High Risk →

app_start

Launch an app on the device. Uses scrcpy START_APP when a session is active for faster launch, falls back to ADB `am start`. Supports force-stop prefix (+) to stop the app before launching.

Part of the Scrcpy MCP server. Enforce policies on this tool with Intercept, the open-source MCP proxy.

scrcpy-mcp Execute Risk 3/5

AI agents invoke app_start to trigger processes or run actions in Scrcpy. Execute operations can have side effects beyond the immediate call -- triggering builds, sending notifications, or starting workflows. Rate limits and argument validation are essential to prevent runaway execution.

app_start can trigger processes with real-world consequences. An uncontrolled agent might start dozens of builds, send mass notifications, or kick off expensive compute jobs. Intercept enforces rate limits and validates arguments to keep execution within safe bounds.

Execute tools trigger processes. Rate-limit and validate arguments to prevent unintended side effects.

io-github-juancf-scrcpy-mcp.yaml
tools:
  app_start:
    rules:
      - action: allow
        rate_limit:
          max: 10
          window: 60
        validate:
          required_args: true

See the full Scrcpy policy for all 38 tools.

Tool Name app_start
Category Execute
MCP Server Scrcpy MCP Server
Risk Level High

View all 38 tools →

Agents calling execute-class tools like app_start have been implicated in these attack patterns. Read the full case and prevention policy for each:

Browse the full MCP Attack Database →

Other tools in the Execute risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.

app_start is one of the high-risk operations in Scrcpy. For the full severity-focused view — only the high-risk tools with their recommended policies — see the breakdown for this server, or browse all high-risk tools across every MCP server.

What does the app_start tool do? +

Launch an app on the device. Uses scrcpy START_APP when a session is active for faster launch, falls back to ADB `am start`. Supports force-stop prefix (+) to stop the app before launching.. It is categorised as a Execute tool in the Scrcpy MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on app_start? +

Add a rule in your Intercept YAML policy under the tools section for app_start. You can allow, deny, rate-limit, or validate arguments. Then run Intercept as a proxy in front of the Scrcpy MCP server.

What risk level is app_start? +

app_start is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit app_start? +

Yes. Add a rate_limit block to the app_start rule in your Intercept 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 app_start completely? +

Set action: deny in the Intercept policy for app_start. 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 app_start? +

app_start is provided by the Scrcpy MCP server (scrcpy-mcp). Intercept sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policies on Scrcpy

Open source. One binary. Zero dependencies.

npx -y @policylayer/intercept
github.com/policylayer/intercept →
// GET IN TOUCH

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