This record as markdown: /tools/cowork-os/canvas-snapshot.md
What canvas_snapshot does on CoWork OS
AI agents call canvas_snapshot to retrieve information from CoWork OS without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
Why canvas_snapshot is rated Low
canvas_snapshot retrieves/captures the current state of canvas content via screenshot. It has no side effects, does not modify data, does not execute code or commands, and does not delete or move resources. This is a straightforward read operation with minimal risk—the only output is visual data of existing content.
From the tool's definition Tool description: 'Take a screenshot of the canvas content.' This is a retrieval operation that captures visual state without modifying, deleting, or executing external operations.
Attacks that exploit this kind of access
The rule that runs canvas_snapshot safely
PolicyLayer is an MCP gateway: it sits between your AI agents and CoWork OS, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For canvas_snapshot, this is the rule to start with:
canvas_snapshot 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 CoWork OS, apply this rule, and every canvas_snapshot call is checked against it from then on.
Questions about canvas_snapshot
Take a screenshot of the canvas content. It is categorised as a Read tool in the CoWork OS MCP Server, which means it retrieves data without modifying state.
Register the CoWork OS MCP server in PolicyLayer and add a rule for canvas_snapshot: 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 CoWork OS. Nothing to install.
canvas_snapshot 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_snapshot 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_snapshot. 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_snapshot is provided by the CoWork OS MCP server (CoWork-OS/CoWork-OS). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
More on CoWork OS, and thousands of servers like it.
This server
Across the catalogue