Generates a single Mermaid diagram from a specification artifact. Supports 17 diagram types: flowchart, sequence, class, ER, state machine, C4 context, C4 container, C4 component, C4 code, activity, use case, DFD (data flow), deployment, network topology, Gantt, pie chart, and mind map.
AI agents use sdd_generate_diagram to create or update resources in Specky — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Specky environment.
This tool creates diagrams (new data artifacts) but does not execute arbitrary code, delete data, or cause financial impacts. The generated diagrams are reversible—they can be recreated, modified, or discarded without consequence. It operates within a specification generation pipeline and produces visualization outputs. The action is clearly generative/creative (Write category) rather than destructive or executable.
From the tool's definition Tool generates and creates Mermaid diagram outputs from specification artifacts. The verb 'generates' and the description 'Generates a single Mermaid diagram' indicate creation of new structured data/artifacts.
Documented attack patterns abuse exactly the kind of access sdd_generate_diagram gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Specky, and nothing reaches the server without passing your rules. This is the rule we recommend for sdd_generate_diagram:
{
"version": "1",
"default": "deny",
"tools": {
"sdd_generate_diagram": {
"limits": [
{
"counter": "sdd_generate_diagram_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}sdd_generate_diagram 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.
Generates a single Mermaid diagram from a specification artifact. Supports 17 diagram types: flowchart, sequence, class, ER, state machine, C4 context, C4 container, C4 component, C4 code, activity, use case, DFD (data flow), deployment, network topology, Gantt, pie chart, and mind map. It is categorised as a Write tool in the Specky MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Specky MCP server in PolicyLayer and add a rule for sdd_generate_diagram: 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 Specky. Nothing to install.
sdd_generate_diagram 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 sdd_generate_diagram 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 sdd_generate_diagram. 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.
sdd_generate_diagram is provided by the Specky MCP server (paulasilvatech/specky). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Specky, 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.
56 Specky tools catalogued and risk-classified — across an index of 43,000+ MCP servers.