Sends a control character to the active iTerm terminal (e.g., Control-C)
Part of the iTerm MCP server.
Free to start. No card required.
AI agents use send_control_character to create or modify resources in iTerm MCP. 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 send_control_character 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 iTerm MCP.
Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.
{
"version": "1",
"default": "deny",
"tools": {
"send_control_character": {
"limits": [
{
"counter": "send_control_character_rate",
"window": "minute",
"max": 30,
"scope": "grant"
}
]
}
}
}See the full iTerm MCP policy for all 3 tools.
These attack patterns abuse exactly the kind of access send_control_character 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.
Sends a control character to the active iTerm terminal (e.g., Control-C). It is categorised as a Write tool in the iTerm MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.
Register the iTerm MCP server in PolicyLayer and add a rule for send_control_character: 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 iTerm MCP. Nothing to install.
send_control_character 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 send_control_character 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 send_control_character. 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.
send_control_character is provided by the iTerm MCP server (lite/iterm-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Deterministic rules across all 3 iTerm MCP tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.
Free to start. No card required.
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