Google ADK (Python) v2.10.0: experimental skill lifecycle, MongoDB toolset, eval efficiency metrics

ADK Python v2.10.0 was published on 2026-09-25 (changelog dated 2026-09-24). The release notes list an experimental skill lifecycle (ephemeral skills and an opt-in unload_skill tool, enabled with ADK_ENABLE_SKILL_LIFECYCLE=1), a MongoDB toolset with vector and hybrid search, evaluation metrics for duration, token use and model call counts, and several behavior changes, including stricter BigQuery protected write mode and AgentEvaluator.evaluate raising ValueError when no eval cases run. Source: v2.10.0 release notes.

Relation to the directory: see Google ADK (Python) and Google ADK vs LangGraph. Projects that run test suites with -W error should read the deprecation note on legacy live-audio modules before upgrading.