rmcp-postgres
A PostgreSQL MCP (Model Context Protocol) server built with [rmcp] https://github.com/modelcontextprotocol/rust-sdk, the Rust MCP SDK.
Provides comprehensive PostgreSQL database access through MCP tools for querying, inserting, updating, deleting, and inspecting database schemas.
Features
- Full CRUD Operations: Query, insert, update, and delete data
- Schema Inspection: List tables, describe schemas, check existence
- Relationship Discovery: Explore foreign key relationships
- Safety Limits: Built-in protections for bulk operations
- Configurable: Flexible database connection configuration
- Library + Binary: Use as a standalone server or integrate into your own Rust projects
Installation
From crates.io
cargo install rmcp-postgres
From source
git clone https://github.com/sqrew/rmcp-postgres
cd rmcp-postgres
cargo build --release
The binary will be at target/release/rmcp-postgres.
Usage
As a Standalone Server
Set your PostgreSQL connection string and run:
# Using environment variable
export POSTGRES_CONNECTION_STRING="host=localhost user=postgres dbname=mydb password=secret"
rmcp-postgres
# Using command line argument
rmcp-postgres --db-config "host=localhost user=postgres dbname=mydb password=secret"
As a Library
Add to your Cargo.toml:
[dependencies]
rmcp-postgres = "0.1"
rmcp = { version = "0.12", features = ["server"] }
tokio = { version = "1", features = ["full"] }
Use in your code:
use rmcp::service::ServiceExt;
use rmcp_postgres::PostgresServer;
#[tokio::main]
async fn main() -> anyhow::Result<()> {
// Create server with connection string
let server = PostgresServer::new("host=localhost user=postgres dbname=mydb");
// Serve over stdio (for MCP)
let (stdin, stdout) = (tokio::io::stdin(), tokio::io::stdout());
server.serve((stdin, stdout)).await?;
Ok(())
}
Claude Desktop Configuration
Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS):
{
"mcpServers": {
"postgres": {
"command": "rmcp-postgres",
"env": {
"POSTGRES_CONNECTION_STRING": "host=localhost user=postgres dbname=mydb password=secret"
}
}
}
}
Or if installed from source:
{
"mcpServers": {
"postgres": {
"command": "/path/to/rmcp-postgres/target/release/rmcp-postgres",
"env": {
"POSTGRES_CONNECTION_STRING": "host=localhost user=postgres dbname=mydb"
}
}
}
}
Available Tools
Data Operations
- query_data - Execute SELECT queries and return JSON results
- insert_data - Insert rows into tables
- update_data - Update rows with WHERE conditions (safety limit: 1000 rows)
- delete_data - Delete rows with WHERE conditions (safety limit: 1000 rows)
- execute_raw_query - Execute any SQL query (use with caution)
Schema Inspection
- list_tables - List all tables in the database
- get_schema - Get column information for tables
- describe_table - Get detailed table info including indexes and constraints
- table_exists - Check if a table exists
- column_exists - Check if a column exists in a table
Utilities
- count_rows - Count rows in a table with optional WHERE conditions
- get_table_sample - Get sample rows from a table (default: 10, max: 100)
- get_relationships - Get foreign key relationships between tables
- get_connection_status - Test connection and get database version info
Connection String Format
PostgreSQL connection strings support multiple formats:
# Basic
"host=localhost user=postgres dbname=mydb"
# With password
"host=localhost user=postgres dbname=mydb password=secret"
# With port
"host=localhost port=5433 user=postgres dbname=mydb"
# Full URL format
"postgresql://postgres:secret@localhost:5432/mydb"
See the tokio-postgres documentation for all connection options.
Examples
Query data
{
"query": "SELECT * FROM users WHERE active = true LIMIT 10"
}
Insert data
{
"table_name": "users",
"data": {
"username": "alice",
"email": "[email protected]",
"active": true
}
}
Update data
{
"table_name": "users",
"values": {
"active": false
},
"where_conditions": {
"username": "alice"
}
}
Get schema for a table
{
"table_name": "users"
}
Safety Features
- Update and delete operations have default limits (1000 rows)
- WHERE conditions required for updates and deletes
- Raw query execution requires explicit tool call
- Connection string passwords are sanitized in logs
Development
# Build
cargo build
# Run tests
cargo test
# Run with debug logging
RUST_LOG=rmcp_postgres=debug,rmcp=debug rmcp-postgres
Contributing
Contributions welcome! Please feel free to submit issues or pull requests.
License
MIT
Related Projects
- rmcp - Rust MCP SDK
- Model Context Protocol - The MCP specification
