mcp-server-db

mcp-server-db is a universal, production-grade Model Context Protocol (MCP) server that empowers AI assistants to interact with Postgres, Redis, Elasticsearch, MySQL, MongoDB, and LDAP through a unified suite of 113+ high-performance tools.

Built with resilience in mind, it features background lazy connection management, exponential backoff retries, circuit breaker patterns, strict read-only security enforcement, and on-demand dynamic driver loading.

Why mcp-server-db?

• Multi-Database Support: Connect to Postgres, Redis, Elasticsearch (v7, v8 & v9), MySQL, MongoDB, and LDAP directories simultaneously.

• On-Demand Light Drivers: Zero bloat. Drivers (pg, ioredis, mongodb, mysql2, @elastic/elasticsearch, ldapts) are dynamically loaded only when a connection to that database engine is initialized.

• Ironclad Safety: Independent per-connection read-only mode with session-level enforcement for relational databases and query result truncation guards to prevent LLM context overflows.

• Fault-Tolerant Architecture: Server starts instantly regardless of database availability. Dead or unreachable databases fail gracefully without crashing the MCP process or blocking other connections.

• Multi-Connection Routing: Query multiple environments (e.g., production read-only replica + local scratch cache) in parallel within the same session.

Related MCP server: Legion Database MCP Server

Supported Database Engines

Quick Start

1. Installation & Optional Drivers

When installed globally (npm install -g mcp-server-db) or run via npx -y mcp-server-db, npm automatically includes all supported database drivers (pg, ioredis, @elastic/elasticsearch, mysql2, mongodb, ldapts) out of the box via optionalDependencies.

# Global installation (includes all drivers out of the box)
npm install -g mcp-server-db

# Local project installation
npm install mcp-server-db

If you install mcp-server-db locally using --no-optional to keep your node_modules lightweight, you can install only the specific drivers you need:

# PostgreSQL
npm install pg

# Redis
npm install ioredis

# Elasticsearch
npm install @elastic/elasticsearch   # For v8 & v9
npm install es7-client               # For v7 legacy

# MySQL / MariaDB
npm install mysql2

# MongoDB
npm install mongodb

# LDAP
npm install ldapts

2. Zero-Install Execution via NPX

Add mcp-server-db directly to your MCP client config file (e.g. Claude Desktop, Claude Code, Gemini CLI, Cursor):

{
  "mcpServers": {
    "mcp-server-db": {
      "type": "stdio",
      "command": "npx",
      "args": ["-y", "mcp-server-db"],
      "env": {
        "POSTGRES_URL": "postgresql://user:password@localhost:5432/mydb",
        "REDIS_URL": "redis://localhost:6379",
        "MONGODB_URL": "mongodb://localhost:27017",
        "LDAP_URL": "ldap://localhost:389",
        "LDAP_BIND_DN": "cn=admin,dc=example,dc=com",
        "LDAP_BIND_PASSWORD": "admin-password"
      }
    }
  }
}

3. Fast Setup with Environment Variables

Define connection strings in env to start immediately without a configuration file:

POSTGRES_URL=postgresql://user:password@localhost:5432/mydb
REDIS_URL=redis://localhost:6379
ELASTICSEARCH_URL=http://localhost:9200
MYSQL_URL=mysql://user:password@localhost:3306/mydb
MONGODB_URL=mongodb://localhost:27017
LDAP_URL=ldap://localhost:389
LDAP_BIND_DN=cn=admin,dc=example,dc=com
LDAP_BIND_PASSWORD=admin-password
POSTGRES_READ_ONLY=true
REDIS_READ_ONLY=true
MYSQL_READ_ONLY=true
MONGODB_READ_ONLY=true
LDAP_READ_ONLY=true

Complete Tools Reference (113 Tools)

System & Management Tools (2)

• db_status: Inspect connection states (idle, connecting, connected, retrying, failed, circuit_open), read-only mode, and error logs across all configured databases.

• db_reload_config: Hot-reload databases.config.yml from disk and reconcile connections dynamically without interrupting active queries.

Postgres Tools (30)

• pg_query: Execute read-only SELECT queries (enforces single-statement extended query protocol).

• pg_execute_sql: Execute write SQL statements (INSERT, UPDATE, DELETE, DDL). Blocked in read-only mode.

• pg_list_tables: List tables in a target schema.

• pg_describe_table: Inspect column data types, ordinal position, and nullability.

• pg_list_schemas: List all database schemas.

• pg_list_views: List all views in a schema.

• pg_list_indexes: List indexes and index definitions for a table.

• pg_list_triggers: List triggers and action statements in a schema.

• pg_table_stats: Get total size, table size, index size, and estimated row count.

• pg_list_constraints: List primary keys, foreign keys, and check constraints.

• pg_explain_query: Inspect query execution plans with EXPLAIN.

