By Leslie Kwoh and Lauren Weber

Want that job? Better be nice to the receptionist.

Job seekers might not know it, but an interview often begins the moment they walk through the door. Candidates usually save their “best behavior” for the hiring manager and assume administrative assistants are automatons whose opinions don’t matter.

But assistants are not only close to the boss, they’re generally sharp observers who can instantly sense whether someone will fit in with company culture, says Karlena Rannals, president of the International Association of Administrative Professionals, which represents 21,000 members.

It’s just one way companies are filtering candidates in a tight labor market where more applicants are vying for fewer openings, experts say.