#Tap

rozenite agent tap connects to a device and prints Rozenite plugin messages as they flow, in both directions, without opening a browser or React Native DevTools.

The full loop for checking that a plugin's native side behaves — Metro, a simulator, the app, a browser running React Native DevTools, the shell, and the panel — is a lot of overhead just to watch a handful of messages when the thing you're testing lives on the device. tap skips the browser half entirely.

#Watch a plugin's traffic

npx rozenite agent tap --session <id> --plugin @acme/sqlite-plugin

← 12:04:31.220  sqlite:list-tables-request   {"requestId":"a1"}
→ 12:04:31.244  sqlite:list-tables-response  {"requestId":"a1","tables":["users","posts"]}

Each line is a direction arrow, a local timestamp, the message type, and the JSON payload:

• ← — received from the device.
• → — sent to the device.

Omit --plugin to watch every plugin's traffic on the session. tap keeps running until you stop it with Ctrl-C, closing the underlying connection cleanly.

#Poke a plugin and watch what comes back

Because the stream is bidirectional, tap doubles as a minimal stand-in for DevTools: send one message from the terminal, then keep watching for whatever comes back.

npx rozenite agent tap --session <id> --plugin @acme/sqlite-plugin --type sqlite:query --payload '{"sql":"select 1"}'

--plugin, --type, and --payload map directly onto the three fields of the message sent to the device (pluginId, type, payload). --payload defaults to {} and is validated as JSON on its own, so a malformed payload is reported against --payload, not against a blended argument. --type requires --plugin, since a message needs to know which plugin it's addressed to.

--plugin also filters the stream — --type does not, since filtering on it would hide the very response your poke is meant to surface.

#Machine-readable output

Pass --json for newline-delimited JSON, one message per line, so another program or agent can consume the stream directly instead of screenshotting a terminal:

npx rozenite agent tap --session <id> --json

{
  "direction": "in",
  "timestamp": 1700000000000,
  "pluginId": "@acme/sqlite-plugin",
  "type": "list-tables-request",
  "payload": { "requestId": "a1" }
}

Each line has this shape:

#Options

• -s, --session <id> — target Agent session ID (required). Create one with npx rozenite agent session create.
• -p, --plugin <id> — filter the stream to this plugin ID; required together with --type.
• -t, --type <name> — send one message of this type before watching. Requires --plugin.
• -a, --payload <json> — JSON payload for the sent message. Defaults to {}.
• --json — newline-delimited JSON output instead of the human-readable format.
• --host <host> / --port <port> — Metro host and port, inherited from rozenite agent, so they go before tap: npx rozenite agent --host 192.168.1.10 --port 8082 tap --session <id> (defaults to 127.0.0.1:8081).

#tap replaces React Native DevTools

A device serves only one debugger connection at a time. tap rides the same connection rozenite agent uses, so starting a tap — like starting an agent session — disconnects React Native DevTools if it's already attached, and a tap keeps that same device from being opened in DevTools while it's running. This matches the point of tap (working entirely from the terminal), but it will surprise you if you don't expect it. Stop the tap (Ctrl-C) to free the connection back up.

#Next steps

• Rozenite for Agents — the wider agent-facing workflow tap is part of.
• Agent SDK — build custom tooling on top of the same session tap uses.