AI agents use closeTunnel to create or update resources in Mcp Ssh — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Mcp Ssh environment.
An AI agent can call closeTunnel faster than any human can review — one bad instruction and it creates or modifies resources in Mcp Ssh by the hundred, each call as confident as the last.
Documented attack patterns abuse exactly the kind of access closeTunnel gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Mcp Ssh, and nothing reaches the server without passing your rules. This is the rule we recommend for closeTunnel:
{
"version": "1",
"default": "deny",
"tools": {
"closeTunnel": {
"limits": [
{
"counter": "closetunnel_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}closeTunnel 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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Closes an active SSH tunnel. It is categorised as a Write tool in the Mcp Ssh MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the Mcp Ssh MCP server in PolicyLayer and add a rule for closeTunnel: 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 Mcp Ssh. Nothing to install.
closeTunnel 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 closeTunnel 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 closeTunnel. 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.
closeTunnel is provided by the Mcp Ssh MCP server (shuakami/mcp-ssh). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 23 Mcp Ssh tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
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23 Mcp Ssh tools catalogued and risk-classified — across an index of 42,500+ MCP servers.