MCP tools reference

The syntaqlite MCP server exposes three tools. It is built into the syntaqlite binary and runs over stdio via syntaqlite mcp.

For setup instructions, see MCP server setup.

`format_sql`

Format a SQL string.

Parameter	Type	Default	Description
`sql`	string	(required)	The SQL to format
`line_width`	integer	`80`	Maximum line width
`keyword_case`	string	`"upper"`	`"upper"`, `"lower"`, or `"preserve"`
`semicolons`	boolean	`true`	Append trailing semicolons

Returns: The formatted SQL as a string. On parse error, returns "Error: <message>".

Example input:

{
  "sql": "select a,b from t where x=1",
  "line_width": 80,
  "keyword_case": "upper"
}

Example output:

SELECT a, b FROM t WHERE x = 1;

`parse_sql`

Parse a SQL string and return its AST as an indented text dump.

Parameter	Type	Default	Description
`sql`	string	(required)	The SQL to parse

Returns: A text representation of the abstract syntax tree. On parse error, returns "Error: <message>".

Example input:

{
  "sql": "SELECT id FROM users"
}

Example output:

SelectStmt
  flags: (none)
  columns:
    ResultColumnList [1 items]
      ResultColumn
        flags: (none)
        alias: (none)
        expr:
          ColumnRef
            column: "id"
            table: (none)
            schema: (none)
  from_clause:
    TableRef
      table_name: "users"
      schema: (none)
      alias: (none)
      args: (none)
  where_clause: (none)
  groupby: (none)
  having: (none)
  orderby: (none)
  limit_clause: (none)
  window_clause: (none)

`validate_sql`

Check whether a SQL string is syntactically valid.

Parameter	Type	Default	Description
`sql`	string	(required)	The SQL to validate

Returns: A JSON string with two fields:

Field	Type	Description
`valid`	boolean	`true` if the SQL parsed without errors
`errors`	string	Error messages (empty string if valid)

Example (valid SQL):

{"valid": true, "errors": ""}

Example (invalid SQL):

{"valid": false, "errors": "error: syntax error near 'SELEC'\n --> <stdin>:1:1\n  |\n1 | SELEC 1\n  | ^~~~~\n0 statements parsed, 1 errors\nerror: 1 syntax error(s)"}

Note: validate_sql checks syntax only (successful parse). It does not run semantic analysis (unknown table/column detection). For schema-aware validation, use the CLI directly:

syntaqlite validate schema.sql