Create a new project and connect this workspace to it. Pass 'brief_text' (product brief as text) to auto-extract ICPs, pain points, and value props as inferred entities (costs 5 credits). Or pass 'brief_path' (absolute file path) and the file will be read locally. Without a brief, the project is ...
Part of the Cantrip server.
Free to start. No card required.
AI agents use cantrip_init to create or modify resources in Cantrip. 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 cantrip_init 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 Cantrip.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"cantrip_init": {
"limits": [
{
"counter": "cantrip_init_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Cantrip policy for all 19 tools.
These attack patterns abuse exactly the kind of access cantrip_init 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.
Create a new project and connect this workspace to it. Pass 'brief_text' (product brief as text) to auto-extract ICPs, pain points, and value props as inferred entities (costs 5 credits). Or pass 'brief_path' (absolute file path) and the file will be read locally. Without a brief, the project is created empty (free) and you add entities manually. Writes .cantrip.json automatically after creation. After creating a project, add a few entities and confirm them with the user before going deeper.. It is categorised as a Write tool in the Cantrip MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Cantrip MCP server in PolicyLayer and add a rule for cantrip_init: 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 Cantrip. Nothing to install.
cantrip_init 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 cantrip_init 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 cantrip_init. 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.
cantrip_init is provided by the Cantrip MCP server (mcp-server-cantrip). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 19 Cantrip 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.