Prototype: set a top-level frame as a prototype flow starting point on the current page, or clear it. Flow starting points are page-level — Figma stores them as { nodeId, name } entries on the page.
AI agents use figma_set_flow_starting_point to create or update resources in Figma MCP Bridge — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Figma MCP Bridge environment.
This tool modifies page-level prototype configuration by setting or clearing flow starting points. This is a reversible state change (the clearing operation can undo a setting), so it qualifies as Write rather than Destructive. While it affects design workflow configuration, the blast radius is limited to prototype flow metadata on a single page.
From the tool's definition Tool description states it can 'set a top-level frame as a prototype flow starting point' and 'clear it', indicating creation and modification of prototype flow metadata on Figma pages.
Documented attack patterns abuse exactly the kind of access figma_set_flow_starting_point gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Figma MCP Bridge, and nothing reaches the server without passing your rules. This is the rule we recommend for figma_set_flow_starting_point:
{
"version": "1",
"default": "deny",
"tools": {
"figma_set_flow_starting_point": {
"limits": [
{
"counter": "figma_set_flow_starting_point_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}figma_set_flow_starting_point 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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Prototype: set a top-level frame as a prototype flow starting point on the current page, or clear it. Flow starting points are page-level — Figma stores them as { nodeId, name } entries on the page. It is categorised as a Write tool in the Figma MCP Bridge MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Figma MCP Bridge MCP server in PolicyLayer and add a rule for figma_set_flow_starting_point: 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 Figma MCP Bridge. Nothing to install.
figma_set_flow_starting_point 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 figma_set_flow_starting_point 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 figma_set_flow_starting_point. 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.
figma_set_flow_starting_point is provided by the Figma MCP Bridge MCP server (magic-spells/figma-mcp-bridge). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Figma MCP Bridge, 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.
88 Figma MCP Bridge tools catalogued and risk-classified — across an index of 43,000+ MCP servers.