computer_open_app
Open (or bring to front) an application by name, e.g.
This record as markdown: /tools/yuga-hashimoto-localant/computer-open-app.md
What computer_open_app does on LocalAnt
AI agents invoke computer_open_app to trigger actions in LocalAnt. 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.
Why computer_open_app is rated High
Opening an application is an execution action: it runs a program on the host machine. While it doesn't directly delete data or move money, launching arbitrary applications can have wide-ranging side effects depending on which app is opened. Severity is medium because the action is bounded to opening/foregrounding apps rather than arbitrary shell execution, but misuse (e.g., opening a malicious app) could cause harm.
From the tool's definition 'Open (or bring to front) an application by name' — launches or foregrounds a local application on the PC
Attacks that exploit this kind of access
The rule that runs computer_open_app safely
PolicyLayer is an MCP gateway: it sits between your AI agents and LocalAnt, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For computer_open_app, this is the rule to start with:
computer_open_app 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.
The button opens the PolicyLayer dashboard: create your workspace, connect LocalAnt, apply this rule, and every computer_open_app call is checked against it from then on.
Questions about computer_open_app
Open (or bring to front) an application by name, e.g. It is categorised as a Execute tool in the LocalAnt MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.
Register the LocalAnt MCP server in PolicyLayer and add a rule for computer_open_app: 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 LocalAnt. Nothing to install.
computer_open_app 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 computer_open_app 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 computer_open_app. 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.
computer_open_app is provided by the LocalAnt MCP server (yuga-hashimoto/localant). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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