What changed
On October 9, Microsoft published its Agent Experience Practitioner Playbook and announced a companion skill. The method pulls together the company's work on how coding agents use developer technologies, with evaluation work dating back to fall 2025. It covers acceptance criteria, evidence that code runs, diagnosis from agent trajectories and testing changes to documentation or extensions. Microsoft describes failures where an extension never loaded, loaded without being called, or was called incorrectly. These are different faults with different repairs. The publication is new; the underlying work is an accumulated practice.
Source: Introducing the Agent Experience (AX) Practitioner Playbook · 2026-10-09 · Primary source context · attributed account
Why it matters
The agent can produce a plausible project while handing the next person an obsolete SDK or an authentication pattern they cannot support. A passing description of that project is not much consolation. Silver Owl's reading is that this playbook points toward a useful shift: evaluate what the user receives, then follow the failure back to the material the agent encountered. Documentation is part of the product when software writes software. A clear example or discoverable tool can change behavior, but the team still needs evidence that the particular change helped.
Source: Introducing the Agent Experience (AX) Practitioner Playbook · 2026-10-09 · Primary source context · attributed account
What to check
Start with one ordinary developer task and define success before running it. Keep compilation, execution and intended platform use as separate checks. Inspect the trajectory when the result fails; avoid treating every error as a model problem. Retain an unchanged comparison task when testing a documentation fix. Microsoft's experience supports trying the method, not assuming its reported results transfer to your stack. A companion skill should also be evaluated as assistance with the method, rather than accepted as the independent judge of its own advice.
Source: Introducing the Agent Experience (AX) Practitioner Playbook · 2026-10-09 · Primary source context · attributed account