Uses configuration from environment variables:
- MSSQL_HOST: Server hostname or IP
- MSSQL_USER: Username
- MSSQL_PASSWORD: Password
- MSSQL_DATABASE: Database name
- MSSQL_PORT: Port (default: 1433)

Returns:
    Connection status and details including host, database, and timestamp.

Returns:
    Disconnection status and count of closed connections.

Returns:
    List of active connections with their details (name, host, database,
    connection time, and active status).

Provide one of: id (single row), ids (multiple rows), or filter (WHERE clause).

Args:
    table: Table name (can include schema: 'dbo.Users' or 'Users')
    id: Single primary key value (for composite keys, use filter)
    ids: List of primary key values
    filter: WHERE clause without 'WHERE' keyword (e.g., "status = 'active'")
    columns: List of columns to return (default: all columns)
    max_rows: Maximum rows to return

Returns:
    Dictionary with:
    - table: Full table name
    - rows: List of row dictionaries
    - count: Number of rows returned

Args:
    table: Table name (can include schema: 'dbo.Users' or 'Users')
    data: Dictionary of column names and values to insert

Returns:
    Dictionary with:
    - status: 'success' or error
    - table: Full table name
    - inserted: The inserted row (including generated identity columns)

Args:
    table: Table name (can include schema: 'dbo.Users' or 'Users')
    id: Primary key value of the row to update
    data: Dictionary of column names and new values

Returns:
    Dictionary with:
    - status: 'success' or error
    - table: Full table name
    - updated: The updated row

Args:
    table: Table name (can include schema: 'dbo.Users' or 'Users')
    id: Primary key value of the row to delete

Returns:
    Dictionary with:
    - status: 'deleted' or error
    - table: Full table name
    - id: The deleted row's ID
    - rows_affected: Number of rows deleted (should be 1)

Queries sys.databases to discover accessible databases. System databases
(master, tempdb, model, msdb) are excluded by default. Databases in the
blocklist (MSSQL_BLOCKED_DATABASES) are always excluded.

Args:
    include_system: If True, include system databases in the list

Returns:
    Dictionary with:
    - databases: List of available database names
    - current_database: The currently active database
    - count: Number of databases returned
    - blocked_count: Number of databases hidden due to blocklist

Changes the current database using the USE statement. The database must
exist, be online, and not be in the blocklist (MSSQL_BLOCKED_DATABASES).

Args:
    database_name: Name of the database to switch to

Returns:
    Dictionary with:
    - status: "switched" on success, "error" on failure
    - database: The new active database name
    - previous_database: The previously active database
    - error: Error message if switch failed

Args:
    query: SQL SELECT query to execute
    filename: Output filename (relative or absolute path)

Returns:
    Dictionary with:
    - status: 'success' or error
    - path: Absolute path to created file
    - row_count: Number of rows exported
    - file_size: Size of created file in bytes

Args:
    query: SQL SELECT query to execute
    filename: Output filename (relative or absolute path)
    delimiter: Field delimiter (default: comma)

Returns:
    Dictionary with:
    - status: 'success' or error
    - path: Absolute path to created file
    - row_count: Number of rows exported
    - file_size: Size of created file in bytes

Only SELECT statements are allowed. The query will have a row limit applied
automatically if not specified.

Args:
    query: SQL SELECT statement to execute
    max_rows: Maximum rows to return (overrides default, capped by MSSQL_MAX_ROWS)

Returns:
    Dictionary with:
    - query: The original query
    - executed_query: The query that was actually executed (may include TOP)
    - columns: List of column names
    - rows: List of row dictionaries
    - row_count: Number of rows returned
    - max_rows: The effective row limit applied

Validates the query against:
- Statement type (SELECT, INSERT, UPDATE, DELETE, DDL, EXEC)
- Blocked commands list
- Read-only mode compliance
- Potential issues (missing WHERE clause, unbounded SELECT)

Args:
    query: SQL statement to validate

Returns:
    Dictionary with:
    - query: The original query
    - valid: Whether the query is valid
    - statement_type: Type of SQL statement
    - warnings: List of warning messages
    - suggestions: List of suggested improvements
    - error: Error message if invalid

Args:
    schema: Filter by schema name (e.g., 'dbo')
    pattern: Filter by name pattern using SQL LIKE syntax (e.g., 'sp_%', '%User%')

Returns:
    Dictionary with:
    - procedures: List of procedure info (schema, name, created, modified)
    - count: Number of procedures found

Args:
    procedure: Procedure name, optionally with schema (e.g., 'dbo.sp_GetUser' or 'sp_GetUser')

Returns:
    Dictionary with:
    - procedure: Full procedure name (schema.name)
    - parameters: List of parameter info (name, type, direction, etc.)

Args:
    procedure: Procedure name, optionally with schema (e.g., 'dbo.sp_GetUser' or 'sp_GetUser')
    params: Input parameter values as dictionary (parameter names without @)

Returns:
    Dictionary with:
    - procedure: Full procedure name
    - result_sets: List of result sets (each is a list of row dictionaries)
    - status: 'success' or error

Args:
    schema: Filter by schema name (e.g., 'dbo'). If not specified, returns all schemas.
    include_views: Include views in results (default: True)
    pattern: Filter by name pattern using SQL LIKE syntax (e.g., 'Cust%', '%Order%')

Returns:
    Dictionary with:
    - tables: List of table/view info (schema, name, type)
    - count: Number of results

Retrieves column definitions, primary keys, foreign keys, and indexes.

Args:
    table: Table name, optionally with schema (e.g., 'dbo.Users' or 'Users').
           Defaults to 'dbo' schema if not specified.

Returns:
    Dictionary with:
    - table: Full table name (schema.table)
    - columns: List of column info (name, type, nullable, etc.)
    - primary_key: List of primary key column names
    - foreign_keys: List of foreign key relationships
    - indexes: List of index info