Glossary¶

This page defines the terms the documentation uses, each with one meaning.

A2A: The Agent2Agent protocol. Agent Kourier speaks A2A 1.0 over JSON-RPC, and A2A 0.3 to an agent whose card is a 0.3 card, and needs an agent that streams.
AgentBackend: The resource that names an A2A endpoint and the dialect to speak to it. Owned by the platform team.
Binding: The resource that connects one agent to one channel, with the service identity every turn runs as. Owned by an application team.
Binding identity: The one service identity, a bearer token or a user ID, that every turn of a Binding runs as, chat or alert. The person who wrote a message is carried as attribution, never as the identity.
Channel: A place in a chat platform where people post, named by its ID. One channel takes at most one Binding per connection.
ChatConnection: The resource that connects Agent Kourier to one chat platform workspace, with the Secret that holds its tokens. Owned by the platform team.
Context: The A2A contextId that a session maps to. Agent Kourier resumes the same context for every turn of a thread.
Cooldown: For a botMessage trigger with thread.by: key: the window after an investigation starts in which another fire of the same key adds a note and starts no turn.
Dialect: The per-backend part of the A2A client: URL layout, card location, identity header and how a pause is read. a2a is generic; kagent-v1 adds kagent's human-in-the-loop extension.
Digest line: One line at the top level of a channel that counts the alerts a trigger's limits stopped in a window.
Epoch: With Postgres, the leadership number in the database. A replica that takes the Lease increments it, and every write transaction checks it, so a deposed leader's writes fail. This is the fencing of a leader.
Failover: The standby taking the Lease after the leader stops, is lost or is paused past its renew deadline, and running the same recovery as a restart.
Front door: A proxy in front of an agent runtime that verifies the Binding's token and strips the headers that select a user. Required in front of kagent.
Interaction: A pause in which the agent waits for a person: a question (ask-user), or a tool approval, which is not built yet.
Investigation: A session that a trigger or an alert started rather than a person.
Lease: The Kubernetes Lease, <fullname>-leader, that the replicas on Postgres hold to elect the leader. The leader renews it; a standby takes it a lease duration after the last renewal it saw.
Leader: With Postgres, the one replica that does Agent Kourier's work, chosen by a Kubernetes Lease. Its writes are fenced by an epoch in the database.
Outbox: The durable table of posts Agent Kourier means to make. A post is recorded before it is sent, so a crash between sending and recording is found and not posted twice.
Platform: A chat platform behind the chat.Platform interface. Slack is the one platform in v1.
Post: A message Agent Kourier writes into a channel or thread.
Preset: A named set of botMessage trigger defaults for a known sender. v1 has one, alertmanager.
Redaction: Taking secrets out of text before it is shown, stored, logged or sent to an agent.
Reply queue: The durable queue of thread replies that wait for the agent's active task to end.
Session: The conversation between a thread and an agent context, stored by Agent Kourier. A thread is a session.
Standby: With Postgres, a replica that does not hold the Lease. It is Ready, serves health and metrics, does no work and waits to take the Lease.
Thread: A message and its replies. Agent Kourier owns a thread it started, or one it was mentioned in.
Trigger: A rule in a Binding's chat.triggers that decides what starts a turn: mention, or botMessage for another bot's posts.
Turn: One message to the agent and the task that answers it. A session's turns run one at a time, in order.
Untrusted block: Text from people or other bots that reaches an agent, framed as data inside a tagged block that says it is never instructions.