MSSQL LocalDB MCP
Gives GitHub Copilot Chat (agent mode) — and any MCP consumer inside VS Code — full access to SQL Server Express LocalDB on Windows: manage instances, run any T-SQL script, discover loose .mdf/.ldf files in your project folders, and introspect schema.
The MCP server is a single native Rust binary bundled with the extension — no Python, .NET or Node runtime, no Docker, no download on first run.
Requirements
- Windows with SQL Server Express LocalDB installed (
SqlLocalDB.exe on PATH). LocalDB ships with Visual Studio and the SQL Server Express installer.
- VS Code 1.101 or later (MCP support).
Usage
After install, the server is registered automatically and shows up under MCP: List Servers as MSSQL LocalDB. Open Copilot Chat in agent mode and the localdb_*, sql_* and db_* tools are available — for example:
List my LocalDB instances and show the tables in the AppDb database.
Folder discovery (db_scan_folder) is allowlist-restricted and refuses to run until you allow at least one root. Run MSSQL LocalDB MCP: Open config.toml from the Command Palette and fill in:
# Windows paths in TOML need single quotes (literal string).
scan_allowlist = ['C:\Users\YourUser\source\repos']
scan_max_depth = 6
Claude Code CLI
VS Code registers MCP servers in-process, so the Claude Code CLI (in the terminal, or in the VS Code panel) does not inherit this extension's server — it reads its own config. Run MSSQL LocalDB MCP: Register with Claude Code CLI from the Command Palette to register it there too, reusing the binary already installed by the extension:
claude mcp add mssql-localdb --scope user -- "<extension>\server\mssql-localdb-mcp.exe"
Settings
| Setting |
Default |
What it does |
mssqlLocaldbMcp.serverPath |
(empty) |
Path to a custom mssql-localdb-mcp.exe. Empty uses the bundled binary. |
mssqlLocaldbMcp.logLevel |
info |
Server log level (stderr only). |
mssqlLocaldbMcp.queryTimeoutSeconds |
30 |
Default query timeout. |
mssqlLocaldbMcp.maxRows |
1000 |
Default row cap per query. |
Security
- Windows Integrated Authentication only — no SQL Auth, no password field anywhere.
- Every destructive action (
DROP, TRUNCATE, DELETE, ALTER, …) requires an explicit confirm: true — it never executes silently.
db_scan_folder only reads folders explicitly allowed in config.toml.
Full threat model: docs/SECURITY.md.
Documentation
License
MIT.
