Show something to the human on their mcp-screen canvas (a browser tab next to the terminal). Returns the widget id. Widget kinds and their data:

• markdown {markdown}

• text {text} (monospace log/output)

• table {columns: string[], rows: cell[][]} (sortable; row clicks become the widget selection)

• chart {type: "bar"|"line", labels: string[], values: number[], unit?, linkTo?: tableId} (bar clicks become the selection and filter the linked table)

• metric {value, label?, delta?}

• kv {items: {key: value}}

• status-list {items: [{label, status: "ok"|"fail"|"pending"|"unknown", detail?}]}

• livemap {root?, nodes: [{id, label, globs: string[], layer?, description?}], edges: [{from, to, label?}]} (architecture diagram; file edits matching a node's globs light it up live)

Update an existing widget. data is shallow-merged into the current data by default (send only the keys you change, e.g. {edges} on a livemap); pass merge:false to replace it entirely.

Read a widget back, including selection: what the human clicked (table row, chart bar) or what an MCP App reported. For livemaps, unmappedFiles lists edited files no node covers (time to update the map).

List every widget on the canvas with its id, kind, title, live status and current selection.

Remove a widget (and stop its live refresh).

Remove every widget from the canvas (standup cards stay). The human can undo it from the canvas, or you can call clear_canvas with undo:true right after.

Ask the human a visual question: places clickable choice cards on the canvas and BLOCKS until they click one (or the timeout passes). Use it for decisions that are easier to make by looking: layouts, copy options, which bug to fix first. Returns {answered, choice:{id,label}} or {answered:false, reason}.

Post a standup card when you finish a task: what you changed, test results, a short summary and risks. Cards are grouped by worktree and agent on the Standup board.