4 tools. 2 can modify or destroy data without limits.
2 write tools that can modify data. Rate limits recommended.
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Execute tools (run_chdb_select_query, run_query) trigger processes with side effects. Builds, notifications, workflows — all fired without throttling.
Intercept sits between your agent and ClickHouse. Every tool call checked against your policy before it executes — so your agent can do its job without breaking things.
npx -y @policylayer/intercept scan -- npx -y @ClickHouse/mcp-clickhouse list_databases:
rules:
- rate_limit: 60/minute Controls API costs and prevents retry loops from exhausting upstream rate limits.
The ClickHouse server is primarily read-only with 2 read tools. While it cannot modify data, an agent in a retry loop can make thousands of API calls per minute, exhausting rate limits and running up costs. Rate limiting is still recommended.
4 tools across 2 categories: Execute, Read. 2 are read-only. 2 can modify, create, or delete data.
One line change. Instead of running the ClickHouse server directly, prefix it with Intercept: intercept -c clickhouse.yaml -- npx -y @@ClickHouse/mcp-clickhouse. Download a pre-built policy from policylayer.com/policies/clickhouse and adjust the limits to match your use case.
Starter policies available for each. Same risk classification, same one-command setup.
Set budgets, approvals, and hard limits across MCP servers.
npx -y @policylayer/intercept init