Agent names using `%n` now receive a random suffix

Agent names containing %n now receive a random six-character alphanumeric suffix instead of the next available number. For example, cool-agent-%n, which previously produced a name such as cool-agent-123, now produces a name such as cool-agent-aB3dE6.

We deprecated %n in 2022 because allocating sequential agent names becomes increasingly expensive as organizations scale. Removing the sequential allocation improves the speed and reliability of agent registration, particularly when many agents connect at once.

Agents configured with %n will continue to connect and accept work. However, if you have scripts, dashboards, or other automation that expects agent names to end in a number, update them to accept a six-character alphanumeric suffix.

We still recommend replacing %n in your agent configuration. Depending on your setup, use %hostname, %hostname-%spawn, or %random. See the agent name configuration documentation for details.

Questions or need a hand? Reach out to support@buildkite.com or your account team.