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PostgreSQL MCP Server for Claude Desktop

by User-Gold

🐘 PostgreSQL MCP Server for Claude Desktop

Connect Claude Desktop to your PostgreSQL database using the Model Context Protocol (MCP). Ask Claude questions in plain English and it will query your database, explore schemas, and analyze data β€” no SQL required.


✨ Features

Category

Tools

πŸ—„οΈ Database Info

get_database_info, list_databases

πŸ“‚ Schema Exploration

list_schemas, list_tables, describe_table, search_schema, list_indexes

πŸ” Querying

execute_query, get_table_sample, get_table_stats, explain_query

✏️ Write Operations

execute_write (disabled by default β€” opt-in via .env)

πŸ“„ Resources

schema://overview, table://{schema}/{table}

πŸ’¬ Prompts

analyze_table, write_sql_query


πŸš€ Quick Start

1. Clone the Repository

git clone https://github.com/sarotechhub/Claude-Desktop-to-PostgreSQL.git cd Cluade-MCP-PostgreSQL

2. Create a Virtual Environment

# Windows python -m venv .venv .venv\Scripts\activate # macOS / Linux python -m venv .venv source .venv/bin/activate

3. Install Dependencies

pip install -r requirements.txt

4. Configure Your Database

# Copy the example env file cp .env.example .env

Edit .env with your PostgreSQL credentials:

DB_HOST=localhost DB_PORT=5432 DB_NAME=your_database_name DB_USER=your_username DB_PASSWORD=your_password # Set to "true" to allow INSERT/UPDATE/DELETE ALLOW_WRITE_OPERATIONS=false

All credentials live only in β€” they are never put in the Claude Desktop config file.

5. Test the Server

python main.py

You should see:

πŸš€ Starting PostgreSQL MCP Server... βœ… Database connection pool ready.

Press Ctrl+C to stop.

6. Connect to Claude Desktop

Find your Claude Desktop config file:

OS

Path

Windows

%APPDATA%\Claude\claude_desktop_config.json

macOS

~/Library/Application Support/Claude/claude_desktop_config.json

Linux

~/.config/Claude/claude_desktop_config.json

Add the to the mcpServers section (update the path):

{ "mcpServers": { "postgres": { "command": "[PATH_TO_YOUR_VENV_PYTHON_EXE]", "args": ["[PATH_TO_YOUR_PROJECT_ROOT]\\main.py"], "cwd": "[PATH_TO_YOUR_PROJECT_ROOT]", "env": { "PYTHONPATH": "[PATH_TO_YOUR_PROJECT_ROOT]" } } } }

Note: No DB credentials go in this file. The server reads them automatically from your .env file using python-dotenv.

Restart Claude Desktop after saving the config.


πŸ’¬ Example Conversations with Claude

Once connected, try asking Claude:

"List all tables in my database" "Describe the structure of the users table" "Show me 10 sample rows from the orders table" "How many rows are in each table in the public schema?" "Find all columns related to 'email' across all tables" "What indexes exist on the products table?" "Write a query to find the top 10 customers by total order value" "Explain why this query might be slow: SELECT * FROM orders WHERE status = 'pending'"

πŸ”§ Tool Reference

Database Info

Tool

Description

get_database_info

PostgreSQL version, DB size, connection count, server info

list_databases

All databases on the server with sizes and encoding

Schema Exploration

Tool

Description

list_schemas()

All user-defined schemas in the connected database

list_tables(schema)

Tables in a schema with row counts and sizes

describe_table(table, schema)

Columns, types, nullable, defaults, PKs, FKs

search_schema(keyword)

Find tables/columns by keyword (case-insensitive)

list_indexes(table, schema)

Indexes on a table with type and columns

Querying

Tool

Description

execute_query(sql, limit)

Read-only SELECT (enforced via read-only transaction)

get_table_sample(table, schema, limit)

Sample rows from a table (max 100)

get_table_stats(table, schema)

Row counts, sizes, vacuum/analyze timestamps

explain_query(sql)

EXPLAIN execution plan (no data modification)

Write Operations

Tool

Description

execute_write(sql, confirm)

INSERT/UPDATE/DELETE β€” requires ALLOW_WRITE_OPERATIONS=true in .env AND confirm=True


πŸ”’ Security

  • Read-only by default β€” write operations require explicit opt-in in .env

  • Credentials in β€” never in the Claude Desktop config

  • Read-only transactions β€” SELECT queries run inside readonly=True transactions

  • Input validation β€” table/schema names validated with regex to prevent injection

  • No DDL β€” DROP, CREATE, ALTER are always blocked even when writes are enabled

  • .env β€” credentials never committed


πŸ“ Project Structure

Cluade-MCP-PostgreSQL/ β”œβ”€β”€ main.py # πŸš€ MCP server entry point (FastMCP + stdio) β”œβ”€β”€ database.py # πŸ”Œ Async connection pool (asyncpg) β”œβ”€β”€ tools/ β”‚ β”œβ”€β”€ __init__.py β”‚ β”œβ”€β”€ schema_tools.py # list_schemas, list_tables, describe_table, search_schema, list_indexes β”‚ β”œβ”€β”€ query_tools.py # execute_query, get_table_sample, get_table_stats, explain_query β”‚ β”œβ”€β”€ write_tools.py # execute_write (opt-in) β”‚ └── database_tools.py # get_database_info, list_databases β”œβ”€β”€ .env # βœ… Your credentials (NOT committed to git) β”œβ”€β”€ .env.example # Template for new users β”œβ”€β”€ .gitignore # Excludes .env, .venv, __pycache__ β”œβ”€β”€ requirements.txt # mcp[cli], asyncpg, python-dotenv, pydantic, orjson β”œβ”€β”€ claude_desktop_config.json # Example Claude Desktop config snippet └── README.md

βš™οΈ Environment Variables

All configuration is done via .env:

Variable

Default

Description

DB_HOST

localhost

PostgreSQL host

DB_PORT

5432

PostgreSQL port

DB_NAME

β€”

Database name

DB_USER

β€”

Database user

DB_PASSWORD

β€”

Database password

DB_MIN_CONNECTIONS

1

Min pool connections

DB_MAX_CONNECTIONS

10

Max pool connections

ALLOW_WRITE_OPERATIONS

false

Enable INSERT/UPDATE/DELETE

LOG_LEVEL

INFO

Logging level (DEBUG/INFO/WARNING)


πŸ› οΈ Troubleshooting

Claude doesn't see the MCP server

  • Fully quit and reopen Claude Desktop after editing the config

  • Check the cwd path β€” it must point to the project folder

  • Verify the .venv Python path is correct: .venv\Scripts\python.exe

Connection refused / authentication failed

  • Check your .env credentials match your PostgreSQL setup

  • Test directly: psql -h localhost -U your_user -d your_db

  • Ensure PostgreSQL is running: pg_isready

mcp or asyncpg module not found

.venv\Scripts\pip install -r requirements.txt

Server starts but tools don't appear in Claude

  • Open Claude Desktop β†’ Settings β†’ Developer β†’ MCP Servers

  • Check for error messages next to the postgres server entry

  • Run python main.py manually and check stderr for import errors


πŸ“‹ Requirements

  • Python 3.10+

  • PostgreSQL 12+

  • Claude Desktop (with MCP support)


πŸ“„ License

MIT License β€” free to use, modify, and distribute.


🀝 Contributing

Pull requests welcome! Please fork the repo, create a feature branch, and submit a PR with a clear description.

Claude-Desktop-to-PostgreSQL

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security - not tested
F
license - not found
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quality - not tested

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