The contract is small on purpose so any framework fits: environment in, a workspace and an output folder, two audience-bound tokens, and two places to send traffic. Nothing inside holds a credential.
Principle honored
Least privilege by construction. Default-deny egress with two exceptions, no secrets in the namespace (the quota forbids them), a token that names its audience.
Files: /workspace to work in, /run/output for results, tokens under /var/run/hangar.
On SIGTERM, checkpoint within 30 seconds. Sidecars get the same lockdown and no env.
Consequence
Kubernetes has no pod exec here by policy, so a human cannot shell into a run. Debugging is via output, logs and the audit record. Decide whether that is acceptable before promising it to users.