Register this session as an agent in the Hive. Returns urn + session_id.
AI agents use hive.agent_register to create or update resources in Mnemos — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mnemos environment.
This tool creates a new record (agent registration) in the Hive system, which is a reversible modification. It does not execute arbitrary code, delete data, or move money. The medium severity reflects that registering an agent could enable subsequent malicious operations if an untrusted agent is registered, but the registration itself is non-destructive and could potentially be revoked or modified.
From the tool's definition Tool description states 'Register this session as an agent in the Hive. Returns urn + session_id.' The verb 'Register' indicates a create/write operation that adds a new agent entry to the system.
Documented attack patterns abuse exactly the kind of access hive.agent_register gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mnemos, and nothing reaches the server without passing your rules. This is the rule we recommend for hive.agent_register:
{
"version": "1",
"default": "deny",
"tools": {
"hive.agent_register": {
"limits": [
{
"counter": "hive.agent_register_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}hive.agent_register 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.
Register this session as an agent in the Hive. Returns urn + session_id. It is categorised as a Write tool in the Mnemos MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mnemos MCP server in PolicyLayer and add a rule for hive.agent_register: 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 Mnemos. Nothing to install.
hive.agent_register 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 hive.agent_register 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 hive.agent_register. 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.
hive.agent_register is provided by the Mnemos MCP server (ncz-os/mnemos). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Mnemos, 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.
15 Mnemos tools catalogued and risk-classified — across an index of 43,000+ MCP servers.