So far they've been very consistent in using feminine forms with the female voice.
I wrote אני מתקנת את and it says I missed a space. That seems like an odd response.
In Dov's case I refer to the task of writing down the audio. If you want to say אני מתקנת את הנעל שלי then you are right - it is a very good translation of "I repair my shoe".
However, the sentence אני מתקנת הנעל שלי is grammatically incorrect, since the show is an indirect object, and needs the word את.
You meant to type "the shoe is a definite direct object." [It is the definite direct objects that must be preceded by "et" in Hebrew.] In case someone else read this and needs examples, in "I gave her my book" and "I gave her the book" the word "book" is the direct object (also known as the accusative) and is definite, which would need "et" in Hebrew. The word "her" is the indirect object (also know as dative). But "I gave her a book" would not use "et" because it is indefinite ("a" instead of "the" or "my").
Is it the same word for "fix" ? or does it specifically mean "repair" as in repairing a building ?