Summary
Following its earlier observability push, Claude Code v2.1.146 and v2.1.147 added more durable background sessions that persist through idle periods, restart in place for updates, and are shed last under memory pressure. The same release cluster also renamed /simplify to /code-review, turning it into a more explicit code-review surface that can report correctness bugs rather than only cleanup suggestions.
What changed
Claude Code expanded its background-agent release line with pinned session durability improvements and replaced /simplify with /code-review as a more explicit review workflow.
Why it matters
This deepens the product's shift from interactive terminal helper toward long-running agent operations. Durable background sessions matter for multi-hour work, while a named code-review command turns quality checking into a first-class workflow instead of an improvised prompt pattern.
Evidence excerpt
Anthropic's release notes say background sessions now persist through idle periods and are shed last under memory pressure, while /simplify was renamed to /code-review and now reports correctness bugs.