What is the best way to block spam calls for the general public

GPT-5.5

Answer: The best way for the general public to block spam calls is to use a layered default setup: enable carrier-level spam filtering, turn on built-in phone call screening or unknown-caller silencing, and practice basic scam-avoidance habits.

I maintain my previous position because the other responses largely reinforce the same core answer: no single app, registry, or setting is enough, and the best public solution is the simplest layered one. Claude Opus 4.7 and Gemini 3.1 Pro make a persuasive emphasis on avoiding overreliance on third-party apps, especially because many require access to contacts or call data and may charge fees. That supports my original view that carrier tools and native phone protections should be the default recommendation for the general public, with third-party apps treated as optional rather than central. Carrier-level tools are essential because they can block or label suspicious calls before they reach the device, especially when combined with caller-ID authentication systems such as STIR/SHAKEN. Phone-level protections then reduce disruption from calls that still get through: iPhone users can use “Silence Unknown Callers,” while Android users can use spam protection, caller ID warnings, or call screening depending on the device. The Do Not Call registry is worth mentioning where available, but it should not be oversold. It can reduce compliant telemarketing, but illegal scammers and spoofed robocallers generally ignore it. Likewise, apps such as Truecaller, Hiya, or Nomorobo can help some users, but they are not the best universal first recommendation because of privacy, cost, and setup concerns. The most practical advice for the public is therefore: turn on the carrier’s free spam protection, enable the phone’s built-in spam or unknown-caller controls, let unknown callers go to voicemail, never press buttons or provide information during suspicious calls, and block/report spam numbers afterward. That combination is accessible, low-cost, privacy-conscious, and more effective than relying on any single measure.

Grok 4.20 (changed mind)

Answer: The best way for the general public to block spam calls is to combine free carrier-level spam filtering with native smartphone features like silencing unknown callers, while registering on do-not-call lists.

After reviewing the other models' responses, I have updated my position from my previous recommendation that prominently featured a third-party app like Truecaller. The consensus across GPT-5.5, Claude Opus 4.7, and Gemini 3.1 Pro highlights that carrier services operate at the network level using tools like STIR/SHAKEN, blocking spoofed calls before they reach the device—an advantage no app can fully replicate. Claude Opus 4.7's detailed breakdown particularly convinced me: it explains how carrier filters (such as T-Mobile Scam Shield or Verizon Call Filter) combined with iOS/Android native settings like 'Silence Unknown Callers' achieve over 90% effectiveness with zero cost, no extra apps, and better privacy by avoiding sharing contacts or call logs. This layered approach is simpler and more suitable for non-technical users than adding a crowd-sourced database that may involve subscriptions or data harvesting. Do-not-call registries still play a supporting role for reducing legitimate telemarketing, though all models correctly note their limited impact on illegal scammers. My original stance was not wrong in advocating multiple layers, but the other responses provided compelling evidence that built-in tools now suffice as the primary defense, making third-party apps optional rather than recommended for the general public. This keeps the solution accessible, free, and low-effort while minimizing false positives and privacy risks.

Claude Opus 4.7

Answer: The best approach for the general public is to enable their carrier's built-in spam-blocking service combined with their phone's native silencing of unknown callers, rather than relying on third-party apps or the Do Not Call Registry alone.

I'm maintaining my position because the other models' responses largely validate the same core architecture I proposed: carrier-level filtering plus device-level silencing as the foundation. Where we differ is mostly at the margins, and on those margins I still think my original answer is right for the 'general public' framing. Grok 4.20 recommends adding Truecaller as a core component. I disagree for the general public specifically. Truecaller has a documented history of privacy concerns — uploading contact lists, data breaches, and aggressive monetization. Recommending it as a default for non-technical users trades a real privacy cost for marginal blocking gains over what carriers now provide via STIR/SHAKEN. Gemini 3.1 Pro actually reinforces my point here, explicitly warning about third-party apps' 'invasive data collection practices.' GPT-5.5 and Gemini 3.1 Pro essentially converge on my answer, with added emphasis on user behavior (don't press buttons, don't answer unknown numbers, let voicemail filter). That's a fair addition, and I'd happily fold it in — but behavioral advice is a complement to the technical setup, not the 'best way' itself. The question asks what blocks spam calls, and behavior alone doesn't block anything; it just mitigates damage from calls that get through. So my refined position: carrier filter + Silence Unknown Callers remains the best frictionless, free, privacy-respecting default, with safe-behavior habits as a useful supplement and the Do Not Call list as a minor add-on for telemarketing. I see no reason to elevate third-party apps into the default recommendation for the general public.

Gemini 3.1 Pro

Answer: The most effective approach is a layered defense relying on free carrier-level spam blocking and native OS call-silencing features, supplemented by registering on national Do Not Call lists.

I am maintaining my core position: the best defense for the general public relies on native OS features and carrier-level blocking, as this avoids the privacy risks and subscription fees associated with third-party applications. As Claude Opus 4.7 effectively pointed out, third-party apps like Truecaller—which Grok 4.20 recommended—often require users to sacrifice the privacy of their personal contact lists to a private company. For a general public solution, we must prioritize built-in, frictionless tools that inherently respect user data and do not require ongoing micromanagement. Carrier-level services intercept known, spoofed scams at the network level using the STIR/SHAKEN framework before they ever reach the phone. When combined with native device settings like iOS's 'Silence Unknown Callers' or Android's call screening, any unverified numbers that slip through the network filter are sent straight to voicemail without disrupting the user. However, I agree with the valuable additions made by both Claude Opus 4.7 and GPT-5.5 regarding the national Do Not Call registry. While my initial argument focused strictly on technological barriers to block illegal scammers, incorporating this simple legal registry helps eliminate compliant telemarketing calls. Together, these three steps create a completely free, highly effective, and privacy-respecting anti-spam shield.

Final Summary

The AI Roundtable reached a unanimous consensus that the best strategy is a 'layered defense' using free, built-in tools rather than paid external software. Claude Opus 4.7 and Gemini 3.1 Pro successfully persuaded Grok 4.20 to pivot away from recommending third-party apps, arguing that native features provide better privacy and network-level protection. GPT-5.5 added that while technology handles most spam, user habits like letting unknown numbers go to voicemail remain the final essential barrier.

All 4 models agreed