Superhuman vs Slack
Side-by-side trajectory, velocity, and editorial themes.
Inbox becomes an MCP endpoint — agents now drive Superhuman alongside humans, in your voice.
Superhuman ships at very high cadence, mixing mobile polish (Quick Reply from notifications, calendar widget, Split Inbox reorder/hide) with category-shifting AI work. The April MCP launch turned Superhuman Mail into a callable surface for Claude, ChatGPT, and other assistants, with 'uniquely Superhuman' actions (Smart Send, Read Statuses, Split Inbox triage) exposed as tools. Draft Sync with Gmail/Outlook bridges the agent ecosystem further: assistants can draft anywhere, you review and send in Superhuman.
The product is moving from 'fast email for power users' to 'AI-and-humans share the inbox.' Personalization, Write with Voice, and MCP form a clear stack — voice in, agent action, voice out — with the original power-user keyboard-shortcut audience preserved through continued Split Inbox refinement. Mobile gets weekly polish to keep that surface from rotting while the AI direction takes the headlines.
Next likely move is delegated-inbox MCP actions for executive assistants (act-as-on-behalf permissions) and recurring agent tasks tied to Personalization rules. A cross-app demo — Superhuman + Granola + a calendar tool, all via MCP — is the obvious narrative the May 21st virtual event has been set up to deliver.
Slack rebuilds its developer platform around shipping in-channel AI agents.
Slack is well into a platform pivot, restructuring its CLI, Block Kit, and APIs around AI agent use cases. The 4.0.0 release in April formalized this with an agent-scaffolding command, sample agent apps, and a live-reloading dev workflow. Recent additions — streaming chat APIs, Card/Carousel/Alert blocks, and continued MCP server expansion — show the surface area for in-Slack agents widening fast.
The platform is shifting from 'agents can post messages' to 'agents are first-class UI citizens'. The new chat.startStream / chat.appendStream / chat.stopStream methods change what an agent reply looks like, and the Card and Carousel blocks hint at richer multi-turn agent flows. Security work on PKCE and optional scopes is keeping pace, which tells you third-party agent developers are the audience, not just first-party features.
Expect Slack to publish reference agents and likely a discovery or marketplace surface for agent apps within the next minor cycle, with streaming Block Kit becoming the canonical pattern shown in the docs.
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