Elicitation / Confirmation for Tool Calls

reference

Require user confirmation before the LLM executes specific Couchbase MCP Server tools.

The CB_MCP_CONFIRMATION_REQUIRED_TOOLS environment variable enables user confirmation prompts for tools marked as requiring confirmation. This allows users to double-check the tool call before the LLM executes the actions.

How It Works

When a tool requires confirmation, the server sends an elicitation request to the client.

Clients with elicitation support:

Prompt the user for confirmation.
Send the user’s response back to the server.

Clients without elicitation support: The tool executes without confirmation.

Full functionality requires client support for elicitation.

Configuration

Environment Variable CLI Argument Description Default

Environment Variable	CLI Argument	Description	Default
`CB_MCP_CONFIRMATION_REQUIRED_TOOLS`	`--confirmation-required-tools`	Comma-separated list or file path of tool names that require elicitation/user confirmation before execution	None

CB_MCP_CONFIRMATION_REQUIRED_TOOLS

--confirmation-required-tools

Comma-separated list or file path of tool names that require elicitation/user confirmation before execution

None

Supported Formats

Both settings accept the same two formats.

Comma-Separated List

# Environment variable
CB_MCP_CONFIRMATION_REQUIRED_TOOLS="delete_document_by_id, upsert_document_by_id"

# Command line
uvx couchbase-mcp-server --confirmation-required-tools "delete_document_by_id, upsert_document_by_id"

File Path (One Tool Per Line)

# Environment variable
CB_MCP_CONFIRMATION_REQUIRED_TOOLS=/path/to/confirmation_required_tools.txt

# Command line
uvx couchbase-mcp-server --confirmation-required-tools /path/to/confirmation_required_tools.txt

File format example (confirmation_required_tools.txt):

# Write operations
upsert_document_by_id
delete_document_by_id

# Replace operations
replace_document_by_id

Lines starting with # are treated as comments and ignored.

MCP Client Configuration Examples

Using comma-separated list:

{
  "mcpServers": {
    "couchbase": {
      "command": "uvx",
      "args": ["couchbase-mcp-server"],
      "env": {
        "CB_CONNECTION_STRING": "couchbases://your-connection-string",
        "CB_USERNAME": "username",
        "CB_PASSWORD": "password",
        "CB_MCP_CONFIRMATION_REQUIRED_TOOLS": "upsert_document_by_id,delete_document_by_id"
      }
    }
  }
}

Using file path (recommended for many tools):

{
  "mcpServers": {
    "couchbase": {
      "command": "uvx",
      "args": ["couchbase-mcp-server"],
      "env": {
        "CB_CONNECTION_STRING": "couchbases://your-connection-string",
        "CB_USERNAME": "username",
        "CB_PASSWORD": "password",
        "CB_MCP_CONFIRMATION_REQUIRED_TOOLS": "/path/to/confirmation_required_tools.txt"
      }
    }
  }
}

Important Limitations

Setting CB_MCP_CONFIRMATION_REQUIRED_TOOLS for a tool that did not load has no effect, as the tool is not available. A tool does not load if it’s explicitly listed under the disabled_tools configuration or if READ_ONLY mode is enabled and the tool is not a READ_ONLY tool.

The confirmation_required setting applies explicitly to tools, not to individual actions (such as read, update, or delete operations).

For example, if confirmation_required is enabled for the delete_document_by_id tool, the MCP server prompts for confirmation only when the MCP client selects that specific tool. No confirmation is requested if the client selects a different tool, such as run_sql_plus_plus_query to delete documents.