local-mysql MCP Server

This is a local development MCP server that exposes FO MySQL databases to VSCode (and Copilot CLI). It provides two tools: query (SELECT only) and execute (INSERT / UPDATE only).

This server is for local development only. Do not deploy to production environments or connect to production databases.

Connection Settings

The default values are aligned with src/main/resources/application.yml.

The connection pool is schema-agnostic and does not bind to a default database. Specify the schema using the schema parameter for each call, or use fully qualified names like oa.t_xxx. Allowed schemas: fo, oa, bo, cm, nepro.

Related MCP server: MySQL MCP Server

Installation and Build

cd mcp-server
npm install
npm run build

After building, restart your MCP client (VSCode / Copilot CLI) to reload the configuration.

For iterative development without rebuilding:

npm run dev

Tools

query — Read-only SELECT

{
  "sql": "SELECT id, name FROM m_article WHERE id = ?",
  "params": [123],
  "schema": "fo"          // 省略可
}

Return value:

{
  "schema": "fo",
  "rowCount": 1,
  "truncated": false,
  "maxRows": 1000,
  "fields": [{ "name": "id", "type": 3 }, { "name": "name", "type": 253 }],
  "rows": [{ "id": 123, "name": "..." }]
}

Constraints:

• Single statement only (multiple statements are rejected)

• Must start with SELECT (CTE / WITH is not supported in v1)

• Result limit: 1000 rows. If truncated: true, it indicates that more rows exist.

execute — INSERT or UPDATE

{
  "sql": "UPDATE m_article SET name = ? WHERE id = ?",
  "params": ["new name", 123],
  "schema": "fo"
}

Return value:

{
  "schema": "fo",
  "affectedRows": 1,
  "insertId": 0,
  "changedRows": 1,
  "warningStatus": 0
}

Constraints:

• Single statement only

• Must start with INSERT or UPDATE

• DELETE, DROP, ALTER, CREATE, TRUNCATE, RENAME, GRANT, REVOKE, REPLACE, MERGE, CALL, LOAD, HANDLER, LOCK, UNLOCK, SET, USE, START, BEGIN, COMMIT, ROLLBACK, SAVEPOINT — all rejected

Integration

Clone this repository alongside the project that will use this server, and set up the directory structure as follows:

parent/
├── mcp-local-mysql/        ← このリポジトリ
└── your-project/
    └── .vscode/mcp.json    （Copilot CLI の場合は .mcp.json）

VSCode

Add .vscode/mcp.json to the root of your project. The root key is servers:

{
  "servers": {
    "local-mysql": {
      "command": "node",
      "args": ["../mcp-local-mysql/dist/index.js"],
      "env": {}
    }
  }
}

To override credentials per workspace, edit the env object. Example:

"env": { "FO_DB_USER": "devuser", "FO_DB_PASS": "devpass" }

Also, ensure MCP discovery is enabled in .vscode/settings.json so that VSCode recognizes .vscode/mcp.json:

{
  "chat.mcp.discovery.enabled": true
}

Copilot CLI

Add .mcp.json to the root of your project. The root key is mcpServers:

{
  "mcpServers": {
    "local-mysql": {
      "command": "node",
      "args": ["../mcp-local-mysql/dist/index.js"],
      "env": {}
    }
  }
}

Security Notes

• multipleStatements: false is set at the driver level (defense-in-depth added to the validator)

• All queries are parameterized — values must always be passed via params and never embedded directly into the SQL string

• Schema names are matched against a whitelist before being embedded into USE `...`

• Server logs are output only to stderr. stdout is reserved exclusively for the MCP protocol frames