Medium Risk

key_event

Send a key event to the device. Supports keycodes like HOME, BACK, ENTER, VOLUME_UP, etc.

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

scrcpy-mcp Write Risk 2/5

AI agents use key_event to create or modify resources in Scrcpy. 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 key_event repeatedly, creating or modifying resources faster than any human could review. Intercept's rate limiting ensures write operations happen at a controlled pace, and argument validation catches malformed or unexpected inputs before they reach Scrcpy.

Write tools can modify data. A rate limit prevents runaway bulk operations from AI agents.

io-github-juancf-scrcpy-mcp.yaml
tools:
  key_event:
    rules:
      - action: allow
        rate_limit:
          max: 30
          window: 60

See the full Scrcpy policy for all 38 tools.

Tool Name key_event
Category Write
MCP Server Scrcpy MCP Server
Risk Level Medium

View all 38 tools →

Agents calling write-class tools like key_event 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 Write risk category across the catalogue. The same policy patterns (rate-limit, validate) apply to each.

What does the key_event tool do? +

Send a key event to the device. Supports keycodes like HOME, BACK, ENTER, VOLUME_UP, etc.. It is categorised as a Write tool in the Scrcpy MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on key_event? +

Add a rule in your Intercept YAML policy under the tools section for key_event. 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 key_event? +

key_event is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit key_event? +

Yes. Add a rate_limit block to the key_event 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 key_event completely? +

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

key_event 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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