I have the following snmpd.conf config file:

# System Information
sysLocation    My Desk
sysContact     Me me@me.com
sysServices    72

# SNMPv3 user (optional)
rouser authPrivUser authpriv

# Agent Address (IPv4 and IPv6)
agentaddress  127.0.0.1,[::1]

# Views: Define accessible OIDs
view   systemonly  included   .1.3.6.1.2.1.1
view   systemonly  included   .1.3.6.1.2.1.25.1

# SNMP Community Strings
rocommunity  public default -V systemonly
rocommunity6 public default -V systemonly

# Include additional configuration files
includeDir /etc/snmp/snmpd.conf.d

###############################################################################
# Custom OID Mapping
###############################################################################

# Pass OID to custom script
view all included .1.3.6.1.4.1
extend .1.3.6.1.4.1.8008.1 lightlevel /usr/bin/python3 /path/to/snmp_serial_handler.py

The script /snmp_serial_handler.py outputs a number when run, and works fine. However, when I run an snmpget: snmpget -v2c -c public localhost .1.3.6.1.4.1.8008.1 I get:

iso.3.6.1.4.1.8008.1 = No Such Object available on this agent at this OID

I've restarted snmpd when making a change. I've tried different OIDs with no luck. Anyone gotten this working?