readonly-postgres-mcp
Offers a NestJS module for dependency injection of the readonly PostgreSQL client in NestJS applications.
Provides read-only access to PostgreSQL databases with SQL guardrails for analytical queries and schema introspection.
Click on "Deploy Server".
Wait a few minutes for the server to deploy. Once ready, it will show a "Started" state.
In the chat, type
@followed by the MCP server name and your instructions, e.g., "@readonly-postgres-mcplist all tables in the public schema"
That's it! The server will respond to your query, and you can continue using it as needed.
Here is a step-by-step guide with screenshots.
readonly-postgres-mcp
Readonly PostgreSQL MCP server with SQL guardrails for analytical queries and schema introspection.
This package never writes to the database. There is no write API and no migration runner.
Install from npm
npm install readonly-postgres-mcpOr run the MCP server without a global install:
npx readonly-postgres-mcp pg-readonly-mcpOptional peer for NestJS apps:
npm install @nestjs/commonRelated MCP server: mcp-postgres
Environment
PG_HOST=localhost
PG_PORT=5432
PG_DATABASE=postgres
PG_USERNAME=readonly_user
PG_PASSWORD=...
PG_SSL=false
PG_SEARCH_PATH=public
PG_STATEMENT_TIMEOUT_MS=30000
PG_MAX_ROWS=10000
PG_MCP_ALLOW_ADHOC=trueUse a dedicated database role with SELECT only. See docs/db-role.sql.
Usage
import { PgReadonlyClient, QUERY_IDS } from 'readonly-postgres-mcp';
const pg = await PgReadonlyClient.fromEnv();
const result = await pg.readonly().run(QUERY_IDS.EXAMPLE_PING, {
params: { message: 'hello' },
});
await pg.readonly().query(
'SELECT table_name FROM information_schema.tables WHERE table_schema = $1 LIMIT 10',
{ values: ['public'] },
);
await pg.close();NestJS
import { PgReadonlyModule, NESTJS, PgReadonlyClient } from 'readonly-postgres-mcp/nestjs';
@Module({
imports: [PgReadonlyModule.forRoot()],
})
export class AppModule {}
@Injectable()
export class ReportService {
constructor(@Inject(NESTJS.PG_READONLY_CLIENT) private readonly pg: PgReadonlyClient) {}
}MCP server
Two readonly tools:
Tool | Purpose |
| Named catalog query by |
| Ad-hoc |
pg-readonly-mcpAd-hoc example (pg_query_sql):
{
"sql": "SELECT table_name FROM information_schema.tables WHERE table_schema = 'public' ORDER BY 1 LIMIT 20"
}With positional params:
{
"sql": "SELECT table_name FROM information_schema.tables WHERE table_schema = $1 LIMIT 10",
"values": ["public"]
}Set PG_MCP_ALLOW_ADHOC=false to hide/disable pg_query_sql.
Cursor MCP config:
{
"mcpServers": {
"readonly-postgres-mcp": {
"command": "npx",
"args": ["-y", "readonly-postgres-mcp", "pg-readonly-mcp"],
"env": {
"PG_HOST": "localhost",
"PG_DATABASE": "postgres",
"PG_USERNAME": "readonly_user",
"PG_PASSWORD": "..."
}
}
}
}Adding queries
Add
.sqlunderqueries/using:namedParamsRegister in
registry.jsonRun
npm run validate:catalog
Scripts
npm run validate:catalog
npm test
npm run build
npm run pack:checkPublishing to npm
npm login
npm run pack:check
npm publish --access publicDefense in depth
Layer | Mechanism |
SDK | SqlGuard allowlist + DML scan + param limits + no write API |
Connection |
|
Database | Readonly role with |
This server cannot be deployed
Maintenance
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