awslabs.postgres-mcp-server

An AWS Labs Model Context Protocol (MCP) server for Aurora Postgres

Features

Natural language to Postgres SQL query

• Converting human-readable questions and commands into structured Postgres-compatible SQL queries and executing them against the configured Aurora Postgres database.

Prerequisites

1. Install uv from Astral or the GitHub README
2. Install Python using uv python install 3.10
3. This MCP server can only be run locally on the same host as your LLM client.
4. Docker runtime
5. Set up AWS credentials with access to AWS services
   • You need an AWS account with appropriate permissions
   • Configure AWS credentials with aws configure or environment variables

Installation

Kiro	Cursor	VS Code

Configure the MCP server in your MCP client configuration (e.g., for Kiro, edit ~/.kiro/settings/mcp.json):

{
  "mcpServers": {
    "awslabs.postgres-mcp-server": {
      "command": "uvx",
      "args": [
        "awslabs.postgres-mcp-server@latest",
        "--allow_write_query"
      ],
      "env": {
        "AWS_PROFILE": "your-aws-profile",
        "AWS_REGION": "us-east-1",
        "FASTMCP_LOG_LEVEL": "ERROR"
      },
      "disabled": false,
      "autoApprove": []
    }
  }
}

Windows Installation

For Windows users, the MCP server configuration format is slightly different:

{
  "mcpServers": {
    "awslabs.postgres-mcp-server": {
      "disabled": false,
      "timeout": 60,
      "type": "stdio",
      "command": "uv",
      "args": [
        "tool",
        "run",
        "--from",
        "awslabs.postgres-mcp-server@latest",
        "awslabs.postgres-mcp-server.exe"
      ],
      "env": {
        "FASTMCP_LOG_LEVEL": "ERROR",
        "AWS_PROFILE": "your-aws-profile",
        "AWS_REGION": "us-east-1"
      }
    }
  }
}

Build and install docker image locally on the same host of your LLM client

1. 'git clone https://github.com/awslabs/mcp.git'
2. Go to sub-directory 'src/postgres-mcp-server/'
3. Run 'docker build -t awslabs/postgres-mcp-server:latest .'

Add or update your LLM client's config with following:

Option 1: Using RDS Data API Connection (for Aurora Postgres)

{
  "mcpServers": {
    "awslabs.postgres-mcp-server": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e", "AWS_ACCESS_KEY_ID=[your data]",
        "-e", "AWS_SECRET_ACCESS_KEY=[your data]",
        "-e", "AWS_REGION=[your data]",
        "awslabs/postgres-mcp-server:latest",
        "--allow_write_query"
      ]
    }
  }
}

NOTE: the MCP config example include --allow_write_query illustrate how to enable write queries. If you want to disable write queries, remove --allow_write_query option.

Support for Database Cluster Creation

You can use the following LLM prompt to create a new Aurora PostgreSQL cluster:

Create an Aurora PostgreSQL cluster named 'mycluster' in us-west-2 region

---

Connection Methods

The MCP server supports connecting to multiple database endpoints using different connection methods via LLM prompts.

Database Types

• APG: Amazon Aurora PostgreSQL
• RPG: Amazon RDS for PostgreSQL

Example Prompts

Connect using RDS Data API:

Connect to database named postgres in Aurora PostgreSQL cluster 'my-cluster' with database_type as APG, using rdsapi as connection method in us-west-2 region

Connect using pgwire (Aurora PostgreSQL):

Connect to database named postgres with database endpoint as my-apg17-instance-1.ctgfg6yyo9df.us-west-2.rds.amazonaws.com with database_type as APG, using pgwire as connection method in us-west-2 region

Connect using pgwire (RDS PostgreSQL):

Connect to database named postgres with database endpoint as test-apg17-instance-1.ctgfg6yyo9df.us-west-2.rds.amazonaws.com with database_type as RPG, using pgwire as connection method in us-west-2 region

---

Supported Connection Methods

Method	Description	Supported Database Types
pgwire	Connect to PostgreSQL instance directly using the PostgreSQL wire protocol. Requires proper VPC security group configuration for direct database connectivity.	APG, RPG
pgwire_iam	Same as pgwire, but uses IAM authentication. Requires IAM authentication to be enabled on the Aurora PostgreSQL cluster.	APG only
rdsapi	Connect to Aurora PostgreSQL using the RDS Data API. Requires the RDS Data API to be enabled on the cluster.	APG only

