Sequel Ace

MySQL/MariaDB database management for macOS

MCP Server (AI Agent Integration)

Sequel Ace includes a built-in Model Context Protocol (MCP) server. It lets AI agents such as Claude Code, Claude Desktop, and Cursor query your databases through Sequel Ace’s existing connections, without any extra tooling or credentials.

The server is disabled by default, listens only on 127.0.0.1, and is never reachable from another machine.

Enabling the server

  1. Open Sequel Ace Preferences (Cmd-,)
  2. Select the MCP Server tab
  3. Check Enable MCP Server (localhost only)
  4. Optionally change the port (default 8765)
  5. Leave Read-only mode enabled (the default) to reject queries that modify data, or uncheck it to allow writes

The preference pane shows a live status line and the server endpoint URL with a Copy button.

Available tools

Tool Description
list_connections List the connections open in Sequel Ace (id, host, current database, which is active)
list_databases List databases on a connection
list_tables List tables and views in a database
describe_table Return columns, indexes, and foreign keys for a table
get_table_ddl Return the CREATE TABLE statement
list_views, list_procedures, list_functions, list_triggers List routines in a database
get_routine_definition Return the CREATE statement for a view/procedure/function/trigger/event
run_query Execute SQL and return results as JSON (capped at 10,000 rows)
explain_query Return the EXPLAIN plan without executing the statement
sample_table Return up to N rows from a table (default 10, max 1000)
count_rows Exact row count of a table
export_results Run a query and write the results to a JSON or CSV file
server_info Server version and key configuration variables
table_sizes Per-table row estimates and storage sizes
process_list SHOW FULL PROCESSLIST
kill_query Terminate a running query/connection by process id (blocked in read-only mode)

Every database tool accepts an optional connection id (from list_connections) to target a specific open tab; it defaults to the active tab. run_query also accepts a params array bound to ? placeholders (injection-safe) and limit/offset for pagination. Table schemas are exposed as MCP resources, reusable prompt templates are provided (analyze schema, summarize table, optimize query), and the server offers argument completion for database, table, and connection names.

Transports

The server speaks two transports on the same port:

  • Streamable HTTP at /mcp - the current MCP transport. Prefer this.
  • HTTP+SSE at /sse - the older transport, kept for clients that do not yet support Streamable HTTP.

Connecting Claude Code

claude mcp add --transport http sequel-ace http://127.0.0.1:8765/mcp

Or add it to your project’s .claude/mcp.json:

{
  "mcpServers": {
    "sequel-ace": {
      "url": "http://127.0.0.1:8765/mcp"
    }
  }
}

Connecting Claude Desktop

Add the following to ~/Library/Application Support/Claude/claude_desktop_config.json, then restart Claude Desktop:

{
  "mcpServers": {
    "sequel-ace": {
      "url": "http://127.0.0.1:8765/mcp"
    }
  }
}

Example prompts

Once connected, you can ask your agent things like:

  • “What tables are in the production database?”
  • “Show me the last 10 orders from the orders table”
  • “Describe the schema of the users table”
  • “Export all products with stock below 10 to a CSV file”

Security notes

  • The server only accepts connections from 127.0.0.1. Connections from any other address receive HTTP 403.
  • Requests that carry a non-loopback Origin header are rejected, so a web page cannot reach the server through your browser (DNS-rebinding protection).
  • Read-only mode is on by default and rejects any statement that is not a SELECT, SHOW, DESCRIBE, or EXPLAIN (it also blocks stacked statements, INTO OUTFILE/DUMPFILE, LOAD_FILE, EXPLAIN ANALYZE, and MySQL/MariaDB executable comments). This is statement-level filtering and cannot detect side effects inside a called stored function or UDF (for example a function that performs an INSERT, or sys_exec). For a hard guarantee, connect with a read-only database user - that boundary is enforced by the server itself.
  • The server exposes whatever databases and privileges the active Sequel Ace connection has.
  • Shared connection / session state. Tools run on the same live connection as the targeted Sequel Ace tab, so per-connection session state is shared in both directions. In read-only mode the statements that change it (USE, SET, BEGIN/START TRANSACTION, LOCK TABLES, CREATE TEMPORARY TABLE) are rejected, but with read-only mode off a tool query could change the tab’s current database, session variables, open transaction, or locks - and even a read clobbers per-connection results like ROW_COUNT(), FOUND_ROWS() and warnings. Keep read-only mode on, and don’t rely on connection-scoped state (user variables, LAST_INSERT_ID(), temporary tables, named locks) being stable across the tab and the agent.
  • Disable the server in Preferences when you are not using it.