Google AX still warns of major breaking changes before a stable release. GKE Agent Substrate is open for evaluation, but production support requires an allowlist. These statuses differ from OpenShell's qualified stable-release production contract.

Maturity must be checked for each component

AX's current README describes heavy development and warns that core concepts and protocols can change incompatibly before stability.

The GKE Agent Substrate support page distinguishes general evaluation/non-production access from production support offered through a private GA allowlist. This does not establish general production support for arbitrary upstream configurations.

Compare the separate OpenShell stable-release finding. These are published support positions, not independently measured reliability rankings. No head-to-head operational test was performed.