Create graph from Mermaid flowchart. Edge labels become relation types.
AI agents use create_from_mermaid to create or update resources in Mcp Graph Engine — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Graph Engine environment.
This tool creates a new graph from a Mermaid diagram specification. While it initializes data structures in the graph database, the creation is reversible (the graph can be deleted via delete_graph or overwritten). This places it in the Write category rather than Destructive.
From the tool's definition Tool name 'create_from_mermaid' and description 'Create graph from Mermaid flowchart' indicate the tool creates new graph structures. Edge labels become relation types, confirming data creation/initialization rather than modification of existing data.
Documented attack patterns abuse exactly the kind of access create_from_mermaid gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Graph Engine, and nothing reaches the server without passing your rules. This is the rule we recommend for create_from_mermaid:
{
"version": "1",
"default": "deny",
"tools": {
"create_from_mermaid": {
"limits": [
{
"counter": "create_from_mermaid_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}create_from_mermaid 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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Create graph from Mermaid flowchart. Edge labels become relation types. It is categorised as a Write tool in the Mcp Graph Engine MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mcp Graph Engine MCP server in PolicyLayer and add a rule for create_from_mermaid: 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 Mcp Graph Engine. Nothing to install.
create_from_mermaid 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 create_from_mermaid 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 create_from_mermaid. 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.
create_from_mermaid is provided by the Mcp Graph Engine MCP server (utilitydelta/mcp-graph-engine). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mcp Graph Engine, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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24 Mcp Graph Engine tools catalogued and risk-classified — across an index of 43,000+ MCP servers.