Bias subsequent Sparkle guidance toward a persona (student | parent | tutor | explorer). Session-scoped: the host should pass the chosen persona back to get_sparkle_guidance.
Part of the Vocab Voyage server.
Free to start. No card required.
AI agents use set_persona to create or modify resources in Vocab Voyage. Write operations carry medium risk because an autonomous agent could trigger bulk unintended modifications. Rate limits prevent a single agent session from making hundreds of changes in rapid succession. Argument validation ensures the agent passes expected values.
Without a policy, an AI agent could call set_persona repeatedly, creating or modifying resources faster than any human could review. PolicyLayer's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Vocab Voyage.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"set_persona": {
"limits": [
{
"counter": "set_persona_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Vocab Voyage policy for all 31 tools.
These attack patterns abuse exactly the kind of access set_persona gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Bias subsequent Sparkle guidance toward a persona (student | parent | tutor | explorer). Session-scoped: the host should pass the chosen persona back to get_sparkle_guidance.. It is categorised as a Write tool in the Vocab Voyage MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Vocab Voyage MCP server in PolicyLayer and add a rule for set_persona: 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 Vocab Voyage. Nothing to install.
set_persona 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 set_persona 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 set_persona. 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.
set_persona is provided by the Vocab Voyage MCP server (https://gponcrussdahcdyrlhcr.supabase.co/functions/v1/mcp-server?ref=mcp_registry). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 31 Vocab Voyage tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
4,600+ MCP servers and 31,000+ tools scanned and risk-classified.