MCP tools

Your agent calls these tools; you rarely call them yourself. Connect first (Connect your agent). The agent opens a board with start_session, then passes the returned id as board to calls on that board. describe_charts needs no board. create_branch returns a different id for edits to the proposal.

Every write goes through the same rules as a person’s edit. A refused write says why, and the first word tells the agent what to do:

Starts with	Meaning	Agent action
`REJECTED`	the write breaks a rule	read the sentence and fix the call
`UNAVAILABLE`	the server is busy or down	wait the stated time, then call again
`UNCONFIRMED`	the write outcome is unknown	call `get_board` before any retry

Session

Tool	What it does
`start_session`	Opens the task’s board (by name, or by a board link you gave it) and returns its id and URL.
`get_board`	Reads the graph, ref metadata, chart summaries and route progress. Large results report omitted content.

Nodes and edges

Tool	What it does
`create_node`	Adds a component: a service, data store, external system, boundary, note or text block.
`update_node`	Changes a node’s label, sublabel, colour, kind or focus.
`move_node`	Moves a node.
`resize_node`	Resizes a node.
`layout_board`	Lays the board out left to right: entry points left, data stores right.
`hide_node`	Hides a node and its edges without deleting them.
`delete_node`	Deletes a node and its edges.
`create_edge`	Connects two nodes, with a label and the source line that proves the link.
`hide_edge`	Hides an edge without deleting it.
`delete_edge`	Deletes an edge.

Charts

Tool	What it does
`describe_charts`	Lists the chart types and the data each one takes.
`create_chart`	Adds a chart node from CSV data, with a note on where the data came from.
`set_chart_data`	Replaces a chart’s data.
`get_chart`	Reads a chart’s type, data and options.

Code refs, notes and threats

Tool	What it does
`add_code_ref`	Checks a node or edge ref against a file capture. Stores code text only with owner consent.
`remove_code_ref`	Removes a code ref.
`add_change_note`	Flags a migration or other risky change on a node, with the code that reads it.
`update_change_note`	Edits a change note.
`remove_change_note`	Removes a change note.
`add_threat`	Marks a node compromised (from a SIEM alert) or vulnerable (from a scanner finding).
`update_threat`	Edits a threat.
`remove_threat`	Removes a threat.

Traffic

Tool	What it does
`start_tap`	Starts a live view of your app’s local traffic on the board, while you run it.
`set_edge_latency`	Sets an edge’s latency and where the number came from: production, local or an estimate.
`play_trace`	Replays one request on the board, span by span; errors show red.

Red crayon review

People create marks in the canvas. Agents claim and answer them through these tools.

Tool	What it does
`watch_marks`	Returns a command for a background listener, using the seat from `start_session`.
`wait_for_marks`	Waits briefly, claims open marks for that seat, and groups them by shared files.
`reply_to_mark`	Answers a claimed mark with `fixed` or `kept`, a reply and the changed-file list.
`list_marks`	Reads sent marks, their states and replies, optionally for one round.

The listener must run in an active coding session. Sending marks does not start an agent. See Review with the red crayon.

Board branches

Tool	What it does
`create_branch`	Copies a board into an editable proposal and returns its own id and URL.
`submit_branch`	Sends the proposal for a person to review. Later graph edits return it to draft.

Agents cannot accept, reject or merge proposals. These are human actions in the canvas. See Board branches.

Walkthroughs and checkpoints

Tool	What it does
`set_node_doc`	Writes a node’s doc: at most two sentences on what it is and why it exists.
`set_selection`	Shows you which nodes the agent is working on.
`plan_route`	Plans the order in which the agent walks you through the change.
`arrive`	Marks the next stop on the route reached, with a checkpoint.
`reroute`	Changes the stops still ahead on the route, with a reason.
`mark_checkpoint`	Records which changed files the board covers. The agent calls it before every commit and before its final answer.

Code refs, checkpoints, change notes and routes need a session board. If a tool requests a capture, run the exact helper command it returns and retry with the upload id. A drawing-only board still supports diagrams and charts.

Snippet storage is off by default. Code metadata and temporary captures still exist. Agents cannot change the owner’s storage setting. See Your data and code consent.

Share links, embeds, workspace membership and consent are human controls. This reference lists the board tools, not dashboard access-management actions.