Enable or Disable MongoDB MCP Server Features

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Enable or Disable MongoDB MCP Server Features

The MongoDB MCP Server has various options that you can enable or disable. For example: read-only mode, specific MCP tools, telemetry about system use, and database index checks.

Enabling MCP Server Read-Only Mode

You can limit the MCP Server to perform only read operations using read-only mode.

Default is to allow cluster write operations. Typically, always enable read-only mode.

To enable read-only mode with a command line option, use:

--readOnly

To enable read-only mode using an environment variable, set the MDB_MCP_READ_ONLY environment variable to true:

export MDB_MCP_READ_ONLY=true

When you enable read-only mode, a message is added to the MCP Server log that indicates the tools that perform write operations are prevented from running.

Disabling MCP Server Tools

To restrict access to Atlas and database operations, you can disable specific MCP Server tools or categories of tools.

To disable tools, set the disabledTools MCP Server configuration option, which is an array of strings. Each string can be a tool name or tool category.

The following table shows the tool names that you can disable:

Tool Name Description Example Operations Disabled
create Create resources Create cluster; Insert document
update Update resources Update document; Rename collection; Pause or resume cluster
delete Delete resources Delete document; Drop collection
read Read resources Find; Aggregate; List clusters
metadata Read metadata List databases; List collections; Read collection schema

The following table shows the tool categories that you can disable:

Tool Category Description Example Operations Disabled
atlas Atlas tools List clusters; Create cluster
mongodb Database tools Find; Aggregate

To disable tools with the disabledTools command line option, use a comma-separated list. For example:

--disabledTools create,update,delete,atlas

To disable tools with the MDB_MCP_DISABLED_TOOLS environment variable, use a comma-separated string. For example:

export MDB_MCP_DISABLED_TOOLS="create,update,delete,atlas"

Disabling MCP Server Telemetry

To prevent the MCP Server from collecting data about usage, you can disable telemetry.

To disable telemetry using an environment variable, set either of these:

export MDB_MCP_TELEMETRY=disabled
export DO_NOT_TRACK=1

To disable telemetry using a command line option, use:

--telemetry disabled

Enabling Index Check

To ensure query operations use an index, enable the index check option. When enabled, the MCP Server rejects queries that perform a collection scan to improve performance and ensure queries are optimized.

To enable the index check with a command line option, use:

--indexCheck

To enable the index check with an environment variable, use:

export MDB_MCP_INDEX_CHECK=true

If you enable the index check, the MCP Server logs an error message if a query is rejected because it doesn't use an index.

Enabling Server-Side JavaScript Functions

The MCP Server disables server-side JavaScript functions ($where, $function, and $accumulator) by default to prevent unintended behavior. These functions are deprecated in MongoDB 8.0 and later. To learn more, see Server-Side JavaScript.

To enable server-side JavaScript functions with a command line option, use:

--disableServerSideJs false

To enable server-side JavaScript functions using an environment variable, set the MDB_MCP_DISABLE_SERVER_SIDE_JS environment variable to false:

export MDB_MCP_DISABLE_SERVER_SIDE_JS=false

Enabling MCP Server Dry-Run Mode

Use the dry-run option to examine your MCP Server configuration. When you enable the dry-run option, the MCP Server returns the MCP Server configuration settings and the list of enabled [MongoDB MCP Server Tools.](https://www.mongodb.com/docs/mcp-server/tools.md#std-label-mcp-server-tools

To enable dry-run mode with a command line option, use:

--dryRun

To enable dry-run mode using an environment variable, set the MDB_MCP_DRY_RUN environment variable to true:

export MDB_MCP_DRY_RUN=true

The MCP Server returns the configuration and enabled tools in the command line output.

Learn More

  • [MongoDB MCP Server Configuration Options](https://www.mongodb.com/docs/mcp-server/local-mcp/configuration/options.md#std-label-mcp-server-configuration-options

  • [MongoDB MCP Server Configuration Methods](https://www.mongodb.com/docs/mcp-server/local-mcp/configuration/methods.md#std-label-mcp-server-configuration-methods

  • [Export Data from MongoDB MCP Server](https://www.mongodb.com/docs/mcp-server/local-mcp/configuration/export-data.md#std-label-mcp-server-configuration-export-data

  • [Start MongoDB MCP Server as a Standalone Service](https://www.mongodb.com/docs/mcp-server/local-mcp/configuration/standalone-service.md#std-label-mcp-server-configuration-standalone-service

  • [MongoDB MCP Server Memory Overflow](https://www.mongodb.com/docs/mcp-server/local-mcp/configuration/memory-overflow.md#std-label-mcp-server-configuration-memory-overflow

  • [Troubleshoot the Local MCP Server](https://www.mongodb.com/docs/mcp-server/local-mcp/configuration/troubleshooting.md#std-label-mcp-server-configuration-troubleshooting