rpc_release_handle · Rpcclient MCP: Risk & Policy

WHAT IT DOES

What rpc_release_handle does on Rpcclient

AI agents invoke rpc_release_handle to trigger actions in Rpcclient. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why rpc_release_handle needs a policy

Releasing a stored object handle is an operational action on the iOS RPC session state — it triggers an external operation (freeing a remote object reference on the iOS RPC server). It is not purely a read, nor a simple write, and while it frees a resource, it is not irreversibly destructive to user data.

From the tool's definition Release one stored object handle

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

rpc_release_handle Rate-limited

rpc_release_handle stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "rpc_release_handle": {
      "limits": [
        {
          "counter": "rpc_release_handle_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about rpc_release_handle

What does the rpc_release_handle tool do? +

Release one stored object handle. It is categorised as a Execute tool in the Rpcclient MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on rpc_release_handle? +

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

What risk level is rpc_release_handle? +

rpc_release_handle is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit rpc_release_handle? +

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

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

rpc_release_handle is provided by the Rpcclient MCP server (appknox/rpcclient-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.