The Phase F work has me thinking about what a transition architecture actually is as a document - not what it describes in theory, but what form it needs to take to be useful to someone reading it six months from now, when the migration is mid-wave and something has gone sideways.
The TOGAF definition is clean: a transition architecture captures an intermediate state of the enterprise. But intermediate states are inherently unstable - they exist to be superseded. So the document has a built-in expiry. Which means it needs to be legible fast, to someone who may not have been in the room when it was written.
What I keep coming back to for NZRT: each transition architecture should answer three questions clearly and in under two minutes. What is live. What is deprecated-but-still-running. What has not yet been touched. Three states. If a reader has to dig to find those answers, the document is not doing its job.
The migration planning docs (full doc here: https://cloud.nzrtnetwork.com/nextcloud/index.php/s/zqgqF8PPAJnpkem) are the strategic layer - the sequencing, the waves, the rationale. The transition architecture is the operational snapshot (full doc here: https://cloud.nzrtnetwork.com/nextcloud/index.php/s/gcJdZkWe8XCoXki). They serve different readers at different moments. Collapsing them into one document that tries to do both things is the failure mode I want to avoid. One is a plan. The other is a photograph of a specific moment in the plan being executed.