canvas_view
查询或操作当前会话前台画布：选择、聚焦、适应画布、视口、选择/拖动工具、工作台展开及大小位置。query允许计划模式，其余操作需要执行权限；没有对应前台画布时明确不可用，不改变其他会话。
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What canvas_view does on DutyDeck
AI agents call canvas_view to retrieve information from DutyDeck without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why canvas_view is rated Low
Even though canvas_view only reads data, uncontrolled read access leaks sensitive information and racks up API costs: an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Attacks that exploit this kind of access
The rule that runs canvas_view safely
PolicyLayer is an MCP gateway: it sits between your AI agents and DutyDeck, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For canvas_view, this is the rule to start with:
canvas_view is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.
The button opens the PolicyLayer dashboard: create your workspace, connect DutyDeck, apply this rule, and every canvas_view call is checked against it from then on.
Questions about canvas_view
查询或操作当前会话前台画布：选择、聚焦、适应画布、视口、选择/拖动工具、工作台展开及大小位置。query允许计划模式，其余操作需要执行权限；没有对应前台画布时明确不可用，不改变其他会话。. It is categorised as a Read tool in the DutyDeck MCP Server, which means it retrieves data without modifying state.
Register the DutyDeck MCP server in PolicyLayer and add a rule for canvas_view: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches DutyDeck. Nothing to install.
canvas_view is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the canvas_view rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.
Set action: deny in the PolicyLayer policy for canvas_view. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.
canvas_view is provided by the DutyDeck MCP server (taokoplay/DutyDeck). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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