Use this to change the VoIP pricing plan assigned to a specific subscriber. VoIP plans control billing rates for VoIP calls made through the OCS platform, separate from the standard mobile plan's call rates. Params: iccid (subscriber identifier), voip_plan_id (integer VoIP plan ID from the OCS re...
Part of the Carrier MCP: Give Your AI Agent Global Connectivity server.
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AI agents use modify_subscriber_voip_plan to create or modify resources in Carrier MCP: Give Your AI Agent Global Connectivity. 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 modify_subscriber_voip_plan 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 Carrier MCP: Give Your AI Agent Global Connectivity.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"modify_subscriber_voip_plan": {
"limits": [
{
"counter": "modify_subscriber_voip_plan_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full Carrier MCP: Give Your AI Agent Global Connectivity policy for all 65 tools.
These attack patterns abuse exactly the kind of access modify_subscriber_voip_plan gives an agent. Each links to the full case and the policy that stops it:
Other write tools across the catalogue. The same approach applies to each: rate-limit and validate the arguments.
Use this to change the VoIP pricing plan assigned to a specific subscriber. VoIP plans control billing rates for VoIP calls made through the OCS platform, separate from the standard mobile plan's call rates. Params: iccid (subscriber identifier), voip_plan_id (integer VoIP plan ID from the OCS reseller settings). Returns: updated subscriber record confirming the new VoIP plan. Do NOT use this for mobile (non-VoIP) plan changes — use modify_subscriber_mobile_plan. For data-only eSIM products without VoIP services this tool has no effect.. It is categorised as a Write tool in the Carrier MCP: Give Your AI Agent Global Connectivity MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Carrier MCP: Give Your AI Agent Global Connectivity MCP server in PolicyLayer and add a rule for modify_subscriber_voip_plan: 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 Carrier MCP: Give Your AI Agent Global Connectivity. Nothing to install.
modify_subscriber_voip_plan 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 modify_subscriber_voip_plan 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 modify_subscriber_voip_plan. 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.
modify_subscriber_voip_plan is provided by the Carrier MCP: Give Your AI Agent Global Connectivity MCP server (carrier/mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 65 Carrier MCP: Give Your AI Agent Global Connectivity tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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