Reading a sequence figure in this manual
Five lifelines: planner, test-runner, the task store of test-runner, a webhook receiver at /a2a-events, and an operator. Eight numbered rows show each arrow style once: SendMessage as a solid ink call, task saved as a solid teal write, TASK_STATE_WORKING as a dashed amber state change, a statusUpdate stream frame and a push POST as dotted indigo events, the planner asking an operator for approval as a dashed olive effect outside A2A, TaskNotFoundError as a dashed rose failure, and the SendMessage result as a dashed ink reply.
planner
client agent
test-runner
remote agent
task store
of test-runner
webhook
/a2a-events
operator
a person
1
SendMessage
a request · solid ink
2
task saved
a write · solid teal
3
TASK_STATE_WORKING
state change · dashed amber
4
statusUpdate
stream frame · dotted indigo
5
push POST
push · dotted indigo
6
asks for approval
outside A2A · dashed olive
7
TaskNotFoundError
an error · dashed rose
8
SendMessage result
a reply · dashed ink