Comment 1 for bug 1517632

Some experimentation has shown the following.

$ juju --version
1.25.1-wily-amd64

Start out with agent-stream=debug in environments.yaml

$ juju bootstrap --upload-tools
$ juju upgrade-juju --version 1.26-alpha1

The above works.

However, if we bootstrap without the agent-stream set to debug, and then after bootstrap:

$ juju set-env agent-version=debug
$ juju upgrade-juju --version 1.26-alpha1
ERROR cmd supercommand.go:448 no matching tools available

Looking at the server side logs, we see simplestreams data is being read from
"https://streams.canonical.com/juju/tools/streams/v1/index2.sjson"

but there's a claim that information is missing:

machine-0: 2015-11-19 05:31:16 DEBUG juju.environs.simplestreams simplestreams.go:429 read metadata index at "https://streams.canonical.com/juju/tools/streams/v1/index2.sjson"
machine-0: 2015-11-19 05:31:16 DEBUG juju.environs.simplestreams simplestreams.go:433 skipping index "https://streams.canonical.com/juju/tools/streams/v1/index2.sjson" because of missing information: "content-download" data not found

Examining the json data received by Juju shows that the content-download field is not missing and the data is as expected.

Further investigation required.