@adriancy/mcp-mssql

MCP server (stdio) for Microsoft SQL Server. Exposes tools so Cursor (or any MCP client) can list tables, describe columns, and run read-biased T-SQL.

Use it in Cursor

1. Open Cursor Settings → MCP (or edit your MCP JSON).
2. Add a server block. Set env to your database (see .env.example).

From npm (after the package is published):

{
  "mcpServers": {
    "mssql": {
      "command": "npx",
      "args": ["-y", "@adriancy/mcp-mssql"],
      "env": {
        "MSSQL_SERVER": "localhost",
        "MSSQL_USER": "your_user",
        "MSSQL_PASSWORD": "your_password",
        "MSSQL_DATABASE": "your_database",
        "MSSQL_TRUST_SERVER_CERTIFICATE": "true"
      }
    }
  }
}

From a local clone (run pnpm install && pnpm build first):

{
  "mcpServers": {
    "mssql": {
      "command": "node",
      "args": ["/absolute/path/to/mssql-mcp/dist/index.js"],
      "env": {
        "MSSQL_SERVER": "localhost",
        "MSSQL_USER": "your_user",
        "MSSQL_PASSWORD": "your_password",
        "MSSQL_DATABASE": "your_database",
        "MSSQL_TRUST_SERVER_CERTIFICATE": "true"
      }
    }
  }
}

Use node for local files. Avoid pnpm as the MCP command — extra output on stdout can break the protocol.

Confirm the install name matches npm: npm view @adriancy/mcp-mssql version.

Environment

All variables are read from the MCP process environment (e.g. Cursor env). Booleans treat 1, true, yes, on (case-insensitive) as true and 0, false, no, off as false. Invalid boolean and integer values fail startup validation.

Variable	Required	Default	Meaning
MSSQL_SERVER	yes	—	Hostname or IP of SQL Server
MSSQL_USER	yes†	—	Login user (SQL auth, NTLM, Azure AD password); not used for azure-active-directory-access-token or service-principal-only flows
MSSQL_PASSWORD	yes*†	—	Login password (*may be empty for some setups)
MSSQL_DATABASE	yes	—	Initial database
MSSQL_PORT	no	1433	TCP port; omit when using MSSQL_INSTANCE_NAME (driver uses instance + SQL Browser)
MSSQL_ENCRYPT	no	true	TLS encrypt: true, false, or strict (TDS 8.0 / tedious)
MSSQL_TRUST_SERVER_CERTIFICATE	no	false	Trust self-signed / skip cert validation (dev only)
MSSQL_TLS_SERVER_NAME	no	—	Hostname for TLS validation when it differs from MSSQL_SERVER (e.g. connect by IP)
MSSQL_TLS_CA_FILE	no	—	Path to CA PEM; passed via cryptoCredentialsDetails.ca
MSSQL_TLS_CERT_FILE	no	—	Optional client cert PEM (mutual TLS)
MSSQL_TLS_KEY_FILE	no	—	Optional client private key PEM
MSSQL_TLS_KEY_PASSPHRASE	no	—	Passphrase for encrypted client key
MSSQL_CONNECTION_TIMEOUT_MS	no	(driver default)	Pool connectionTimeout (ms). 0 → unset
MSSQL_DOMAIN	no	—	Domain login (config.domain for SQL auth; required for MSSQL_AUTH_TYPE=ntlm)
MSSQL_INSTANCE_NAME	no	—	Named instance (options.instanceName); do not rely on MSSQL_PORT with this set
MSSQL_MULTI_SUBNET_FAILOVER	no	false	Availability-group style failover hint
MSSQL_READ_ONLY_INTENT	no	false	Read-only routing for AG secondaries
MSSQL_MAX_RETRIES_ON_TRANSIENT_ERRORS	no	—	Tedious maxRetriesOnTransientErrors; 0 → unset
MSSQL_CONNECTION_RETRY_INTERVAL_MS	no	—	Tedious connectionRetryInterval; 0 → unset
MSSQL_POOL_MAX	no	10	Pool max connections
MSSQL_POOL_MIN	no	0	Pool min connections
MSSQL_POOL_IDLE_TIMEOUT_MS	no	30000	pool.idleTimeoutMillis
MSSQL_APP_NAME	no	—	options.appName (server tracing)
MSSQL_USE_UTC	no	true	options.useUTC when set
MSSQL_TDS_VERSION	no	—	7_1, 7_2, 7_3_A, 7_3_B, or 7_4
MSSQL_AUTH_TYPE	no	—	ntlm, azure-active-directory-password, azure-active-directory-access-token, azure-active-directory-service-principal-secret, or unset/default for SQL login
MSSQL_AZURE_CLIENT_ID	no‡	—	Azure AD app (client) ID where required
MSSQL_AZURE_TENANT_ID	no‡	—	Tenant ID (optional for password auth, defaults common; required for service principal)
MSSQL_AZURE_CLIENT_SECRET	no‡	—	Service principal secret
MSSQL_AZURE_ACCESS_TOKEN	no‡	—	Pre-obtained token for access-token auth
MSSQL_ALLOW_WRITES	no	false	If false/unset, blocks common write/DDL/exec patterns in mssql_query (heuristic only)
MSSQL_QUERY_TIMEOUT_MS	no	(driver default)	Request timeout in ms for the driver. 0 → unset

† Required for SQL authentication and for auth types that use interactive user login.
‡ Required depending on MSSQL_AUTH_TYPE; see .env.example. NTLM on Node 17+ may need --openssl-legacy-provider (see tedious FAQ).

See also .env.example.

Tools

Tool	Purpose
mssql_query	Run T-SQL; returns rows and rowsAffected
mssql_list_tables	Tables in INFORMATION_SCHEMA
mssql_describe_table	Column metadata

When MSSQL_ALLOW_WRITES is unset/false, obvious write/DDL patterns are blocked (heuristic only; use DB permissions for real safety).

Develop

pnpm install
pnpm check
pnpm test
pnpm build && pnpm start
pnpm dev

Use pnpm format to apply Biome formatting fixes and pnpm lint to run lint rules without formatting.

Use a read-only or least-privilege SQL login for day-to-day use.