ClickHouse MCP Server vs Redis MCP

ClickHouse MCP Server

Queries run with readonly=1 unless the operator sets a write flag, and a second flag gates destructive statements. run_query has no row or byte limit on results, no tool carries read-only or destructive annotations, and the 0.3.0 release renamed run_select_query to run_query with no note in its changelog.

Redis MCP

Redis's server, under the MIT licence, maps 53 tools onto Redis commands, with typed inputs and a nightly CI run that passed on 9 October 2026. It has no read-only mode, no tool annotations and no changelog file, release 0.5.1 changed the unsubscribe input without a note, and PyPI installs failed to start from 28 July to 5 August 2026.

ClickHouse MCP Server

1. Put a LIMIT on every run_query call. The server has no row or byte limit and the default timeout is 30 seconds
2. Call the tool run_query. ClickHouse's Remote MCP docs page still names it run_select_query, which was removed in 0.3.0
3. Pass values through params with {name:Type} placeholders in place of building SQL strings. Tuple and Map types can't be bound
4. Set include_detailed_columns to false on list_tables for wide schemas. Page tokens are single-use and expire after one hour
5. Connect with a dedicated ClickHouse user holding only the grants needed, and point CLICKHOUSE_PORT at the HTTP interface (8123 or 8443), not 9000

Redis MCP

1. Pass the connection with --url or explicit flags. The redis-mcp-server command overrides REDIS_HOST, REDIS_PORT, REDIS_DB, REDIS_SSL and REDIS_CLUSTER_MODE with its own defaults when flags are absent
2. Use scan_keys with the returned cursor until it is 0. scan_all_keys, hgetall, smembers and json_get return everything they match with no limit
3. Read failures from the text. Tools return strings such as Error ... or an error key in place of an MCP error result
4. Keep the subscription_id from subscribe or psubscribe and pass it to read_messages and unsubscribe. Idle subscriptions close after 300 seconds
5. Connect as a Redis ACL user limited to the keys and command categories needed, since the server has no read-only switch and delete runs without confirmation