代理框架
Google ADK Go 2.3 Brings Context Compaction to the Service Layer and Tightens A2A and Tool-Confirmation Boundaries
The new release can compact agent history after a call completes or during an individual call, recording compaction details as session events. The update also fixes trust boundaries around cross-agent transfers and human tool confirmation; teams upgrading should retest continuation semantics for long-running tasks.
Google released Agent Development Kit for Go 2.3.0 on August 31. The main change is not another agent abstraction, but the integration of context compaction for long-running sessions across all service entry points. The runtime can now summarize older events after a call completes or compact them when an in-progress call exceeds a threshold. Summaries are stored as session events, while content marked as persistent facts is retained during subsequent summarization.
This design gives REST, A2A, and other launch interfaces a shared set of compaction semantics, avoiding a situation in which context length can be controlled only by specific front ends. For long-running coding agents or multi-tool workflows, it can reduce the tokens and latency associated with resending the full history, as well as the risk of exceeding the model’s context window. However, summarization remains a lossy transformation: if file versions, outstanding commitments, tool-call IDs, or negative constraints are not preserved, the agent may take incorrect actions when execution resumes. Existing ADK documentation describes token thresholds, event-retention counts, and two sliding-window strategies, but the supported-versions table does not yet list Go. Deployers should therefore rely on the 2.3.0 APIs and their own tests.
The security-related fixes are equally noteworthy. The new release rejects attempts to restore tool confirmation from non-agent events and blocks conflicting confirmation requests. A2A remote agents can no longer arbitrarily alter control flow through peer-supplied `transferToAgent` metadata, and agent-card sources are now restricted to HTTP(S) URLs or local paths. After upgrading, engineering teams should replay existing pause-and-resume traces, verify that tool results, human approvals, and branch state remain consistent before and after compaction, and monitor the additional cost and distortion rate introduced by summarization calls.