The analysis of «ما أنا قمت» requires a distinction between the grammatical agent and the person to whom an action is assigned in meaning. The verb «قمت» already contains an agreement marker referring to its agent, whereas the overt «أنا» may function as the subject of a nominal sentence.
TermQuestion it answers
Grammatical agentWhich element functions as the verb's formal subject?
Semantic agentTo whom is the action actually attributed?
MubtadaʾWhich nominal subject receives the predicate?
Confusing these roles makes it too easy to derive restriction from a mere change in sentence format.