- App log — the RTT/UART output your firmware prints. What the application thinks happened.
- HCI (host-controller bus) — the Host Controller Interface event stream, decoded to human-readable BLE events. What the host actually told the controller to do, and what came back.
- Over-the-air radio — the sniffer capture. What actually hit the air.

The guided sample run walks the sniffer setup step by step, reading curated nRF knowledge and rendering the hardware diagram for you.
Try it with no hardware
The fastest way to see it is the guided sample run, on a bundled sample with nothing of your own open:1
Open the guided 3-layer debug
From the home, pick the three-layer BLE debug sample. No board, no key, no project of your own needed.
2
Watch a real bug surface across the layers
The walkthrough follows a real one-directional BLE bug: the app log is blind to it, the HCI bus shows the gap, and the over-the-air capture confirms it, landing on the one-line fix.
3
Take it live (optional)
The same debugging runs on your own nRF boards. The guided run walks you through the sniffer-dongle setup, including the hardware steps, so you can capture the radio layer on your bench.
How it works
The agent loads a curated nRF debug workflow and the relevant board knowledge, then walks the steps with you. It parses the HCI event stream into readable BLE protocol events, correlates the three layers against each other, and points at the exact place a flow broke, rather than dumping packets for you to read. The radio layer uses a standard nRF52840 dongle as the sniffer; the walkthrough handles the DFU-mode and firmware-flashing setup. It bridges into the CRA readiness check too: once you understand a BLE flow, you can check the same build’s secure-by-design posture in one click.Scope and honesty
- Available for Nordic nRF BLE projects today (
CONFIG_BTdetected). Extending 3-layer decoding beyond BLE is on the roadmap. - Adsum is an AI-based coding agent and can make mistakes. It narrates the decode and proposes the fix; you confirm it on your hardware.

