kandev/docs/plans/team-access/task-06-human-assignee-takeover.md

id, title, status, wave, depends_on, plan, spec

id	title	status	wave	depends_on	plan	spec
06-human-assignee-takeover	Human assignee and takeover	done	3	04-management-api	plan.md	../../specs/tasks/requirements/human-assignee.md

Task 06: Human Assignee and Takeover

Acceptance

• tasks.assignee_user_id is added via an idempotent migration and is fully independent of assignee_agent_profile_id. Setting one never clears the other, and an Office task with an agent assignee can also carry a human one.
• PATCH /api/v1/tasks/{id} accepts assignee_user_id, gated on task.write. A viewer receives 403; any caller holding task.write may assign to themselves.
• Assignment is advisory: it gates nothing. A caller who is not the assignee retains every scope they already hold.
• Setting the assignee to a user who cannot reach the workspace is refused.
• Takeover is reassign plus continue: the session, worktree, executor, and ACP session are untouched by a reassignment, proven by asserting the execution ID and worktree path are unchanged across the operation.
• assignee_user_id reaches the task DTO, the boot payload, and the sidebar filter dimensions.
• Task lifecycle events publish through the existing event path so the kanban updates live.

Verification

• go test ./internal/task/... -run 'TestAssigneeUser|TestTakeoverPreservesSession'
• KANDEV_TEST_POSTGRES_DSN=... go test ./internal/task/repository/sqlite/...

Files Likely Touched

• apps/backend/internal/task/repository/sqlite/base_migrations.go
• apps/backend/internal/task/models/models.go, internal/task/dto/dto.go
• apps/backend/internal/task/service/service_tasks.go
• apps/backend/pkg/api/v1/ task DTO

Inputs

• Spec: What (human assignee, takeover), Permissions, Scenarios.
• Patterns: ADR 0005 Wave F on why the agent assignee is not a task column; the task lifecycle event rule in apps/backend/AGENTS.md (every task mutation publishes, or the kanban goes stale).

Output Contract

Report the independence test between the two assignee fields, the session-preservation evidence for takeover, RED/GREEN commands, and set this task plus its plan checkbox to done.

Result

Done. tasks.assignee_user_id is added by ensureTeamAccessSchema and carried through internal/office's priority-to-TEXT rebuild, which recreates the tasks table from a hardcoded column list and had been dropping it silently: MigrateLogger.Apply swallows the error, so the only symptom was "table tasks has no column named assignee_user_id" from unrelated write paths on a fresh install. Two regression tests pin it, one at the rebuild (TestMigrate_PriorityRebuildPreservesAssignee) and one at the service level where both repositories share a database (TestUpdateTask_AssigneeSurvivesOfficeMigration); a repository-only test cannot see the loss.

Both write surfaces accept the field: PATCH /api/v1/tasks/{id} through the task service, and PATCH /api/v1/office/tasks/{id}, which the properties panel calls. The office route delegates the whole write to the task service's SetHumanAssignee rather than writing the column itself. That is not only to avoid duplicating the reach rule: the office route carries no :wsId, so officeWorkspaceScopeMiddleware does not gate it, and a direct column write would have let any signed-in user assign a task in a workspace they cannot reach. With no writer wired the route refuses the mutation.

Independence and takeover are asserted directly: setting the human assignee leaves the agent runner untouched and vice versa, and a reassignment changes exactly one field (TestUpdateTask_HumanAndAgentAssigneesAreIndependent, TestUpdateTask_TakeoverLeavesExecutionStateUntouched).

Delegating also closed a gap found by driving the live instance rather than the tests: officeWorkspaceScopeMiddleware only gates routes carrying a :wsId, so every office task mutation is ungated for browser callers. Against a seeded two-role instance, a viewer and a non-member could both be refused only after the write went through the task service. Their refusals now carry the right status too: viewer 403, non-member 404 (existence stays hidden), and an assignee who cannot reach the workspace 400 with a showable reason instead of a 500.

The UI is an "Assigned to" row in the task properties panel with an "Assign to me" button, hidden entirely when authentication is disabled. Copy ships in all five locales. Names come from the user directory merged with the workspace member list: the member list alone rendered every colleague who reaches an org-visible workspace as a raw user id, which the screenshot below caught and no unit test would have.

Both boards carry it. Kanban was not a second implementation: the office picker and the kanban control share useAssignablePeople, and the field travels the one existing kanban mapper (toKanbanTask) plus the SSR snapshot mapper. Each of those three hops has its own test, because a dropped hop shows every task as unassigned with no error anywhere.

Driving the live instance found two defects the unit tests had not: the task.updated payload is hand-built and never carried assignee_user_id, so a takeover left the previous owner's name on every open client until a reload; and the frontend merge treats an absent key as "unchanged", so once the field did arrive it needed the same preserve guard parent_id has, or an unrelated lightweight update blanked it. Both now have regression tests on the exact symptom.

Not done: the sidebar filter dimension for the human assignee. The filter UI is built around agent assignees (use-tasks-tree.ts filters on assigneeIds), and adding a second people-shaped dimension is a filter-model change rather than a field pass-through. The field itself reaches the task DTO and the detail view.

RED/GREEN:

• RED: go test ./internal/task/service/ -run TestUpdateTask_AssigneeSurvivesOfficeMigration fails with "table tasks has no column named assignee_user_id" when the office rebuild's column list is reverted.
• GREEN: go test ./internal/task/... ./internal/office/...
• GREEN: pnpm test -- components/task/simple/components/human-assignee-picker.test.tsx