block_add_exceptions · AF_ MCP: Risk & Policy

WHAT IT DOES

What block_add_exceptions does on AF_MCP

AI agents use block_add_exceptions to create or update resources in AF_MCP — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your AF_MCP environment.

WHY IT NEEDS A POLICY

Why block_add_exceptions needs a policy

This tool creates/adds new exception configurations to blocking rules, fitting the Write category (creates/modifies data reversibly). Severity is high because misuse could inadvertently whitelist malicious IPs or create security gaps by adding broad exceptions to blocking policies.

From the tool's definition Tool name contains 'add' and description translates to 'bulk add exception blocking configuration.' This creates or modifies exception rules in the security device's blocking configuration, which are reversible changes.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

block_add_exceptions Rate-limited

block_add_exceptions 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.

View as policy code

policy.json

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

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches AF_MCP, so you can run agents against it safely.

FAQ

Questions about block_add_exceptions

What does the block_add_exceptions tool do? +

批量新增例外封锁配置。. It is categorised as a Write tool in the AF_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 block_add_exceptions? +

Register the AF_ MCP server in PolicyLayer and add a rule for block_add_exceptions: 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 AF_MCP. Nothing to install.

What risk level is block_add_exceptions? +

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

Can I rate-limit block_add_exceptions? +

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

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

block_add_exceptions is provided by the AF_ MCP server (xiaqijun/af_mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.