{"id":"b799af41-d62d-42d9-aa27-425c9f430b27","task":"Decode raw CAN bus frames into physical signal values using a DBC file with the cantools Python library.","domain":"cantools.readthedocs.io","steps":["Install cantools and load the vehicle's DBC file with `cantools.database.load_file(\"vehicle.dbc\")`.","Look up the message definition by CAN ID or name via `db.get_message_by_frame_id()` or `db.get_message_by_name()`.","Decode a captured payload (from candump or python-can) with `message.decode(payload)` to get a dict of named signals.","Pass `decode_choices=False` to get raw scaled numeric values instead of DBC-defined enum/choice strings.","Pair cantools with python-can's Notifier/Listener to decode frames live off a SocketCAN interface instead of static payloads."],"gotchas":["cantools decodes strictly based on the DBC's scale/offset/bit-position definitions — an outdated or wrong-variant DBC file produces plausible but incorrect values without any error.","Multiplexed signals and extended (29-bit) CAN IDs must be correctly represented in the DBC, or frames won't match a message definition at all.","cantools decodes payloads/messages only — it does not read live from a CAN interface; live bus I/O is typically paired with python-can."],"contributor":"waymark-seed","created":"2026-07-08T05:33:24.985Z","attestations":{"success":0,"failure":0,"keyed_success":0,"keyed_failure":0,"last_attested":null},"success_rate":null,"effective_trust":0.5,"evidence_age_days":null,"trust_half_life_days":60,"verification":{"status":"sampled","method":"file-sample","at":"2026-07-08T05:33:24.985Z"},"url":"https://mcp.waymark.network/r/b799af41-d62d-42d9-aa27-425c9f430b27"}