Push a BlackBox command directly to a paired SDK device (or broadcast to all) without needing an active dev-server. This is the Path-C/8 fallback for the cross-device reload workflow: Phone A drives, Phone B receives, no Metro bundler involved — both phones just share a Yaver agent (managed-cloud...
AI agents call device_broadcast_command to retrieve information from Yaver without modifying anything — typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.
| Parameter | Type | Required | Description |
|---|---|---|---|
data | object | — | Optional command payload passed through verbatim to the SDK listener. |
command | string | Yes | BlackBox command name — what the SDK listener acts on (e.g. "reload", "reload_bundle", "open_app"). |
target_device_id | string | — | When set, scoped to that one SDK session. Empty/omitted = broadcast to all subscribed devices. |
Parameters from the server's own tool schema.
Even though device_broadcast_command only reads data, uncontrolled read access leaks sensitive information and racks up API costs — an agent caught in a retry loop can make thousands of calls a minute without anyone noticing.
Risk signalsAccepts freeform code/query input (command)
Attacks that exploit this kind of access
Push a BlackBox command directly to a paired SDK device (or broadcast to all) without needing an active dev-server. This is the Path-C/8 fallback for the cross-device reload workflow: Phone A drives, Phone B receives, no Metro bundler involved — both phones just share a Yaver agent (managed-cloud, self-hosted, or local). Examples of useful commands: "reload", "reload_bundle", "open_app". Returns { ok, mode: "scoped"|"broadcast"|"no_blackbox", targetDeviceId?, reachedSession? }. It is categorised as a Read tool in the Yaver MCP Server, which means it retrieves data without modifying state.
device_broadcast_command accepts 3 parameters: data, command, target_device_id. Required: command. The full parameter table on this page comes from the server's own tool schema.
Register the Yaver MCP server in PolicyLayer and add a rule for device_broadcast_command: 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 Yaver. Nothing to install.
device_broadcast_command is a Read tool with low risk. Read-only tools are generally safe to allow by default.
Yes. Add a rate_limit block to the device_broadcast_command 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 device_broadcast_command. 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.
device_broadcast_command is provided by the Yaver MCP server (yaver-cli). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.