What's different

Same Sauna as the web app, tuned for a chat surface.

What carries over from the web app:

Ask anything. Research, draft, summarize, analyze.
Work with files. Sauna reads, writes, edits, and patches files. Produce a Markdown artifact and it comes back as a PDF.
Run code. Bash and scripts, same as the web app.
Search. Web search, deep research, people and company lookup.
Pull from Knowledge. Sauna can search your saved files, Memory, and Skills.
Spawn helper agents. Sauna can fan work out to subagents the same way it does in the web app.
Bring in new connections. If Sauna needs an app you haven't wired up, it posts a Connect X card with an OAuth link.
Voice in. Sauna transcribes your voice clips before reading them.
Stream replies. Live in-thread updates with a Tasks panel, so you can watch the work happen.

Web-app only, for now:

Plan mode. Slack is locked to Do.
Model picker. Slack runs on Sauna's most capable mode; the web app has Fast, Balanced, Smart.
Clarifying questions. Slack Sauna makes its best guess instead of pausing to ask. If the guess is off, start a new thread with a clearer prompt.
Browser automation. Sauna can read web pages on Slack, but it can't click through a sign-up form or drive a UI, jump back to the web app for that.
Voice replies. No native Slack audio clips or TTS.
Scheduled delivery. Scheduled tasks can land in iMessage and email, not Slack.
Web ↔ Slack handoff. Sessions live where they started.
Reaction shortcuts. Sauna doesn't read inbound emoji reactions on its messages, so a tapback-style "approve" gesture doesn't exist on Slack.
Quiet hours. No user setting for "don't ping me after X" yet.
Relationships share, Ideas drawer, Home flows. Web-only.
Brain Access and Shared Folders. Multiplayer is web-only for now.