A2A Handoff

Transfer the smallest complete state the receiving agent needs.

Native A2A

• Preserve existing Task.id and contextId. A Message.taskId references that Task.id; surface identifier mismatches and let the native runtime assign missing identifiers.
• Use the exact native TaskState enum inside TaskStatus; do not emit fallback aliases in native objects.
• Use Message for instructions, clarification, approval requests, or status.
• Use Artifact with Part values for task outputs; do not put a critical result only in a transient Message.
• Follow the host schema. A2A 1.0.0 is the semantic reference; this skill does not implement transport, discovery, authentication, streaming, push, or Agent Cards.

Choose the matching native state; do not use TASK_STATE_UNSPECIFIED when the lifecycle state is known:

• TASK_STATE_SUBMITTED, TASK_STATE_WORKING;
• TASK_STATE_INPUT_REQUIRED, TASK_STATE_AUTH_REQUIRED;
• TASK_STATE_COMPLETED, TASK_STATE_FAILED, TASK_STATE_REJECTED, TASK_STATE_CANCELED.

Terminal states stay terminal. Completion requires the delegated objective and decisive outputs. Use TASK_STATE_INPUT_REQUIRED for missing product or task content: a choice, fact, or other required input. Use TASK_STATE_AUTH_REQUIRED when an operation lacks required human approval or authorization, or when authentication or credentials are missing. If the host lacks an equivalent state, keep a valid host state and describe the dependency in TaskStatus.message.