feat(sidebar): add last activity task sorting (#2762)

2026-08-18 10:15:42 +01:00
parent 270ddbff8f
commit 704f652f30
74 changed files with 2525 additions and 162 deletions
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+# ADR-2026-08-17-separate-task-activity-from-summary-freshness: Separate Task Activity From Summary Freshness
+
+**Status:** accepted
+**Date:** 2026-08-17
+**Area:** backend, frontend, protocol
+
+## Context
+
+Task sidebar rows currently use `TaskStatusSummary.updated_at` as their visible
+time and saved-view sort value. That field records when any projected status
+changed. A pull-request poll can therefore make many idle tasks look recently
+active even when no user opened them and no agent ran.
+
+Users need both concepts. Projection freshness is useful for status diagnostics,
+while task activity is useful for finding recent work.
+
+## Decision
+
+Kandev will keep `TaskStatusSummary.updated_at` as transport and projection
+freshness. It will add semantic field `last_activity_at` to the same bounded,
+rebuildable summary.
+
+`last_activity_at` is the latest durable time from these sources:
+
+- task creation or a persisted task mutation
+- a user-authored prompt, including a prompt that enters the queue
+- an agent turn start or completion
+
+The timestamp does not advance for task focus, session subscription, Git or
+pull-request polling, queue bookkeeping, status-summary repair, or session
+metadata maintenance. Live projection uses source timestamps and applies a
+monotonic maximum. Rebuilds batch the same durable task, message, and turn
+sources and preserve a newer stored value.
+
+The saved-view wire key is `lastActivityAt`. The existing `updatedAt` key keeps
+its behavior, so stored views remain compatible and users can choose either
+meaning.
+
+This decision extends
+[ADR-2026-08-01-separate-task-summary-session-stream-traffic](2026-08-01-separate-task-summary-session-stream-traffic.md).
+Task-list consumers continue to use the bounded task summary and do not load
+background session streams.
+
+## Consequences
+
+Idle tasks stay stable when background provider status changes. Desktop and
+mobile saved views can sort by meaningful work without opening task sessions.
+
+The backend needs a batched activity query and more bounded projector inputs.
+Turn milestones prevent per-chunk agent output from producing task-list update
+traffic. A running turn becomes recent when it starts and advances again when
+it completes.
+
+Older summaries need a one-time semantic repair. During partial rollout, the
+frontend falls back to the task update or creation time when
+`last_activity_at` is absent.
+
+## Alternatives Considered
+
+- **Reuse summary `updated_at`.** Rejected because provider and Git status
+  changes are not user or agent activity.
+- **Use only `tasks.updated_at`.** Rejected because prompts and agent turns do
+  not always mutate the task row.
+- **Derive activity in each browser.** Rejected because background session
+  history is not loaded and task switchers must not subscribe to it.
+- **Write every activity to the task row.** Rejected because message and turn
+  domains gain extra task writes and mix activity with task edits.
@@ -172,4 +172,5 @@ Read individual ADRs for full context. Create new ones via `/record decision` or
 | 2026-08-12-task-bound-fork-destinations | [Bind Fork Push Destinations to Tasks](2026-08-12-task-bound-fork-destinations.md) | accepted (amended 2026-08-13) | backend, frontend, workflow, security, GitHub | 2026-08-12 |
 | 2026-08-13-hard-delete-task-contribution-links | [Hard delete owns task contribution links](2026-08-13-hard-delete-task-contribution-links.md) | accepted | backend | 2026-08-13 |
 | 2026-08-15-office-mode-follows-active-workspace | [Office Mode Follows the Active Workspace](2026-08-15-office-mode-follows-active-workspace.md) | accepted | frontend, backend | 2026-08-15 |
+| 2026-08-17-separate-task-activity-from-summary-freshness | [Separate Task Activity From Summary Freshness](2026-08-17-separate-task-activity-from-summary-freshness.md) | accepted | backend, frontend, protocol | 2026-08-17 |
 | 2026-08-17-release-pr-ruleset-bypass | [Give Stable Release PRs an Administrator Token Bypass](2026-08-17-release-pr-ruleset-bypass.md) | accepted | infra, workflow, security | 2026-08-17 |