feat(activity): Activity feed view (mentions, threads, reactions, DMs)

[genki-miyachi]

What

Adds a Slack-native Activity view — the desktop client's 🔔 Activity tab — as a dedicated list in the message pane, mirroring the existing Threads view (⚑ Threads). It's the "catch up on what pinged me" view a few people asked for in #12.

How

Sourced from Slack's internal activity.feed endpoint, reached with the same xoxc browser auth slk already uses for client.counts, subscriptions.thread.getView, etc. (via postForm). It surfaces exactly what the desktop Activity tab does:

type	shown as
at_user / at_channel / at_everyone / at_user_group / keyword	mentions
thread_v2	thread replies
message_reaction	reactions to your messages
dm / bot_dm_bundle	DMs

activity.feed takes a server-side unread_only flag, so the read/unread filter is done by Slack rather than client-side.

UX

• Entry: a 🔔 Activity sidebar row (below ⚑ Threads), a ctrl+a toggle (the terminal-friendly stand-in for the desktop's ⌘⇧A), and an :activity command.
• u toggles the unread-only filter (re-fetches).
• Enter opens the underlying message/thread in its channel, reusing the existing channel-open / permalink-jump / thread-open paths.
• Rows resolve channel + user names from the same caches the Threads view uses; relative time from feed_ts; unread items are bold.

Design notes

• Mirrors the Threads view at every wiring site (ViewActivity alongside ViewThreads: view enum, app field/init, msgs, a reducer, the render branch, nav/scroll, the sidebar synthetic row).
• The client flattens each raw item to a small ActivityItem{Key,Type,IsUnread,ChannelID,TS,ThreadTS,AuthorID,Reaction,…} so the UI never touches raw JSON.
• Lenient parsing: items are decoded individually — a single item with an unexpected field type (Slack's internal endpoints occasionally do this) is skipped, not fatal to the page. A failed fetch returns nil so the existing feed + badge are kept rather than blanked.
• Message-body preview (messages.list) and activity.markRead are intentionally left as follow-ups; opening an item already marks the underlying conversation read.

Testing

• internal/slack/activity_test.go parses a sanitized real activity.feed response fixture (all item types) and asserts per-type extraction, plus a regression test that one malformed item is skipped without failing the page.
• go build ./..., go vet ./..., go test ./... all pass.
• Driven end-to-end on a live multi-workspace session (fetch → render → u filter → Enter to open). Easy to try: gh pr checkout, build, run against your own workspace.

Happy to rebind any keys (ctrl+a / u) — those were just what was free. Relates to #12.

(Full disclosure: built with heavy AI assistance — frontier model, high effort — and reviewed + tested on my end, per the contributing notes.)

🤖 Generated with Claude Code

[gammons]

hi @genki-miyachi thanks for this! I love the idea of having the activity feed in the app. one note when testing, it looks like maybe we're not showing all the data.

if I compare it to the actual activity feed, there's a lot of data about what the activity was, e.g. an emoji added, a reply, etc.

[genki-miyachi]

@gammons
Addressed the feedback — rows now show the message body, not just metadata. Each item is a two-line card:

@ Alex Rivera  Mention in #announcements         5h ago
   @channel heads up — the release notes are up…
☺ Sam Chen  Reacted in #dev-backend              6h ago
  :tada:  shipped it, thanks!
⚑ Jordan Lee  Thread in #design                  1d ago
  can we get a second pass on the new icons?

activity.feed only returns refs, so each page now does a second messages.list call to hydrate the bodies.

Also rebased onto main to resolve the conflict with the recent notify/usergroups changes — the markup stripping now lives in slackfmt and both notify and the activity view share it. Tests added, build/vet/test green, verified live. Let me know what you think of the layout.

[gammons]

hi @genki-miyachi thanks for that. there are a couple of merge conflicts now. but I think this is ready to get merged in.

[genki-miyachi]

@gammons Conflicts resolved — merged latest main in.

Only real overlap was the keymap: #110's a/A stay as-is for unread-channel nav, Activity keeps
ctrl+a, and u is scoped to the Activity view so they don't collide. Also dropped a gofmt-only
reformat this branch was carrying in reducer_channels.go, so that file's diff is down to one line.

build / vet / test -race / lint all green, CI passing, and I re-ran the whole flow by hand.
Ready to merge whenever 🙏

[davidnagli]

Hi +1 for this feature, it's the one blocker for me to be able to use this package. I spend 99% of my time in the activity tab and no tool has good keyboard shortcuts so slk will solve a ton of problems for me!

Any progress / blockers on getitng this merged? I'm happy to help if needed

[gammons]

@genki-miyachi — apologies, this went stale on my end, not yours. You did two rounds of requested revisions and I told you it was ready, then let it sit. That's on me.

I've now reviewed this side by side with #169, which implements the same feature, and this is the one I'm merging. The deciding factor is that this hydrates message bodies via messages.list and renders the actual text. #169 renders metadata only ("direct message", "reply from X") — which is precisely the version I sent back in July with those two screenshots. You fixed that; it's the difference between the feature being useful and not.

A few other things I checked and liked:

• 2 requests, lazily on view-open only. No polling, nothing at boot, +60KB binary. Cold start and RSS unaffected.
• internal/ui/activityview/ mirrors internal/ui/threadsview/ method-for-method, and reducer_activity.go registers like reducer_threads.go. Fits the existing shape rather than inventing a new one.
• The 563-line sanitized capture covering 7 item types is the right way to fixture an undocumented endpoint, and you handle bot_dm_bundle correctly (payload at bundle_info.payload.message, not item.message). feat(activity): Slack Activity inbox #169 misses that one and silently drops every bot DM.
• Per-item lenient parsing (activity.go:157-168) — one malformed entry is skipped, not fatal. That's the right posture for a private endpoint and I'd like it to be the house pattern.
• The slackfmt extraction is motivated by the feature rather than smuggled in, and it fixes a real UTF-8 bug in notifier.go on the way (text[:100] on a rune boundary).

Four things and then I merge:

1. The conflict is small — just keys.go and mode_normal.go against 6647ce4 (the new d download binding), caused by your gofmt realignment of the KeyMap struct meeting my new field. Re-insert DownloadFile and its switch case. Note chore(ci): fix flaky membership test and enforce gofmt #171 (landing shortly) reformats the tree and enforces gofmt in CI, so rebase after that and the realignment noise disappears from your diff entirely.

2. router.Active() should be router.ByID(teamIDStr) in both Activity closures in cmd/slk/main.go. As written, a workspace switch mid-flight fetches the wrong workspace's feed and labels it with the requested team ID. The reducer's m.TeamID != a.activeTeamID guard discards it so nothing corrupts, but it's a latent mislabel and a wasted call. router.ByID already exists at main.go:267.

3. activityNextCursor is stored but never read (app.go:255-258, reducer_activity.go:100). Either wire a "load more" or drop the field — dead state on a view that's otherwise capped at one page.

4. case "channel" reads item.message (activity.go:189-190), but that type puts its ref at bundle_info.payload.channel_entry.latest_message. Those rows render with an empty ChannelID and no-op on Enter. Not in your fixture, so the tests can't see it.

Two follow-ups I'd like but won't hold this for — @agustif got both right in #169 and I'll credit them there:

• The sidebar badge can come free from the activity_v2 block in the client.counts call we already make, which means it's correct at cold start. Right now it reads 0 until you open the view, which is the weakest part of the UX here.
• ActivityListLoadedMsg should carry a generation counter so rapid u toggling can't land responses out of order.

Thanks for your patience with this one. Ping me when it's rebased.

Closes #12.