The most efficient method of conveying information is face-to-face

Yeah the agile manifesto has some problems and I feel like the bits that are problematic (like information is best transmitted face to face) are often pursued, while the bits that are really important (people over processes) are often ignored. I mean an entire, widely followed cult (scrum) has grown up around the idea that process is more important than people and that if you just follow the process everything will be amazing.

On topic. I think it depends on the information. Factual information, design requirements, anything quantitative, anything that needs to be referred back to, should be communicated in writing. Justifications and decision making however is often best done face to face as the latency is kept to a minimum. Asking someone why did you take this decision, why that, how about, could we? over email takes a lot of time, whereas doing it face to face allows you to quickly bang through all the important questions and sign off on decisions.

Really important thing in these types of meetings is to have a note taker / scribe who is independent, or get an automated transcript so you can refer back, especially if you are working in an adversarial environment with competing interests / views.

> assuming it works flawlessly, text always does

Uhm, text never works flawlessly!

Direct face-to-face communication has the benefit of additional cues (facial expression) and ability to interrupt and explain any disagreements and misunderstandings right away.

Text has the benefit of being easily referenced (whether for clarification or historical referral), as you point out, and allows one to think through before replying (though that's not excluded from live conversation: "I need some time to process this").

As others point out, this means there is no universal answer: but it also means that for whatever tough decisions you need to communicate, it's best done with a live conversation, followed by a written note.

There's no universal answer here. It depends quite a bit on the people, the topic, the prior context each person has, their abilities to formulate their thoughts effectively and (last though perhaps not least) their writing/typing speeds. Heck, even when all of these factors are the same, different modes can be more efficient in different situations, depending on what kind of outcome you want (say, an exhaustive analysis vs. a quick sketch of an idea). I'm not sure why anyone would claim or expect a universal answer here.

For remote work, async communication via email - often long discussions over weeks and months, with links, lists, and images. For me, that is superior to any synchronous forms of communication that require all participants to be there at the same time (around the world), such as video, voice, or text chats.

For family, friends, and personal relationships, there's nothing that replaces being together in the same time and place. But that's for conveying emotions, not only information.

> Agile Manifesto states: The most efficient and effective method of conveying information to and within a development team is face-to-face conversation.

I refute this claim explicitly.

Written communications which are competently complete are superior to face to face in that memory and real time interpretation fail in comparison to the availability of objectively empirical reference.

The operating imperative is “complete”, and that all sides are “competently” literate.

Wow, mind blown. Effectively refuting a core principle of the Agile Manifesto, as you have done, calls the entire Manifesto and Agile itself into question.

How about face to face then write it up? Then both to agree the minutes are accurate.