A method for automatically determining query language operators of a Web information source, includes providing a set of known query operators, each known query operator in the set operating according to at least one syntax, wherein for a test query comprising a query operator and a test key word, each syntax of the operator produces a different number of document matches for the test query at a known Web information source; performing the test query on the Web information source, wherein the test query produces a number of document matches on the Web information source; comparing the number of document matches produced by the Web information source with the number of document matches produced by the known operator's different syntaxes; and using an established criteria for determining if comparing results indicate the Web information source supports the known query operator according its matching syntax.