Anthropic Release Notes: Five Updates for Claude Managed Agents — Effort Levels, Webhooks, and Session Seeding

Anthropic announced five changes to Claude Managed Agents — agents managed by Anthropic’s platform, meaning they run and are maintained on its infrastructure without the developer having to host their lifecycle themselves — in its platform release notes on July 22, 2026.

How is an agent’s effort level now controlled?

The update allows setting the effort level directly on the agent’s model — a parameter that controls how deeply the model “thinks” before generating a response. Previously, this level was not adjustable at the individual agent level, so developers had to accept the model’s default behavior for all tasks.

Webhooks and session seeding bring broader control

Webhooks now cover lifecycle events for the environment (4 types) and the memory store (3 types) — seven event types in total that the system can automatically report to an external application, instead of the developer manually checking state.

A new session can be immediately “seeded” with up to 50 events of type user.message or user.define_outcome via the initial_events parameter in a POST /v1/sessions call. For comparison, until now every session started empty, with context only building up through subsequent messages — now the agent has a predefined history and goals from the very first moment.

What changes for agent updates and generation tracking?

The version field for agent updates becomes optional — it can be used for optimistic concurrency (checking that no one else modified the agent at the same time) or omitted for an unconditional update. In addition, session thread event streams now support the event_deltas[] parameter, which allows viewing a subagent’s text while it is still being generated, instead of waiting for a complete response.

Conclusion

Together, the five changes expand control over the behavior, monitoring, and initialization of Claude Managed Agents, from effort levels to seeding sessions with predefined events.