AI agents use add_connection_to_canvas 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 new visual elements (connections/arrows) on a canvas, which is a reversible modification of data structure. It does not delete, execute code, or cause destructive changes. The canvas remains editable and connections can be removed. This fits the Write category (creates or modifies data reversibly) rather than Read (which would be querying connections) or Execute (which would run operations).
From the tool's definition Tool name 'add_connection_to_canvas' and description 'Connect cards with lines/arrows' indicate creation of visual relationship elements within a canvas. This modifies the canvas structure by adding new connection objects.
Documented attack patterns abuse exactly the kind of access add_connection_to_canvas 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_connection_to_canvas:
{
"version": "1",
"default": "deny",
"tools": {
"add_connection_to_canvas": {
"limits": [
{
"counter": "add_connection_to_canvas_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_connection_to_canvas 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.
Free to start. No card required.
Connect cards with lines/arrows. 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_connection_to_canvas: 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_connection_to_canvas 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_connection_to_canvas 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_connection_to_canvas. 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_connection_to_canvas is provided by the Obsidian MCP Server MCP server (kynlos/obsidian-mcp). 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.
120 Obsidian MCP Server tools catalogued and risk-classified — across an index of 43,000+ MCP servers.