Is it allowed to augment built-in YANG modules?


I am currently using Confd-6.4.3 and I am trying to augment the ‘get-config’ rpc that is defined in the built-in YANG module ietf-netconf.

In order to do so, I created and compiled the following YANG module:

module test {
 namespace "my:test";
 prefix test;

 import ietf-netconf { prefix nc; }

 augment /nc:get-config/nc:input {
   leaf dummy {
     type string;

But when I started Confd, I got the following error:
Failed to load file ./test.fxs: Missing augment path /get-config in module ietf-netconf, augmented from module test.

Does this mean that it is forbidden to augment built-in YANG modules ?

Thanks for your help,

No, that error doesn’t mean that, but in general it can be problematic to do it. This particular error is due to the fact that since the ietf-netconf module is actually the specification of the NETCONF protocol, which is implemented “directly” in the NETCONF server code, the ietf-netconf module isn’t really loaded as-is.

But if it had worked, that augmentation would definitely have been “problematic” if actually used - what did you expect to achieve with it? The get-config RPC is of course completely implemented in the NETCONF server - how would it know what to do with the additional leaf in the input if it was provided?