How many letters does the top answer for “wrote the glass key” have?

The most common answer is hammett (7 letters).

Crossword clue: wrote the glass key

1 answer found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

hammett 7 letters wd-fact-v3

United States writer of hard-boiled detective fiction (1894-1961)

wrote glass 67% similar → shyamalan

author of the glass key 50% similar → hammett

wrote the glass menagerie 50% similar → williams