Why is it safe?
Laptops and keyboards are not toxic and carry no meaningful chemical hazard for cats. The primary appeal is thermal, cats are attracted to the warmth generated by running electronics. Electrical risk is negligible because cats interact with the external casing, not exposed conductors. Normal cat behavior (sitting on, walking across, rubbing against) produces no health risk.
Symptoms
None from normal contact. Theoretical: a cat that chews a loose keyboard key could ingest a small plastic component (see Plastics & Rubber category for physical hazard assessment).
What To Do
No action needed for normal cat-laptop interaction. Note: prolonged obstruction of laptop vents by a sleeping cat can cause device overheating (a device protection concern, not a health concern for the cat).
Notes
A cat sitting on a running laptop gets a localized, mild heat source, similar in effect to a warm surface or low-setting heated blanket. The only genuine risk escalation occurs if a cat chews a charging cable connected to the device (see Electrical Cables entry, HIGH risk) or if a laptop battery is physically punctured (lithium battery thermal runaway). Normal non-chewing interaction with the device body is LOW risk. The very common behavior of cats sitting on keyboards during video calls is behavioral, not a safety concern.
Sources
→ ASPCA Animal Poison Control Center — aspca.org
→ VCA Animal Hospitals — vcahospitals.com