database_mcp_postgres/tools/
create_database.rs

1//! MCP tool: `create_database`.
2
3use std::borrow::Cow;
4
5use database_mcp_server::AppError;
6use database_mcp_server::types::{CreateDatabaseRequest, MessageResponse};
7use database_mcp_sql::Connection as _;
8use database_mcp_sql::identifier::validate_identifier;
9use rmcp::handler::server::router::tool::{AsyncTool, ToolBase};
10use rmcp::model::{ErrorData, ToolAnnotations};
11
12use crate::PostgresHandler;
13
14/// Marker type for the `create_database` MCP tool.
15pub(crate) struct CreateDatabaseTool;
16
17impl CreateDatabaseTool {
18    const NAME: &'static str = "create_database";
19    const TITLE: &'static str = "Create Database";
20    const DESCRIPTION: &'static str = r#"Create a new database on the connected server.
21
22<usecase>
23Use when:
24- Setting up a new database for a project or application
25- The user asks to create a database
26</usecase>
27
28<examples>
29✓ "Create a database called analytics" → create_database(database_name="analytics")
30✗ "Create a table" → use write_query with CREATE TABLE
31</examples>
32
33<important>
34Database names must contain only alphanumeric characters and underscores.
35</important>
36
37<what_it_returns>
38A confirmation message with the created database name.
39</what_it_returns>"#;
40}
41
42impl ToolBase for CreateDatabaseTool {
43    type Parameter = CreateDatabaseRequest;
44    type Output = MessageResponse;
45    type Error = ErrorData;
46
47    fn name() -> Cow<'static, str> {
48        Self::NAME.into()
49    }
50
51    fn title() -> Option<String> {
52        Some(Self::TITLE.into())
53    }
54
55    fn description() -> Option<Cow<'static, str>> {
56        Some(Self::DESCRIPTION.into())
57    }
58
59    fn annotations() -> Option<ToolAnnotations> {
60        Some(
61            ToolAnnotations::new()
62                .read_only(false)
63                .destructive(false)
64                .idempotent(false)
65                .open_world(false),
66        )
67    }
68}
69
70impl AsyncTool<PostgresHandler> for CreateDatabaseTool {
71    async fn invoke(handler: &PostgresHandler, params: Self::Parameter) -> Result<Self::Output, Self::Error> {
72        Ok(handler.create_database(&params).await?)
73    }
74}
75
76impl PostgresHandler {
77    /// Creates a database if it doesn't exist.
78    ///
79    /// # Errors
80    ///
81    /// Returns [`AppError`] if read-only or the query fails.
82    pub async fn create_database(&self, request: &CreateDatabaseRequest) -> Result<MessageResponse, AppError> {
83        if self.config.read_only {
84            return Err(AppError::ReadOnlyViolation);
85        }
86        let name = &request.database_name;
87        validate_identifier(name)?;
88
89        // PostgreSQL CREATE DATABASE can't use parameterized queries
90        let create_sql = format!("CREATE DATABASE {}", self.connection.quote_identifier(name));
91        self.connection.execute(&create_sql, None).await.map_err(|e| {
92            let msg = e.to_string();
93            if msg.contains("already exists") {
94                return AppError::Query(format!("Database '{name}' already exists."));
95            }
96            e
97        })?;
98
99        Ok(MessageResponse {
100            message: format!("Database '{name}' created successfully."),
101        })
102    }
103}
database_mcp_postgres/tools/create_database.rs

database_mcp_postgres/tools/
create_database.rs
