## What changed
- Add a `features.token_budget.mode` setting with `thread` and `name` values.
- Default context-window metadata to the thread ID while allowing configurations to retain the agent name.
- Preserve the selected identity mode when applying model token-budget defaults and replaying locked configuration.
## Testing
- Cover configuration parsing and both identity formats in token-budget context messages.
GitOrigin-RevId: f6e6d2c49e09e70c0352e803bb65784ef77e5bee