PostgreSQL (archived MCP reference server) vs Redis MCP

PostgreSQL (archived MCP reference server)

The server exposes one small query tool. Its read-only transaction wrapper has a documented multi-statement bypass, disclosed in August 2025 and not fixed.

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.

PostgreSQL (archived MCP reference server)

1. Don't use for new work. Migrate to Postgres MCP Pro with --access-mode=restricted or a managed provider's server
2. If you inherit it, connect with a database role that can only SELECT. The transaction won't stop writes
3. Add LIMIT to every query. The server returns every row as pretty-printed JSON
4. Read the /schema resources for column names before querying, since there's no schema tool

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