Medium Risk

register_session

Register this Claude session. Call at session start.

Part of the Meridian server.

register_session can modify Meridian data, with no limits today. PolicyLayer puts allow, deny, and rate-limit rules on every call. Live in minutes.

SECURE MERIDIAN →

Free to start. No card required.

AI agents use register_session to create or modify resources in Meridian. 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 register_session 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 Meridian.

Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.

policy.json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "register_session": {
      "limits": [
        {
          "counter": "register_session_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

See the full Meridian policy for all 42 tools.

Get this rule live on your own Meridian server in minutes. PolicyLayer enforces it on every call, before it runs.

ENFORCE ON MY MERIDIAN →

View all 42 tools →

These attack patterns abuse exactly the kind of access register_session gives an agent. Each links to the full case and the policy that stops it:

Browse the full MCP Attack Database →

Every attack above starts with a tool call. PolicyLayer checks each one against your policy first, so register_session only ever does what you allow.

SECURE MERIDIAN →

Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.

What does the register_session tool do? +

Register this Claude session. Call at session start.. It is categorised as a Write tool in the Meridian MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on register_session? +

Register the Meridian MCP server in PolicyLayer and add a rule for register_session: 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 Meridian. Nothing to install.

What risk level is register_session? +

register_session is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit register_session? +

Yes. Add a rate_limit block to the register_session 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.

How do I block register_session completely? +

Set action: deny in the PolicyLayer policy for register_session. 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.

What MCP server provides register_session? +

register_session is provided by the Meridian MCP server (@meridianmcp/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Meridian tool call.

Deterministic rules across all 42 Meridian 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.

// GET IN TOUCH

Have a question or want to learn more? Send us a message.

Message sent.

We'll get back to you soon.