system_activity

Get current foreground activity (Android only)

SERVERClaude Mobile SOURCEalexgladkov/claude-in-mobile

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/alexgladkov-claude-in-mobile/system-activity.md

WHAT IT DOES

What system_activity does on Claude Mobile

AI agents call system_activity to retrieve information from Claude Mobile without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why system_activity is rated Low

This tool queries the current state of an Android device's foreground activity without making any changes to the system or executing code. It is purely informational and poses minimal risk if misused by an AI agent, as the worst outcome would be reading which app is currently active.

From the tool's definition Tool description explicitly states 'Get current foreground activity' with no modification, deletion, or execution capability. Returns state information only.

Risk signalsAdmin/system-level operation

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs system_activity safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Claude Mobile, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For system_activity, this is the rule to start with:

system_activity Allowed

system_activity is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "system_activity": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Claude Mobile, apply this rule, and every system_activity call is checked against it from then on.

FAQ

Questions about system_activity

What does the system_activity tool do? +

Get current foreground activity (Android only). It is categorised as a Read tool in the Claude Mobile MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on system_activity? +

Register the Claude Mobile MCP server in PolicyLayer and add a rule for system_activity: 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 Claude Mobile. Nothing to install.

What risk level is system_activity? +

system_activity is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit system_activity? +

Yes. Add a rate_limit block to the system_activity 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.

How do I block system_activity completely? +

Set action: deny in the PolicyLayer policy for system_activity. 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.

What MCP server provides system_activity? +

system_activity is provided by the Claude Mobile MCP server (alexgladkov/claude-in-mobile). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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