
Clone the repo
git clone --depth 1 https://github.com/anthropics/knowledge-work-plugins

Made for: Claude Code, Codex.

Per session 64 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,082 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 $0.00064 $0.01082
Opus 5 $0.00032 $0.00541
Sonnet 5 $0.00013 $0.00216
Haiku 4.5 $0.00006 $0.00108

Measured 2d ago against content hash 4c7ef791db1f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

write-query 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 2d 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.

Origin

Copies of this mod

2 near-identical copies found in the catalogue:

data/skills/write-query/SKILL.md · 123 lines

How it starts

The opening of the file, as written. The whole thing — 123 lines — stays where its author put it; the contents beside it link to each section on GitHub.

/write-query - Write Optimized SQL

If you see unfamiliar placeholders or need to check which tools are connected, see CONNECTORS.md.

Write a SQL query from a natural language description, optimized for your specific SQL dialect and following best practices.

Usage

/write-query <description of what data you need>

Workflow

1. Understand the Request

Parse the user's description to identify:

  • Output columns: What fields should the result include?
  • Filters: What conditions limit the data (time ranges, segments, statuses)?
  • Aggregations: Are there GROUP BY operations, counts, sums, averages?
  • Joins: Does this require combining multiple tables?
  • Ordering: How should results be sorted?
  • Limits: Is there a top-N or sample requirement?

2. Determine SQL Dialect

If the user's SQL dialect is not already known, ask which they use:

  • PostgreSQL (including Aurora, RDS, Supabase, Neon)
  • Snowflake
  • BigQuery (Google Cloud)
  • Redshift (Amazon)
  • Databricks SQL
  • MySQL (including Aurora MySQL, PlanetScale)
  • SQL Server (Microsoft)
  • DuckDB
  • SQLite
  • Other (ask for specifics)

Remember the dialect for future queries in the same session.

3. Discover Schema (If Warehouse Connected)

If a data warehouse MCP server is connected:

  1. Search for relevant tables based on the user's description
  2. Inspect column names, types, and relationships
  3. Check for partitioning or clustering keys that affect performance
  4. Look for pre-built views or materialized views that might simplify the query

4. Write the Query

Follow these best practices:

Structure:

  • Use CTEs (WITH clauses) for readability when queries have multiple logical steps
  • One CTE per logical transformation or data source
  • Name CTEs descriptively (e.g., daily_signups, active_users, revenue_by_product)

Performance:

  • Never use SELECT * in production queries -- specify only needed columns
  • Filter early (push WHERE clauses as close to the base tables as possible)
  • Use partition filters when available (especially date partitions)
  • Prefer EXISTS over IN for subqueries with large result sets
  • Use appropriate JOIN types (don't use LEFT JOIN when INNER JOIN is correct)
  • Avoid correlated subqueries when a JOIN or window function works
  • Be mindful of exploding joins (many-to-many)

Read the full file on GitHub · 123 lines

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. 2d ago First seen · 123 lines · 64 tokens per session scan A 4c7ef791db1f

Subscribe to this mod's changes

write-query is a skill published in the GitHub repository anthropics/knowledge-work-plugins (23,791 stars, last pushed today), licensed Apache-2.0. It adds 64 tokens to every session and 1,082 once invoked, about $0.0003 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 2026-08-30.

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