AI agents invoke type_text to trigger actions in Computer Use. 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.
Typing text into a computer is an active interaction that can trigger commands, form submissions, credential entry, or other operations depending on context. It is a browser/desktop action with effects determined by arguments and target application state.
From the tool's definition 'Type the specified text into the virtual computer' — injects arbitrary keystrokes/text into a running computer environment, triggering whatever input-driven actions the target application responds to.
Documented attack patterns abuse exactly the kind of access type_text gives an agent:
PolicyLayer is an MCP gateway — it sits between your AI agents and Computer Use, and nothing reaches the server without passing your rules. This is the rule we recommend for type_text:
{
"version": "1",
"default": "deny",
"tools": {
"type_text": {
"limits": [
{
"counter": "type_text_rate",
"window": "minute",
"max": 10,
"scope": "grant"
}
]
}
}
}type_text 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.
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Type the specified text into the virtual computer. It is categorised as a Execute tool in the Computer Use MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the Computer Use MCP server in PolicyLayer and add a rule for type_text: 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 Computer Use. Nothing to install.
type_text is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
Yes. Add a rate_limit block to the type_text 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 type_text. 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.
type_text is provided by the Computer Use MCP server (spencerkinney/computer-use-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
Start from Computer Use, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.
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15 Computer Use tools catalogued and risk-classified — across an index of 43,000+ MCP servers.