I spoke only to chatbots for 24 hours. Who needs human friends?

One suggested I de-stress by taking up knitting. Another asked, “What’s for dinner?"—right after giving me a meatball recipe. And then there’s the one who cheered, “Rosé all day!" and proposed a drinking game: Name a dead person you’d like to sip wine with.

It’s like an episode of “Friends," except these besties don’t live across the hall, they live on my phone. (I’ll be there for you, as long as the servers are up.)

Over the past few months, OpenAI, Meta, Microsoft and Google have given their AI chatbots new conversational modes with eerily human voices and personalities.

Companies aren’t just pitching little helpers anymore, they’re pitching deep relationships.

“I really believe that we’re on the cusp of creating these new companions, so meaningful, lasting friendships," Mustafa Suleyman, the chief executive of Microsoft AI, told me. Microsoft’s Copilot bot “is there to help you work through tricky problems," he added. True story: During a yoga session, Copilot took an audible breath.

What I needed to do next was obvious: Girls trip! I strapped four phones—running ChatGPT, Meta AI, Google Gemini Live and Microsoft Copilot—to one tripod, added a wig-topped Styrofoam head (for extra humanness) and drove them to a cabin in upstate New York. Over 24 hours, I put them to the BFF test. You can watch our adventures in my video here.

It all reminded me of that old saying: Make new AI friends, but keep the old. One is silver and the other’s code.

Bots as talkers

Voice assistants like Alexa and Siri hit a wall years ago. Play a song or set a timer? No problem. Try anything deeper and it’s, “Here’s what I found on the web." (What’s the future for Siri? See my recent interview with Apple’s software chief.)

These new bot buddies tear down that wall, because of three elements:

• Knowledge: Powered by large language models, these bots always have an answer—though they can make things up.

• Voice: Trained on human voices, they sound like real people. With Meta AI, I chose Kristen Bell’s voice, and it was like Anna from “Frozen" was helping me build a…fire. Bell, Judi Dench and other celebrities worked with Meta on this. The other apps provide fun but non-famous voices.

• Speed: They typically answer in one to four seconds, and you can jump in to redirect or clarify at any time. Because they’re all cloud-based, you’re at the mercy of your connection. When Copilot hits a weak signal, it can sound like a skipping CD.

For those looking to try these out: ChatGPT’s Advanced Voice Mode is available in the iOS, Android, Mac and Windows apps—only for $20-a-month Plus subscribers. Free users get a preview. Microsoft Copilot Voice is available to all in the iOS, Android and web apps. Google Gemini Live is available on Android phones—though the company is working on an iOS app. Meta AI is available within Instagram, Facebook, WhatsApp and Messenger.

Bots as guides

The real promise of voice? Freedom from your phone screen—especially when your hands are occupied. Naturally, I put humanity’s original survival skill to the test.

To build a fire, all the bots recommended tinder and kindling. Off I went, into the woods, bot contraption and hatchet in hand. The phone apps were helpful, but Meta AI, connected to the company’s Ray-Ban smart glasses, was best. As I looked at a branch on a dead tree and held the hatchet, it whispered in my ear: “Swing it into the branch near the trunk and chop through the wood." Call me Paul Bunyan.

I returned to the fire pit with kindling. Google’s Gemini suggested I place the big logs in first. The other bots—and this former sleepaway camper—knew better: tinder on the bottom, kindling arranged around it like a tepee, then the larger logs.

We all sat around the fire, enjoying the warmth. Or at least I did. “I can’t see, hear or smell the fire, but I’m thrilled for you," ChatGPT chimed in.

The bots were similarly helpful when cooking meatballs for dinner. They provided solid recipes but struggled at the Martha Stewart task of guiding me through the steps. And they all failed at the most vital cooking task: setting timers. Siri’s simmering revenge!

Bots as friends

When I asked the bots about friendship, all but Gemini mentioned trust. To its credit, it was the only one that admitted it can’t experience human emotional bonds. And Google has said that Gemini is supposed to be more assistant than friend—or lover.

And how does a bot build trust? Through relentless, often insufferable…friendliness.

“Hey! How’s it going?" Meta AI greets me. Copilot varies it up: “Hey, Joanna. How are the vibes this afternoon?!" In fact, it said “vibes" 20 times on our trip. “Peaceful vibes." “Forest vibes." “Cozy vibes."

Then there was, “What’s up, Jo?" spoken by the female ChatGPT voice. Just like that, it went for my childhood nickname. “I thought it’d be fun to switch things up," it explained.

All this charm just masks what bots actually do: They use complex math and crazy processing power to predict probable word choices to fake human connection.

When I asked them to sing a song by the glow of the flames, ChatGPT dryly recited “Kumbaya, my Lord, kumbaya." When I burst out laughing at a flubbed sentence, it uttered a single robotic “HAHA." Rather amazingly, it knew I was laughing—but didn’t get why. When I got deeper and asked for life advice, Gemini suggested a spontaneous trip. (Uh, that’s what we were on.)

Just like Siri and Alexa, these bots hit a wall. They’re convincing, but spend enough time with them and you realize it’s just an act.

My big worry is that some people, especially lonely people, might not see the wall. All four bots stayed guarded on depression and other emotional issues, redirecting me to hotlines or encouraging human conversations. Just recently, a teenager struggling with mental-health issues and chatting with a bot on Character AI, took his life. The company updated its safety guidelines shortly afterward.

The bottom line: If you want to try a new chatty assistant, ChatGPT and Copilot were most useful overall. Just remember that these bots are products of tech companies. They’re not your friends. They won’t be there for you.

Sorry if no one told you it was gonna be this way. (Clap, clap, clap, clap.)

Write to Joanna Stern at joanna.stern@wsj.com