• pg_active_queries: Retrieve running non-idle queries and durations from pg_stat_activity.

• pg_list_functions: List user-defined functions, arguments, and return types.

• pg_list_sequences: List sequence objects in a schema.

• pg_database_info: Get database name, current user, PostgreSQL version, and database size.

• pg_kill_query: Terminate a running backend process by PID. Blocked in read-only mode.

• pg_vacuum_analyze: Run VACUUM ANALYZE to update statistics and reclaim dead tuples. Blocked in read-only mode.

• pg_list_materialized_views: List materialized views in a schema.

• pg_refresh_materialized_view: Refresh a materialized view (supports CONCURRENTLY). Blocked in read-only mode.

• pg_index_usage: Inspect index scan counts and tuple fetch statistics.

• pg_lock_info: Retrieve active database locks and query durations.

• pg_get_top_queries: Get slow queries from pg_stat_statements.

• pg_explain_hypothetical_index: Simulate hypothetical index performance using hypopg.

• pg_database_health: Run health audit (connections utilization, buffer cache hit ratio, dead rows, replication lag).

• pg_sizes_overview: Breakdown storage sizes for database, tables, and indexes.

• pg_unused_indexes: Identify zero-scan candidate indexes to drop.

• pg_duplicate_indexes: Find overlapping or redundant indexes.

• pg_long_running_queries: Find queries exceeding a duration threshold.

• pg_missing_indexes: Identify high-sequential-scan tables needing indexes.

• pg_bloat_estimate: Estimate table bloat ratio based on dead tuple count.

Redis Tools (27)

• redis_get: Get string value at key.

• redis_set: Set key value. Blocked in read-only mode.

• redis_mset: Set multiple key/value pairs in a single command (e.g. for seeding). Blocked in read-only mode.

• redis_del: Delete key. Blocked in read-only mode.

• redis_keys: List keys matching a glob pattern (capped at 1000 items).

• redis_ttl: Get remaining TTL in seconds.

• redis_hget: Get hash field value.

• redis_hset: Set hash field value. Blocked in read-only mode.

• redis_hdel: Delete hash fields. Blocked in read-only mode.

• redis_hgetall: Get all hash fields and values.

• redis_hexists: Check hash field existence.

• redis_sadd: Add member to set. Blocked in read-only mode.

• redis_srem: Remove member from set. Blocked in read-only mode.

• redis_smembers: List set members (capped at 1000 items).

• redis_sismember: Test set membership.

• redis_lpush: Prepend element to list. Blocked in read-only mode.

• redis_rpush: Append element to list. Blocked in read-only mode.

• redis_lpop: Remove and return first list element. Blocked in read-only mode.

• redis_rpop: Remove and return last list element. Blocked in read-only mode.

• redis_lrange: Get range of list elements (capped at 1000 items).

• redis_llen: Get list length.

• redis_exists: Check key existence.

• redis_expire: Set key expiration in seconds. Blocked in read-only mode.

• redis_type: Retrieve data type of key.

• redis_incr: Increment integer key. Blocked in read-only mode.

• redis_decr: Decrement integer key. Blocked in read-only mode.

• redis_flushdb: Clear current Redis database. Blocked in read-only mode.

Elasticsearch Tools (11)

• es_cluster_health: Get status (green/yellow/red), node counts, and shard metrics.

• es_list_indices: List indices, doc counts, store size, and status.

• es_index_stats: Get detailed metrics for a specific index.

• es_search: Execute search using Query DSL.

• es_count: Count documents matching a query.

• es_get_doc: Fetch document by ID.

• es_index_doc: Index or overwrite document. Blocked in read-only mode.

• es_bulk_index: Index multiple documents into one index in a single _bulk request, with per-document success/failure reporting (e.g. for seeding). Blocked in read-only mode.

• es_update_doc: Partially update document fields. Blocked in read-only mode.

• es_delete_doc: Delete document by ID. Blocked in read-only mode.

• es_delete_by_query: Delete documents matching Query DSL. Blocked in read-only mode.

MySQL Tools (18)

• mysql_query: Execute read-only SELECT/SHOW/EXPLAIN queries.

• mysql_execute_sql: Execute write SQL (INSERT, UPDATE, DELETE, DDL). Blocked in read-only mode.

• mysql_list_databases: List databases on server.

• mysql_list_tables: List tables in database.

• mysql_list_views: List views and security options.

• mysql_describe_table: Show column definitions and metadata.

• mysql_show_create_table: Extract raw CREATE TABLE DDL statement.

• mysql_show_create_view: Extract raw CREATE VIEW DDL statement.

• mysql_list_indexes: Show table indexes (SHOW INDEX).

• mysql_list_triggers: List database triggers.

• mysql_list_routines: List stored procedures and functions.

