When extending Termux API (Android/Java code), use Android's Log class with the exception as a third argument — it prints the full stack trace to logcat:

import android.util.Log;

private static final String TAG = "MyTermuxPlugin";

try {
    // your code
} catch (Exception e) {
    Log.e(TAG, "Something went wrong", e);  // full stack trace in logcat
}

Alternatives:

• Get the trace as a String (e.g. for returning to the Termux shell via stdout, or sending back in a Result/error message):

String stackTrace = Log.getStackTraceString(e);

• Kotlin:

try {
    // ...
} catch (e: Exception) {
    Log.e(TAG, "Something went wrong", e)
}

View output with:

logcat -s MyTermuxPlugin:E

Tip: Termux API command methods run on a background thread (onReceive via Thread/executor in TermuxApiReceiver), so exceptions there won't crash the app but can be silently swallowed — always wrap the body in try/catch and log with Log.e(TAG, msg, e) so nothing is lost.