feat(canvas): context onboarding with a slack-style channel intro by adamleithp · Pull Request #3370 · PostHog/code

adamleithp · 2026-07-12T22:55:07Z

Problem

Contexts had no guided creation flow and their feed was task cards only — no lifecycle announcements, no sense of who created a context or how to give it a CONTEXT.md.

Changes

Slack-style channel intro (ChannelIntro, new)

Every public context's feed opens with a pinned intro: the context name, "@ann created this context today. This is the very beginning of the mobile context." (creator name rendered as a mention chip, inert for now), derived entirely from the backend channel row — so it renders identically for every teammate and for pre-existing contexts.
Below it, a context.md card with two states: a pressable "Create a context.md" call to action (lucide file-plus-corner) that opens the describe dialog, flipping to an inert tone=success "Created context.md" card (file-check-corner) once instructions exist.
A "Learn more about contexts" card sits alongside (placeholder — not wired to a destination yet).

Create dialog split into two modes (CreateChannelModal)

Create mode is name-only: creates the context and lands you in its feed. No session starts at creation; onboarding continues from the intro card.
Describe mode ("Create your context.md", opened from the intro card or the CONTEXT.md empty state's "Build with agent") is a single textarea that seeds the plan-mode session which co-builds CONTEXT.md and publishes via the PostHog MCP.

Feed opener + system rows (ChannelFeedView, useChannelFeedMessages)

The derived opener row is now the Slack-style "joined mobile", rendered as the creator (initials avatar + name) instead of the robot "PostHog / Agent" chrome; agent lifecycle rows ("is building CONTEXT.md…") keep the agent chrome.
ChannelFeedView gains an intro slot rendered above the first entry; when set, the feed renders even with zero entries, so new public contexts show intro + Today marker + joined row instead of the suggestions empty state (which remains for the personal "me" context).
"Ann is building CONTEXT.md for X" is posted as a durable feed message against the backend channel. Requires posthog#70320 server-side; silently no-ops until it deploys.
Server-emitted channel_created/context_created rows are filtered out so nothing duplicates once the backend lands.

Rename — channels are now "contexts" across the UI copy (sidebar, dialogs, menus).

Screenshots from earlier iterations of this PR (create dialog has since dropped the description field; the feed now opens with the intro)

Known follow-ups:

"Learn more about contexts" card needs a destination.
The context.md card doesn't yet reflect an in-flight plan session (a second click can start a duplicate session).

How did you test this?

Manual: created a context in the desktop app; verified the name-only dialog, the intro (name, mention-chip creation line, Today marker, joined row), the create-card → describe dialog → plan session flow, and the task card appearing in the feed.
pnpm --filter @posthog/ui typecheck and Biome clean; lint-staged (biome + typecheck) passed on commit.

Automatic notifications

Publish to changelog?
Alert Sales and Marketing teams?

Reworks the create-context dialog into a plan-mode launcher and gives the context index a real feed of "PostHog agent" system messages. Create dialog (quill Dialog): asks for a name + a description of what the context is about, then launches a cloud plan-mode session that investigates the repo and PostHog and co-builds CONTEXT.md with the user (buildContextGenerationPrompt seeds it with the description). Resolves adapter/model like the composer so cloud runs aren't rejected, and owns the task on the backend channel so it lands in the context feed (not just Recents). On failure the context is kept and the typed description is preserved for the next attempt. Context feed: after launch you land on the context index, where durable, team- visible announcements render alongside the plan task card — "created this context" (server-emitted channel_created) then "is building CONTEXT.md" (context_md_building), in order, then the card you click into for the session. Backed by the new ChannelFeedMessage endpoint (posthog/posthog); ordered via explicit timestamps. Removes the old fire-and-forget generation-task tracking (setGenerationTask / useFolderGenerationTask / GeneratingState + polling); the empty-state "Build with agent" now opens the same describe-and-plan dialog. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

The feed-message endpoint (posthog#70320) isn't deployed, so the feed opened with the plan-task card instead of a creation announcement. Synthesize the opener from TaskChannel.created_at/created_by — canonical, always sorts first, deploy-independent — and filter server-emitted channel_created/context_created rows so nothing duplicates once the backend lands. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

trunk-io · 2026-07-12T22:55:11Z

😎 Merged manually by @adamleithp - details.

greptile-apps · 2026-07-12T22:57:28Z

_{Reviews (1): Last reviewed commit: "fix(canvas): derive 'created this contex..." | Re-trigger Greptile}

adamleithp · 2026-07-12T23:06:13Z

+      // Restore a description stashed by a prior failed launch (create mode
+      // only), otherwise start blank. Consuming clears the stash.
+      setDescription(isDescribeMode ? "" : stashedDescription);
+      stashedDescription = "";


[correctness, CONFIRMED] The stash's only write path is the create-mode launch failure, which navigates to the context home — where the natural retry is the CONTEXT.md empty state's "Build with agent", which reopens this component in describe mode. This open branch then blanks the field (isDescribeMode ? "") and clears stashedDescription without consuming it, so the advertised restore never survives the natural flow. And because the variable is module-global and keyed to nothing, a stash from failed context A can pre-fill a later, unrelated create dialog for context B.

