Add a user to a Twitter List.
AI agents use add_list_member to create or update resources in Twikit — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Twikit environment.
Adding a list member is a Write operation: it modifies data (list membership) in a reversible manner without executing arbitrary code or deleting data. Severity is medium because misuse could add unwanted users to lists, which could affect privacy or list curation, but the blast radius is limited to list membership changes that can be undone.
From the tool's definition Tool description states 'Add a user to a Twitter List' — this creates/modifies a membership relationship on Twitter, a reversible action.
Documented attack patterns abuse exactly the kind of access add_list_member gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Twikit, and nothing reaches the server without passing your rules. This is the rule we recommend for add_list_member:
{
"version": "1",
"default": "deny",
"tools": {
"add_list_member": {
"limits": [
{
"counter": "add_list_member_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}add_list_member 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.
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Add a user to a Twitter List. It is categorised as a Write tool in the Twikit MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Twikit MCP server in PolicyLayer and add a rule for add_list_member: 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 Twikit. Nothing to install.
add_list_member 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 add_list_member 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 add_list_member. 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.
add_list_member is provided by the Twikit MCP server (tangivis/twitter-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Twikit, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
Free to start. No card required.
59 Twikit tools catalogued and risk-classified — across an index of 43,000+ MCP servers.