Agent (Action Performer)

Agent (Action Performer) is a semantic role in SRL that identifies the performer of an action in a sentence: 'who does it'. Agent has the highest Salience in the role hierarchy.

A critical mistake is placing the central entity as Patient instead of Agent. In 'Cortisol is produced by the adrenal cortex', the agent is the adrenal cortex, NOT cortisol.

If you're writing about cortisol and cortisol sits in a passive role, the algorithm won't recognize it as the main character. In active voice: 'Cortisol originates in the adrenal cortex'. In SRL, Agent is like the lead role in a movie—if your entity plays an extra, the movie is about someone else.

In practice, focus on the first 2 paragraphs. Google reads the top of the page probabilistically. If your entity is a Patient there or hidden behind a pronoun, the rest of the text doesn't matter. Convert all passive constructions to active voice in the article lead.