I think the best answer around here is a careful explanation that can be summed up as "it depends". It depends on what is expected of that role at any given organization. And whatever the answer to that, the likelihood that the role highly depends on efficient communication, mediation between parties (multi-stakeholder approach and so on), the best tool is probably Thunderbird, or Office, or whatever floats one's boat.
Of course, at some point said Architect usually have to manage technological aspects, decisions, problems, projects - and for that the best tool is again "it depends", just like in any engineering endeavor. And yes, it might include a few sleepless nights doing low-level R&D, looking over code, fiddling with components, getting to the bottom of bugs, coming up with workarounds, strategy, proposals - or evaluating them, soliciting feedback, reviewing it et cetera.
And so, it depends, I might have been.
(But seriously, I usually found, that those high level tech decision makers/influencers who are not communicating enough, who are not organizing information enough, but are too lost in some specialized tool, to be completely useless. I use Google Docs and Spreadsheets to track things, because it can be easily and kind of "safely" shared with the required folks. Whereas every other tool is too slow. JIRA? Oh, that only works on the internal network, better wait months for VPN access. Oh here's a .xlsx attached to an email, fuck the actual devs that don't live on Office, and so on.
And on top of all that an "architect" is - at least in my experience - is a thankless job. Not high-profile enough to actually have authority to effect change, but usually sufficiently high on the ladder to get flak for any and all problems.
Finally, in large orgs it's not rare that the Architect role is the last line that has at least some connection to the actual tech/development, and up from there it's all about costs, headcount, opex/capex, schedules, compliance, governance, PR, and internal/external politics/sales/optics. And this makes it neigh impossible to execute well.)
