kandev/docs/plans/plugin-backed-canvases/task-06-canvas-lifecycle.md

id, title, status, wave, depends_on, plan, requirements, acceptance_criteria, system_design

id	title	status	wave	depends_on	plan	requirements	acceptance_criteria	system_design
06-canvas-lifecycle	Canvas lifecycle	done	6	05-live-event-transport	plan.md	REQ-CANVASES-AGENT-WEB-APPS-002 REQ-CANVASES-AGENT-WEB-APPS-005 REQ-CANVASES-AGENT-WEB-APPS-007 REQ-CANVASES-AGENT-WEB-APPS-008 REQ-PLUGINS-ISOLATED-WEB-APPS-008 REQ-PLUGINS-ISOLATED-WEB-APPS-010	AC-CANVASES-AGENT-WEB-APPS-002.1 AC-CANVASES-AGENT-WEB-APPS-002.5 AC-CANVASES-AGENT-WEB-APPS-002.6 AC-CANVASES-AGENT-WEB-APPS-005.1 AC-CANVASES-AGENT-WEB-APPS-007.3 AC-CANVASES-AGENT-WEB-APPS-008.1 AC-CANVASES-AGENT-WEB-APPS-008.3 AC-CANVASES-AGENT-WEB-APPS-008.4 AC-PLUGINS-ISOLATED-WEB-APPS-008.1 AC-PLUGINS-ISOLATED-WEB-APPS-008.2 AC-PLUGINS-ISOLATED-WEB-APPS-010.4	../../specs/canvases/system-design/agent-authored-web-apps.md ../../specs/plugins/system-design/isolated-web-app-contributions.md

Task 06: Canvas lifecycle

Summary

Create the plugin-backed canvas model from current main. Add atomic count admission, task cleanup, workspace cleanup, archive, restore, and removal.

In scope

• Add the canvas-to-plugin-instance model, repository, and services.
• Add task and workspace canvas list and get operations.
• Add lifecycle WebSocket events without application content.
• Enforce 10 canvases per task and 100 canvases per workspace.
• Count archived canvases and make restore admission atomic.
• Remove task canvases during task cleanup.
• Remove every canvas during workspace deletion.
• Record durable artifact cleanup before release ownership disappears.
• Add restart, concurrency, cleanup, and unavailable-release tests.

Out of scope

• Declarative canvas cutover, agent publishing, promotion, editing, and host surfaces.

Acceptance

• Canvas scope and active release identity survive backend restart.
• Concurrent create or restore cannot exceed the task or workspace limit.
• Workspace removal leaves no live canvas authority or untracked artifact.

Verification

cd apps/backend && go test ./internal/canvas/... ./internal/gateway/websocket/... ./internal/task/service/... ./internal/backendapp/...

Files likely touched

• apps/backend/internal/canvas/**
• apps/backend/internal/gateway/websocket/canvas_*.go
• apps/backend/internal/backendapp/**
• apps/backend/internal/task/service/**
• plugin artifact cleanup integration

Dependencies

• Tasks 02 through 05 provide plugin instances, releases, runtime state, and event transport.

Risks

• Task cleanup can erase a promoted canvas if scope checks use origin data.
• Workspace deletion can lose artifact cleanup inventory before commit.
• Restore admission can race with create without one transaction boundary.

Parallelism

sequential

Inputs

• Canvas model, state machine, limits, cleanup, API, and failure sections.
• Current task and workspace cleanup transaction patterns.

Results

Implemented the canvas metadata repository and service, atomic task/workspace admission, atomic canvas and plugin-instance lifecycle transactions, archive and restore, task and workspace cleanup, lifecycle event projection, startup orphan reconciliation, and durable artifact-cleanup jobs.

Verification:

• go test ./internal/plugins/instances ./internal/canvas ./internal/backendapp ./internal/plugins/webapp ./internal/mcp/server -count=1 — passed.
• The feature-related packages in go test ./... -count=1 passed. The full repository run still reports the known home-config discovery and launcher restart-fixture failures caused by this VM's /root/.kandev/config.yaml.