Mssql safe

MSSQL Safe

Generic Microsoft SQL Server skill with UTF-8 JSON output, read-only query guards, timeout and row limits, and an intentionally gated exec command.

Configuration

Use standard environment variables or global flags:

Variable	Flag	Default
MSSQL_HOST	--host	none
MSSQL_PORT	--port	1433
MSSQL_DATABASE	--database	none
MSSQL_USER	--user	none
MSSQL_PASSWORD	none	empty
MSSQL_ENCRYPTION	--encryption	require
MSSQL_TDS_VERSION	--tds-version	driver default
MSSQL_APPNAME	--appname	mssql-safe
MSSQL_ALLOW_WRITE	none	false

MSSQL_ENCRYPTION accepts default, off, request, or require.

Never pass a password as a CLI argument. Inject MSSQL_PASSWORD from a secret manager.

Secret setup

Before configuring credentials, ask which secret manager and local profile the user wants. Follow Secure secret profiles. Do not invent or publish profile names, hosts, templates, or secret references. If the user asks for the author's method, use a per-profile Proton Pass pointer file with process-scoped pass-cli run. Never request or display resolved values.

Run

From this skill directory:

uv run --python 3.13 --with pymssql python scripts/ms.py query --sql "SELECT @@VERSION AS version"
uv run --python 3.13 --with pymssql python scripts/ms.py query --sql @report.sql --params '[42, "active"]'
uv run --python 3.13 --with pymssql python scripts/ms.py list-databases
uv run --python 3.13 --with pymssql python scripts/ms.py list-schemas
uv run --python 3.13 --with pymssql python scripts/ms.py list-tables --schema dbo
uv run --python 3.13 --with pymssql python scripts/ms.py describe-table --schema dbo --table users

Global flags go before the subcommand:

uv run --python 3.13 --with pymssql python scripts/ms.py \
  --host db.example.net --database app --user app_reader --encryption require \
  query --sql "SELECT TOP 10 * FROM dbo.users"

--sql accepts a literal string, @file.sql, or - for stdin. --params accepts a JSON array or object, also from @file.json or stdin.

Controlled write mode

exec is disabled unless both checks pass:

1. environment variable MSSQL_ALLOW_WRITE=true
2. CLI flag --confirm-write

Example:

MSSQL_ALLOW_WRITE=true uv run --python 3.13 --with pymssql python scripts/ms.py \
  --host db.example.net --database app --user app_writer \
  exec --confirm-write --sql "UPDATE dbo.jobs SET status = 'done' WHERE id = 42"

Server permissions are the real authorization boundary. The client gate is only defense in depth.

Safety contract

• Read commands allow only obvious read-only statements such as SELECT, WITH, and VALUES.
• Multiple statements and obvious DDL, DML, and administrative keywords are rejected for read commands.
• Read commands connect with SQL Server read-only intent, set a lock timeout, and cap fetched rows.
• exec rejects empty or multi-statement input and never runs unless both write gates are enabled.
• Do not print secrets, connection strings, or environment variables.
• Ask before touching sensitive datasets, even for read-only work.

Output

Successful commands return JSON:

{
  "rows": [{"name": "master"}],
  "row_count": 1
}

Binary values are hex encoded. Dates, times, decimals, UUIDs, lists, and dictionaries are converted to JSON-safe values.

Tests

uv run --python 3.13 --with pymssql python tests/test_ms.py