Add a node to canvas (file, text, link, or group)
AI agents use add_canvas_node to create or update resources in Obsidian MCP Server — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Obsidian MCP Server environment.
This tool creates or adds data to a canvas in Obsidian—a write operation that modifies the vault's canvas files. The impact is limited to canvas structure changes and is reversible, so it does not reach Destructive severity. Medium severity accounts for potential disruption to existing canvas layouts if an agent adds many unwanted nodes, but the effect is contained to a single canvas element and can be undone.
From the tool's definition Tool description states 'Add a node to canvas' which creates new canvas elements. The action is reversible (nodes can be removed) and modifies the canvas structure by adding content.
Documented attack patterns abuse exactly the kind of access add_canvas_node gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Obsidian MCP Server, and nothing reaches the server without passing your rules. This is the rule we recommend for add_canvas_node:
{
"version": "1",
"default": "deny",
"tools": {
"add_canvas_node": {
"limits": [
{
"counter": "add_canvas_node_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_canvas_node stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.
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Add a node to canvas (file, text, link, or group). It is categorised as a Write tool in the Obsidian MCP Server MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Obsidian MCP Server MCP server in PolicyLayer and add a rule for add_canvas_node: 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 Obsidian MCP Server. Nothing to install.
add_canvas_node is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the add_canvas_node 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 add_canvas_node. 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.
add_canvas_node is provided by the Obsidian MCP Server MCP server (bazylhorsey/obsidian-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Obsidian MCP Server, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
29 Obsidian MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.