canvas_read

按 ID 读取有限节点、正文与邻接；expectedRevision 固定审核基线。逐节点 readError 表示读取失败，missingNodeIds 表示不存在，omittedEdgeCount 表示相关连线未完整返回，需补读后才能替换节点。complete 仅表示数据完整，不代表审核通过。文档或 WebView 单节点正文仍截断时，使用 canvas_read_version 按 artifact.currentRevision 从 offset=0 跟随 nextOffset 分页；全部送达后取 evidence 完成交付。Agent 配置更新使用顶层 revision 与 a...

SERVERDutyDeck SOURCEtaokoplay/DutyDeck

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/dutydeck/canvas-read.md

WHAT IT DOES

What canvas_read does on DutyDeck

AI agents call canvas_read 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.

RISK

Why canvas_read is rated Low

Even though canvas_read 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

RECOMMENDED RULE

The rule that runs canvas_read 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_read, this is the rule to start with:

canvas_read Allowed

canvas_read is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "canvas_read": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect DutyDeck, apply this rule, and every canvas_read call is checked against it from then on.

FAQ

Questions about canvas_read

What does the canvas_read tool do? +

How do I enforce a policy on canvas_read? +

Register the DutyDeck MCP server in PolicyLayer and add a rule for canvas_read: 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.

What risk level is canvas_read? +

canvas_read is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit canvas_read? +

Yes. Add a rate_limit block to the canvas_read 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.

How do I block canvas_read completely? +

Set action: deny in the PolicyLayer policy for canvas_read. 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.

What MCP server provides canvas_read? +

canvas_read 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.

KEEP EXPLORING

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