Board tools

Every agent session gets four tools to see and change the board. Asked to “show me the code that handles login”, an agent opens the file as a frame, at the relevant lines, next to its own frame, instead of pasting code into its reply.

Tool	Does
view_board	Lists the agent’s own cluster row by row, and summarises the others
open_frame	Opens a frame: a file (optionally at a line range), a browser, a terminal, an agent
update_frame	Points a files frame at another file or lines, switches preview/source (markdown, HTML), changes a URL, renames, moves
close_frame	Removes a frame

What an agent can do

An agent has the board powers of a guest with edit access, without approvals. Nothing it does on the board runs anything by itself:

• A terminal frame it opens is an idle shell. The agent cannot type into it.
• An agent frame it opens gets at most a prompt draft. A person sends it.
• A files frame shows only files in the shared set.

Board tool calls therefore never ask for permission. Tool calls that touch the machine, like shell commands, still ask the host.

Placement

Agents name frames and sides (next_to, side), never coordinates. New frames go into the agent’s own cluster, at the end of its row, unless it says otherwise; the layout rules make room. Frames an agent opens are recorded as its own, and it is told to leave other people’s frames alone unless asked.

Priming

canvas tells the agent what the board is, and how to behave on it, through the tool server’s instructions. Agents show these next to their own system prompt, never instead of it, and they never appear in the thread.

Requirements

Board tools work while the host’s browser is open: it runs every call against the board. Without it, the agent is told the board is unavailable. With several host tabs open, the first one connected runs the calls.