mess_uncancel_registration

THE RISK

Medium Risk

Why mess_uncancel_registration needs a policy

This tool reverses a cancellation by restoring a meal registration — a reversible write operation. It modifies existing data (meal registration status) but does not delete or execute anything irreversible. Misuse could result in unintended meal charges, hence medium severity.

From the tool's definition Restore a previously cancelled meal registration

Documented attack patterns abuse exactly the kind of access mess_uncancel_registration gives an agent:

POLICY

How to control mess_uncancel_registration

PolicyLayer is an MCP gateway — it sits between your AI agents and IIITH Mess MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for mess_uncancel_registration:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "mess_uncancel_registration": {
      "limits": [
        {
          "counter": "mess_uncancel_registration_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

mess_uncancel_registration 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.

Create a free account and register IIITH Mess MCP — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

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EXPLORE

Related tools and policies

More IIITH Mess MCP tools

Destructive mess_cancel_registration mess_cancel_registration Destructive mess_delete_auth_key Delete an auth key by its name (not its value). Identified by name in the URL path. Destructive mess_delete_extra_registration Delete an extra registration by its ID (passed as query param). Destructive mess_delete_monthly_registration Delete a monthly mess registration (individual meal registrations are kept). Execute mess_login_msit Login as an MSIT student or intern using email + password. Write mess_reset_qr_token Reset the user's QR code token (shown at the mess counter). Write mess_provide_feedback Submit anonymous feedback for a meal. User must have availed the meal. Write mess_skip_meal Mark a registration as skipped or unskipped.

All 45 IIITH Mess MCP tools →

Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about mess_uncancel_registration

What does the mess_uncancel_registration tool do? +

Restore a previously cancelled meal registration. It is categorised as a Write tool in the IIITH Mess MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on mess_uncancel_registration? +

Register the IIITH Mess MCP server in PolicyLayer and add a rule for mess_uncancel_registration: 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 IIITH Mess MCP. Nothing to install.

What risk level is mess_uncancel_registration? +

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

Can I rate-limit mess_uncancel_registration? +

Yes. Add a rate_limit block to the mess_uncancel_registration 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 mess_uncancel_registration completely? +

Set action: deny in the PolicyLayer policy for mess_uncancel_registration. 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 mess_uncancel_registration? +

mess_uncancel_registration is provided by the IIITH Mess MCP server (kallind/iiith-mess-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every IIITH Mess MCP tool call.

Start from IIITH Mess MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →