You'll noticeTier: how much it should matter to you
2Useful: my rating, 1 to 5
3Signal: worth watching, 1 to 5
Agent SDK DocsArea: what it touches
ImprovementsKind: in v2.1.224,
ImprovementsSection of the release
What
Session update docs now state that vault_ids is rejected on update even though the SDK exposes it as a parameter, so only agent.tools, agent.mcp_servers, title, metadata and budget can change mid-session. Deployments gain an UpdateDeployment endpoint and deployments.update SDK method.
Details
A deployment can carry a budget that is copied onto every session it fires; it can be cleared and added back at the deployment level.
Evidence
`vault_ids is create-only (rejected on update) `
Strings lifted out of the shipped bundle, so the claim above can be checked against them.
