Interact
Interact opens its intranet to outside AI assistants and uses Claude to attack its own platform.
Comparison · Collab
Capacities vs Slack
A side-by-side editorial comparison of Capacities and Slack — release velocity, themes, recent moves, and the top alternatives to consider.
Capacities vs Slack: at a glance
What is Capacities?
Capacities rebuilds its tablet app and moves audio recording down to Pro.
Capacities ships a named release about monthly. November's rebuilds the iPad and Android tablet app, moves audio recording and analysis into the Pro plan, and starts reminders in early testing for Believer subscribers. October added whiteboards and a global graph view, and September brought audio transcription and AI chats that can edit objects.
What is Slack?
Slack now hosts any A2A agent without Slack-specific code.
Slack's developer channel is almost all agent plumbing. On 10 November Slack became an A2A (Agent2Agent) client: a team hosts its own agent, publishes an Agent Card, and Slack calls it when people talk to it, with no request URL, event handling or Slack-specific logic. This follows Slackbot skills managed through Web API methods, a Slack CLI that points coding agents to the Slack MCP server, and a new requirement that Work Objects embeds allow the slack-mcps.com frame ancestor.
Capacities vs Slack: editorial side-by-side
Capacities
5.0COLLAB
Capacities rebuilds its tablet app and moves audio recording down to Pro.
◆ Current state
Capacities ships a named release about monthly. November's rebuilds the iPad and Android tablet app, moves audio recording and analysis into the Pro plan, and starts reminders in early testing for Believer subscribers. October added whiteboards and a global graph view, and September brought audio transcription and AI chats that can edit objects.
◆ Where it's heading
Capacities keeps a pattern of trialling features with Believers and then moving them down to Pro, as it did with bulk import, image analysis and now audio. The tablet rebuild suggests more attention to devices beyond desktop.
◆ Prediction
Reminders will likely leave Believer-only testing in a coming monthly release and move toward Pro, following the audio path.
Slack
6.3COMMSCOLLAB
Slack now hosts any A2A agent without Slack-specific code.
◆ Current state
Slack's developer channel is almost all agent plumbing. On 10 November Slack became an A2A (Agent2Agent) client: a team hosts its own agent, publishes an Agent Card, and Slack calls it when people talk to it, with no request URL, event handling or Slack-specific logic. This follows Slackbot skills managed through Web API methods, a Slack CLI that points coding agents to the Slack MCP server, and a new requirement that Work Objects embeds allow the slack-mcps.com frame ancestor.
◆ Where it's heading
Slack is lowering the cost of putting outside agents in front of its users: first skills as code, then MCP pointers for coding agents, now a standard protocol in place of the Slack app model for agents. The platform is positioning itself as the place where agents built anywhere meet the people who use them.
◆ Prediction
Expect more A2A follow-ups, such as agents appearing in Slackbot or skills surfaces and richer Agent Card features, given how fast the agent releases have stacked up since October.
Capacities alternatives
Other Collab products tracked by Sparkpulse, ranked by recent ship velocity. Tap any card for the full editorial trajectory or compare directly with Capacities.
Nextcloud
Nextcloud's November patches lean on preview speed and sharing fixes across three branches.
Mattermost
Mattermost v12.1 puts bots and burn-after-reading messages under the same access rules.
Asana
Asana lets Division admins run their own custom roles, on top Enterprise plans only.
Double
Double turns a recorded Chrome session into an agent that repeats the task.
SiYuan
SiYuan 3.8.11 alphas add freeform mind maps and plugin snapshots right after 3.8.10.
Slack alternatives
Other Collab products tracked by Sparkpulse, ranked by recent ship velocity. Tap any card for the full editorial trajectory or compare directly with Slack.
Rspamd
Rspamd 4.3 fixes SPF evaluation order and rejects weak DKIM keys, with results that change.
Twilio
Twilio's voice AI stops cutting callers off mid-sentence, using its own turn-taking model.
Salesmsg
Salesmsg adds call-back requests and a one-click Emergency Stop for all outbound texts.
Element
Element 1.12.35 follows the call picture-in-picture release with one desktop storage fix.
Krisp
Krisp moves call transcripts and live captions to cloud transcription in KrispCX 2.84.4.
Misskey
Misskey 2026.11 ships: a leaner start script, and Node.js 22 no longer boots.
Recent activity from Capacities and Slack
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 4d agoSlackBring your A2A agents to Slack ⚡
- 8d agoSlackWork Objects embeds require the slack-mcps.com frame ancestor
- 9d agoCapacitiesA rebuilt tablet app, audio in Pro, and reminders in early testing
- 10d agoSlackSlack CLI 4.13 tells coding agents about Slack MCP and Skills
- 10d agoSlackSlack Skills Plugin installs in Claude Code from its own marketplace
- 12d agoSlackUpdated low-usage submission criteria for Slack Marketplace apps
- 15d agoSlackSlack CLI 4.12.0, the fourth CLI release in October
- 19d agoCapacitiesWhiteboards, global graph view, and polish on the basics
- 1mo agoCapacitiesAudio recording and transcription, a calmer desktop, bulk property editing, and smarter AI chats
- 2mo agoCapacitiesv1.70.2: Index Card padding and calendar fixes
- 2mo agoCapacitiesPDF reader view and annotations for Believers, Version History, more calendars, and AI image generation
- 2mo agoCapacitiesCapacities Pro+ and Believer+
Frequently asked questions
What is the difference between Capacities and Slack?
They serve adjacent needs but don't currently overlap on shipped themes. Slack is currently shipping more aggressively (velocity 6.3 vs 5.0), with 1 editorial sparks in the last 30 days against 0. See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is Capacities better than Slack?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. Slack is currently shipping more aggressively (velocity 6.3 vs 5.0), with 1 editorial sparks in the last 30 days against 0. For your specific use case, the alternatives sections above list other Collab products to evaluate alongside.
What are the best alternatives to Capacities?
Top Capacities alternatives in Collab are ranked by recent ship velocity. Browse the "Capacities alternatives" section above for the current picks, or visit /alternatives/capacities for the full list with editorial commentary on each.
What are the best alternatives to Slack?
Top Slack alternatives in Collab are ranked by recent ship velocity. Browse the "Slack alternatives" section above for the current picks, or visit /alternatives/slack for the full list with editorial commentary on each.