You can now set an effort level on a Claude Managed Agents agent's model configuration

Wednesday, 22 July 2026

AI summary

Written by AI from the official notes. Check them for exact details.

Claude Managed Agents now allow setting an effort level and support initial events for sessions.

Why it matters: Developers and users of Claude Managed Agents should care for improved configuration and session management capabilities.

You can now set an effort level on a Claude Managed Agents agent's model configuration. Pass effort inside the model object when you create the agent. See Effort levels for what each level does.
Webhooks for Claude Managed Agents now cover the environment and memory store lifecycle: four environment.* event types and three memory_store.* event types. You can react to environment and memory store lifecycle changes without polling. See the Environment events and Memory store events tabs in Subscribe to webhooks.
When creating a Claude Managed Agents session, you can now seed it with initial events. Pass initial_events on POST /v1/sessions with up to 50 user.message and user.define_outcome events. A non-empty list starts the agent loop in the same call, so you don't need a separate send-events request to start work.
The version field is now optional when updating a Claude Managed Agents agent. Supply it for optimistic concurrency (a mismatch returns a 409 error), or omit it to apply the update unconditionally. See Update semantics.
Claude Managed Agents session thread event streams now support event deltas. GET /v1/sessions/{session_id}/threads/{thread_id}/stream accepts the same event_deltas[] query parameter as the session-level stream, so you can preview a subagent's text as the model generates it. A connection previews only the thread it's reading. See Preview session thread events.

Full release notes5 changes

You can now set an effort level on a Claude Managed Agents agent's model configuration. Pass effort inside the model object when you create the agent. See Effort levels for what each level does.
Webhooks for Claude Managed Agents now cover the environment and memory store lifecycle: four environment.* event types and three memory_store.* event types. You can react to environment and memory store lifecycle changes without polling. See the Environment events and Memory store events tabs in Subscribe to webhooks.
When creating a Claude Managed Agents session, you can now seed it with initial events. Pass initial_events on POST /v1/sessions with up to 50 user.message and user.define_outcome events. A non-empty list starts the agent loop in the same call, so you don't need a separate send-events request to start work.
The version field is now optional when updating a Claude Managed Agents agent. Supply it for optimistic concurrency (a mismatch returns a 409 error), or omit it to apply the update unconditionally. See Update semantics.
Claude Managed Agents session thread event streams now support event deltas. GET /v1/sessions/{session_id}/threads/{thread_id}/stream accepts the same event_deltas[] query parameter as the session-level stream, so you can preview a subagent's text as the model generates it. A connection previews only the thread it's reading. See Preview session thread events.