Async Task Polling for Long-Running Agent Jobs

[rbpotter-aws]

Summary

Add support for kicking off long-running agent tasks and polling for completion, leveraging AgentCore Runtime's built-in async processing model. This enables fire-and-forget workflows where a caller can start a multi-minute job, disconnect, and check back for results.

Motivation

Some agent tasks (e.g. data processing, multi-step workflows, report generation) can take several minutes to complete. Today, the caller must hold a connection open for the entire duration. We need a pattern where the caller can:

1. Submit a task and get an immediate acknowledgment
2. Poll for status until the task completes
3. Retrieve the result once ready

Requirements

• Task submission — Accept a request, start processing in the background, and return an immediate response with a task/session identifier.
• Status reporting — Expose task status via AgentCore's /ping health endpoint, using HEALTHY_BUSY while processing and HEALTHY when idle/complete.
• Task lifecycle management — Register tasks on start (add_async_task) and mark them complete (complete_async_task) so the SDK manages ping status automatically.
• Non-blocking entrypoint — Ensure long-running work runs in a background thread or async method so it doesn't block the /ping health check.
• Result retrieval — Allow the caller to re-invoke the same session after the task completes to fetch results.

Constraints

• AgentCore sessions time out after 15 minutes of idle time, so polling must occur within that window.
• Maximum session lifetime is 8 hours.
• While a session reports HEALTHY_BUSY, the runtime will not accept new invocations for that session.

Acceptance Criteria

• A caller can submit a long-running task and receive an immediate response
• Session status reflects HEALTHY_BUSY while the task is in progress
• Session status returns to HEALTHY once the task completes
• Caller can retrieve task results by re-invoking the same session
• The /ping endpoint remains responsive throughout task execution