canvas_task
执行前 start 登记交付；跨回合先 status 查看并 resume 原 taskId。created 是新节点，updated 是原节点新产物。读取真实证据后 complete；证据类提交只能是 {id,evidenceId}，文本 response 只能是 {id,text}，两者不能同时出现。recover 复验原要求，rebind 只允许关联 Host 记录的新建操作。缺少必要输入/能力用 block。不能降低要求、重置预算或拿报告代替成片。
This record as markdown: /tools/dutydeck/canvas-task.md
What canvas_task does on DutyDeck
AI agents invoke canvas_task to trigger actions in DutyDeck. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call: builds kicked off, notifications sent, workflows started.
Why canvas_task is rated High
canvas_task triggers real processes with real consequences. An agent gone sideways doesn't fire it once. It starts dozens of builds, sends mass notifications, or burns through compute before anyone looks up.
Attacks that exploit this kind of access
The rule that runs canvas_task 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_task, this is the rule to start with:
canvas_task stays usable, but rate-capped: a runaway agent can't fire it dozens of times a minute. 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_task call is checked against it from then on.
Questions about canvas_task
执行前 start 登记交付；跨回合先 status 查看并 resume 原 taskId。created 是新节点，updated 是原节点新产物。读取真实证据后 complete；证据类提交只能是 {id,evidenceId}，文本 response 只能是 {id,text}，两者不能同时出现。recover 复验原要求，rebind 只允许关联 Host 记录的新建操作。缺少必要输入/能力用 block。不能降低要求、重置预算或拿报告代替成片。. It is categorised as a Execute tool in the DutyDeck MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the DutyDeck MCP server in PolicyLayer and add a rule for canvas_task: 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_task is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the canvas_task 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_task. 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_task 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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