Prerequisites by Connection Method

pgwire / pgwire_iam

• VPC security group must allow inbound connections from your MCP server to the database
• For pgwire_iam: IAM authentication must be enabled on the Aurora PostgreSQL cluster

rdsapi

• RDS Data API must be enabled on the Aurora PostgreSQL cluster
• Appropriate IAM permissions for Data API access

AWS Authentication

The MCP server needs AWS credential to read database cluster or instance data, and to to create clusters or instances. These are control plane operations that are separate from Postgres operations (i.e. SELECT, CREATE etc). If you choose to use rdsapi connection method, the AWS credential must have the rds-data:ExecuteStatement permission on the Aurora cluster (see https://docs.aws.amazon.com/service-authorization/latest/reference/list_amazonrdsdataapi.html). The MCP uses the AWS profile specified in the AWS_PROFILE environment variable. If not provided, it defaults to the "default" profile in your AWS configuration file.

"env": {
  "AWS_PROFILE": "your-aws-profile"
}

Make sure the AWS profile has permissions to access the RDS data API, and the secret from AWS Secrets Manager. The MCP server creates a boto3 session using the specified profile to authenticate with AWS services. Your AWS IAM credentials remain on your local machine and are strictly used for accessing AWS services.

Postgres Authentication

The MCP server supports IAM and username/password methods for Postgres authentication. You must use AWS secret manager to store the credential and to specify the --secretManagerARN in MCP configuration file.

Security Consideration

--allow_write_query read-only enforcement is best effort

When the MCP server runs without --allow_write_query, it rejects queries that appear to mutate data or session state. This is implemented with a keyword and function blocklist (DML/DDL verbs such as INSERT/UPDATE/DROP, session-state statements such as SET/RESET/DISCARD/LOAD, anonymous code blocks DO, and high-impact functions such as pg_terminate_backend, pg_sleep, and the advisory-lock family).

Treat this as a best-effort, defense-in-depth mechanism, not a security boundary. A blocklist cannot enumerate every dangerous construct, and a sufficiently creative query (obfuscation, quoted identifiers, new server/extension functions, etc.) may bypass it. Do not rely on it as your only control.

Best practice: run the MCP server as a minimal-privilege Postgres role

The strongest control is to connect the MCP server using a dedicated Postgres role that has only the privileges it actually needs, so that the database itself enforces the boundary regardless of what SQL reaches it. In particular:

• Do not connect as a superuser, rds_superuser, or the cluster master user. Those roles bypass row-level security, can read credential catalogs (pg_authid, pg_user_mappings), and can terminate other sessions.
• For read-only use, grant only CONNECT + USAGE + SELECT on the schemas the agent needs, and force read-only transactions at the role level.
• For read/write use, grant only the specific INSERT/UPDATE/DELETE privileges required, scoped to the necessary schemas and tables.

Combining a minimal-privilege role (database-enforced) with the blocklist (application-enforced) gives you defense in depth: even if a query slips past the blocklist, the role's privileges still bound what it can do.

The following is an example read-only role:

-- Create a read-only role for Postgres MCP server
CREATE ROLE postgres_mcp_server_readonly WITH LOGIN PASSWORD 'change-me'
    NOSUPERUSER NOCREATEDB NOCREATEROLE NOREPLICATION;

-- Allow connection and schema visibility for public schema
-- TODO: add additional schema if required
GRANT CONNECT ON DATABASE mydb TO postgres_mcp_server_readonly;
GRANT USAGE ON SCHEMA public TO postgres_mcp_server_readonly;

-- Read existing tables and sequences for public schema
-- TODO: add additional schema if required
GRANT SELECT ON ALL TABLES IN SCHEMA public TO postgres_mcp_server_readonly;
GRANT SELECT ON ALL SEQUENCES IN SCHEMA public TO postgres_mcp_server_readonly;

-- Read future tables and sequences for public schema
-- TODO: add additional schema if required
ALTER DEFAULT PRIVILEGES IN SCHEMA public
    GRANT SELECT ON TABLES TO postgres_mcp_server_readonly;
ALTER DEFAULT PRIVILEGES IN SCHEMA public
    GRANT SELECT ON SEQUENCES TO postgres_mcp_server_readonly;

-- Force read-only transactions
ALTER ROLE postgres_mcp_server_readonly SET default_transaction_read_only = on;