Declare active project. Format: [prefix]_[name] (e.g.,
AI agents use register_session_context to create or update resources in N2n Nexus — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your N2n Nexus environment.
This tool creates or modifies a session context record for a project. While not destructive (the change is reversible by registering a different context or clearing it), it clearly writes state to the system rather than merely reading.
From the tool's definition Tool name contains 'register' which indicates state modification. Description states 'Declare active project' which implies creating or establishing a new session context entry in the system.
Documented attack patterns abuse exactly the kind of access register_session_context gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and N2n Nexus, and nothing reaches the server without passing your rules. This is the rule we recommend for register_session_context:
{
"version": "1",
"default": "deny",
"tools": {
"register_session_context": {
"limits": [
{
"counter": "register_session_context_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}register_session_context 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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Declare active project. Format: [prefix]_[name] (e.g.,. It is categorised as a Write tool in the N2n Nexus MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the N2n Nexus MCP server in PolicyLayer and add a rule for register_session_context: 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 N2n Nexus. Nothing to install.
register_session_context 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 register_session_context 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 register_session_context. 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.
register_session_context is provided by the N2n Nexus MCP server (n2ns/n2n-nexus). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from N2n Nexus, 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.
22 N2n Nexus tools catalogued and risk-classified — across an index of 43,000+ MCP servers.