ClickHouse Claude Code Plugin extends Claude Code with guidance for ClickHouse schema design, query optimization, and data ingestion, plus a connection to ClickHouse Cloud. It is for developers working with ClickHouse through an AI coding assistant, while its MCP server lets Claude inspect schemas and issue read-only SQL queries against clusters.
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 ClickHouse/clickhouse-claude-code-plugin --skill clickhouse-best-practicesgit clone --depth 1 https://github.com/ClickHouse/clickhouse-claude-code-pluginWrote 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/clickhouse/clickhouse-claude-code-plugin/clickhouse-best-practices)<a href="https://agentmods.dev/skills/clickhouse/clickhouse-claude-code-plugin/clickhouse-best-practices"><img src="https://agentmods.dev/badge/skills/clickhouse/clickhouse-claude-code-plugin/clickhouse-best-practices.svg" alt="Measured on agentmods" height="20"></a>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 | $0.00045 | $0.02532 |
| Opus 5 | $0.00023 | $0.01266 |
| Sonnet 5 | $0.00009 | $0.00506 |
| Haiku 4.5 | $0.00005 | $0.00253 |
Grade A, and why
clickhouse-best-practices 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 8d 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.
This is a copy
100% identical to clickhouse-best-practices — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.
How it starts
The opening of the file, as written. The whole thing — 275 lines — stays where its author put it; the contents beside it link to each section on GitHub.
ClickHouse Best Practices
Comprehensive guidance for ClickHouse covering schema design, query optimization, data ingestion, and AI agent connectivity. Contains 31 rules across 4 main categories (schema, query, insert, agent), prioritized by impact.
Official docs: ClickHouse Best Practices
IMPORTANT: How to Apply This Skill
Before answering ClickHouse questions, follow this priority order:
- Check for applicable rules in the
rules/directory - If rules exist: Apply them and cite them in your response using "Per
rule-name..." - If no rule exists: Use the LLM's ClickHouse knowledge or search documentation
- If uncertain: Use web search for current best practices
- Always cite your source: rule name, "general ClickHouse guidance", or URL
Why rules take priority: ClickHouse has specific behaviors (columnar storage, sparse indexes, merge tree mechanics) where general database intuition can be misleading. The rules encode validated, ClickHouse-specific guidance.
Agent Connectivity & Query Workflow
Before querying ClickHouse, agents must establish a connection and follow the discovery workflow:
rules/agent-connect-mcp.md- Connection setup (MCP + CLI), credential discovery, output format selectionrules/agent-discovery-schema.md- CRITICAL: 7-step schema discovery workflowrules/agent-query-safety.md- CRITICAL: LIMIT, timeouts, progressive exploration
Every agent session should follow this sequence:
- Connect — establish connection via MCP or CLI (see
agent-connect-mcp) - Discover — databases → tables → columns + comments → sort keys → skip indexes → sample → EXPLAIN
- Plan — use sort key and skip index knowledge to write efficient WHERE clauses
- Execute — run queries with LIMIT and timeouts
- Recover — on timeout/memory errors, narrow filters and retry (see
agent-query-safety)
Subagent architecture notes
What ships with it
36 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.
- AGENTS.md 62 KB
- metadata.json 643 B
- README.md 1.9 KB
- rules/_sections.md 1.8 KB
- rules/_template.md 624 B
- rules/agent-connect-mcp.md 4.4 KB
- rules/agent-discovery-schema.md 5.7 KB
- rules/agent-query-safety.md 5.2 KB
- rules/insert-async-small-batches.md 1.8 KB
- rules/insert-batch-size.md 1.5 KB
- rules/insert-format-native.md 933 B
- rules/insert-mutation-avoid-delete.md 2.0 KB
- rules/insert-mutation-avoid-update.md 2.1 KB
- rules/insert-optimize-avoid-final.md 1.9 KB
- rules/query-index-skipping-indices.md 2.4 KB
- rules/query-join-choose-algorithm.md 1.8 KB
- rules/query-join-consider-alternatives.md 2.1 KB
- rules/query-join-filter-before.md 1.3 KB
- rules/query-join-null-handling.md 1.0 KB
- rules/query-join-use-any.md 1.1 KB
- rules/query-mv-incremental.md 2.0 KB
- rules/query-mv-refreshable.md 2.0 KB
- rules/schema-json-when-to-use.md 2.0 KB
- rules/schema-partition-lifecycle.md 1.5 KB
- rules/schema-partition-low-cardinality.md 1.6 KB
- rules/schema-partition-query-tradeoffs.md 1.1 KB
- rules/schema-partition-start-without.md 1.2 KB
- rules/schema-pk-cardinality-order.md 1.6 KB
- rules/schema-pk-filter-on-orderby.md 1.5 KB
- rules/schema-pk-plan-before-creation.md 2.0 KB
- rules/schema-pk-prioritize-filters.md 1.2 KB
- rules/schema-types-avoid-nullable.md 1.8 KB
- rules/schema-types-enum.md 1.7 KB
- rules/schema-types-lowcardinality.md 1.7 KB
- rules/schema-types-minimize-bitwidth.md 1.4 KB
- rules/schema-types-native-types.md 1.8 KB
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.
- 8d ago First seen · 275 lines · 45 tokens per session scan A 00e4c781fd29
clickhouse-best-practices is a skill published in the GitHub repository ClickHouse/clickhouse-claude-code-plugin (6 stars, last pushed 28d ago), licensed Apache-2.0. It adds 45 tokens to every session and 2,532 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to clickhouse-best-practices, differing in 0 lines, and is treated as a copy.
Other skills, from other repositories
schema-exploration
Lists tables, describes columns and data types, identifies foreign key relationships, and maps entity relationships in a database. Use when the user asks about database schema, table structure, column types, what tables exist, ERD, foreign keys, or how entities relate.
ha-data-stores
Map of Hope Agent's local data stores and safe read-only query workflow. Use when the user asks where Hope Agent stores data, wants to inspect sessions/messages/memory/logs/background jobs/knowledge indexes/settings, asks the model to query local app data, or debugging requires checking persisted state. Trigger…
supabase
Supabase / PostgREST Row-Level-Security playbook — pull the anon (or leaked servicerole) key out of the frontend JS, map tables from the auto-generated OpenAPI spec, test anonymous RLS READ disclosures (PII/secret leaks), and anonymous RLS WRITE abuse (insert/update/delete — e.g. forging…
nornicdb-cypher-queries
Pick fast, predictable Cypher query shapes in NornicDB — point lookups, batch retrieval, pagination, search, traversal, batched UNWIND/MERGE writes, cleanup, multi-tenant isolation. Use when writing or reviewing Cypher whose latency or throughput matters; maps user intent to the executor's hot-path query templates.
dsql
Build with Aurora DSQL — manage schemas, execute queries, handle migrations, diagnose query plans, diagnose cluster performance, load data, and develop applications with a serverless, distributed SQL database. Covers IAM auth, multi-tenant patterns, MySQL-to-DSQL and PostgreSQL-to-DSQL schema conversion, foreign key…
volcengine-rds-postgresql
A tool for operating PostgreSQL databases hosted by Volcano Engine's managed database service. PostgreSQL is a relational database used to store structured application data.