Consider only consuming/clearing the stash in create mode, and keying it (or better: pre-filling the describe-mode dialog with it, since that's where the user actually retries).

adamleithp · 2026-07-12T23:06:35Z

 }

+/** Lifecycle events a channel-feed system message can announce. */
+export type ChannelFeedMessageEvent = "context_created" | "context_md_building";


[simplification, CONFIRMED] context_created is never posted anywhere in this repo (only context_md_building is), and useChannelFeedMessages explicitly filters it out via CREATION_EVENTS. Advertising it in the union invites a developer to post an event that gets silently dropped from the feed. Narrow the union to "context_md_building" until a second event ships.

- Resolve the cloud model via modelResolver.resolveDefaultModel (like the freeform-canvas flow) instead of trusting the composer picker's async state; hard-stop with a toast when no model resolves, before the task (and orphaned context) is created. - Stop polling the channel feed once the query errors and disable retries — the endpoint 404s on prod until posthog#70320 deploys, and the old numeric interval + default retries streamed ~4 requests per 5s forever. - Make the feed merge comparator consistent for equal timestamps. - Only consume the stashed create-dialog description in create mode, so the describe-mode open the failed-launch flow lands on doesn't wipe it. - Narrow ChannelFeedMessageEvent to the one event actually posted. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

# Conflicts: # packages/ui/src/features/canvas/components/CreateChannelModal.tsx # packages/ui/src/features/canvas/hooks/useGenerateContext.ts

The intro card flips to a tone=success 'Created context.md' state once instructions exist instead of disappearing, and gains a learn-more placeholder card. TaskCard title drops the Radix Text wrapper for a plain span. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

adamleithp · 2026-07-14T13:26:36Z

/trunk merge

github-actions · 2026-07-14T13:26:48Z

React Doctor found 3 issues in 2 files · 3 warnings.

3 warnings

src/features/canvas/components/ChannelIntro.tsx

⚠️ src/features/canvas/components/ChannelIntro.tsx:100 Control missing accessible label control-has-associated-label
⚠️ src/features/canvas/components/ChannelIntro.tsx:122 Control missing accessible label control-has-associated-label

src/features/canvas/components/WebsiteChannelHome.tsx

⚠️ src/features/canvas/components/WebsiteChannelHome.tsx:236 JSX element passed as a prop jsx-no-jsx-as-prop

_{Reviewed by React Doctor for commit 7d0387d.}

… day-diff The intro card gains a building state detected from the channel's plan task (by title prefix — the only task/context.md tie until the backend links them) and stays inert while the instructions query loads. The create dialog gets an off-by-default toggle that reveals the context.md textarea and launches the plan session at creation; plan-launching submits are labeled 'Plan and create'. The triplicated local-day-diff math collapses into getLocalDayDiff in @posthog/shared. Quill is bumped to 0.3.0-beta.23 — the lockfile still pinned beta.22, whose Item lacks the tone prop, which is what failed CI typecheck in apps/web. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

adamleithp · 2026-07-14T13:41:39Z

/trunk merge

The Field wrapper stretched the Switch to fill the row, pushing its label off-screen. Use a plain associated label with a shrink-0 Switch. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

adamleithp · 2026-07-14T13:56:30Z

/trunk merge

…sName Move the create dialog's flex layout onto the scrolling viewport via the new DialogBody viewportClassName prop instead of the outer wrapper. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

adamleithp · 2026-07-14T14:12:34Z

/trunk merge

- Pass the gateway-resolved model to createTask instead of discarding it for the hardcoded default the resolver was added to replace. - Poll folder instructions while empty (5s, stops once content exists) so an agent's mid-run CONTEXT.md publish flips the intro card to "created" and replaces the CONTEXT.md tab's empty state without a manual reload. - Break feed-sort timestamp ties system-row-first so the "building CONTEXT.md" announcement stays above its task card if the backend truncates the 1ms offset. - Deduplicate the personal-vs-public channel resolution into a shared resolveBackendChannelId exported from useTaskChannels. - Cover getLocalDayDiff with unit tests. Generated-By: PostHog Code Task-Id: 0d69fc27-3c1d-480c-8979-8b9821c90ff9

raquelmsmith

I've throughly reviewed and found nothing that needed addressing

adamleithp and others added 3 commits July 12, 2026 13:02

Rename channels to contexts

acc71f6

greptile-apps Bot reviewed Jul 12, 2026

View reviewed changes

Comment thread packages/ui/src/features/canvas/components/CreateChannelModal.tsx

Comment thread packages/ui/src/features/canvas/hooks/useGenerateContext.ts

Comment thread packages/ui/src/features/canvas/components/ChannelFeedView.tsx Outdated