• mysql_list_constraints: List foreign keys and constraints.

• mysql_table_stats: Retrieve estimated rows, data length, and index size.

• mysql_active_queries: Retrieve running threads (SHOW FULL PROCESSLIST).

• mysql_kill_query: Kill running process by ID. Blocked in read-only mode.

• mysql_explain_query: Analyze query execution plan (EXPLAIN).

• mysql_global_status: Query server global status metrics.

• mysql_analyze_table: Run ANALYZE TABLE to refresh statistics. Blocked in read-only mode.

MongoDB Tools (19)

• mongo_list_databases: List databases on MongoDB cluster.

• mongo_list_collections: List collections in database.

• mongo_find: Query documents with filter, projection, sort, limit, and skip.

• mongo_distinct: Get unique field values.

• mongo_aggregate: Execute MongoDB aggregation pipeline.

• mongo_count_documents: Count documents matching filter.

• mongo_insert_one: Insert single document. Blocked in read-only mode.

• mongo_insert_many: Insert array of documents. Blocked in read-only mode.

• mongo_update_one: Update single document matching filter. Blocked in read-only mode.

• mongo_update_many: Update multiple documents. Blocked in read-only mode.

• mongo_delete_one: Delete single document. Blocked in read-only mode.

• mongo_delete_many: Delete multiple documents. Blocked in read-only mode.

• mongo_create_index: Create collection index. Blocked in read-only mode.

• mongo_drop_index: Drop collection index by name. Blocked in read-only mode.

• mongo_list_indexes: List all collection indexes.

• mongo_db_stats: Get database storage statistics.

• mongo_collection_stats: Get storage, index size, and object count for collection.

• mongo_explain: Get query planner execution plan and index scan metrics.

• mongo_server_status: Get cluster memory, connection, and operation stats.

LDAP Tools (6)

• ldap_search: Search a directory by base DN, filter, and scope (capped at 500 entries).

• ldap_compare: Compare an attribute/value pair against an entry.

• ldap_add: Create a new entry. Blocked in read-only mode.

• ldap_add_bulk: Create multiple entries in one call (e.g. for seeding), with per-entry success/failure reporting. Blocked in read-only mode.

• ldap_modify: Add, replace, or delete an attribute's values on an entry. Blocked in read-only mode.

• ldap_delete: Delete an entry. Blocked in read-only mode.

Multi-Connection YAML Configuration

For complex setups with multiple named databases, create config/databases.config.yml (copy config/databases.config.example.yml):

connections:
  - id: primary-pg
    type: postgres
    connectionString: ${POSTGRES_URL}
    defaultSchema: public
    statementTimeoutMs: 30000
    readOnly: true

  - id: app-cache
    type: redis
    connectionString: ${REDIS_URL}
    readOnly: false

  - id: search-logs
    type: elasticsearch
    connectionString: ${ELASTICSEARCH_URL}
    apiVersion: "9"
    readOnly: true

  - id: legacy-cluster
    type: elasticsearch
    connectionString: ${LEGACY_ELASTICSEARCH_URL}
    apiVersion: "7"
    readOnly: true

  - id: analytics-mysql
    type: mysql
    connectionString: ${MYSQL_URL}
    statementTimeoutMs: 30000
    readOnly: true

  - id: document-store
    type: mongodb
    connectionString: ${MONGODB_URL}
    defaultDatabase: production
    readOnly: true

  - id: directory
    type: ldap
    connectionString: ${LDAP_URL}
    bindDn: ${LDAP_BIND_DN}
    bindPassword: ${LDAP_BIND_PASSWORD}
    readOnly: false

Local Development & Custom Builds

1. Build and Run Locally

git clone https://github.com/Nam088/mcp-database-server-v2.git
cd mcp-database-server
npm install
npm run build    # Compiles TypeScript to dist/
npm test         # Runs Vitest test suite

2. Configure Local Build in MCP Clients

{
  "mcpServers": {
    "mcp-server-db": {
      "type": "stdio",
      "command": "node",
      "args": ["/absolute/path/to/mcp-database-server/dist/index.js"],
      "env": {
        "DATABASES_CONFIG_PATH": "/absolute/path/to/mcp-database-server/config/databases.config.yml"
      }
    }
  }
}

3. Claude Code CLI

claude mcp add --scope user mcp-server-db node /absolute/path/to/mcp-database-server/dist/index.js --env DATABASES_CONFIG_PATH=/absolute/path/to/mcp-database-server/config/databases.config.yml

Client Config Paths

• Claude Desktop: ~/Library/Application Support/Claude/claude_desktop_config.json

• Claude Code (Global): ~/.claude.json

• Gemini CLI / IDE: ~/.gemini/config/mcp_config.json

• Cursor / Project Root: .mcp.json

License

Distributed under the MIT License. See LICENSE for details.