Proactive Agents
Up to now, the agent only acts when you send it a message. You ask, it responds. But the most powerful agents do not wait to be asked — they act on their own. This is what makes an agent feel like a true teammate rather than a tool you have to remember to use.
There are two concepts that enable this: schedules and heartbeats.
Schedules
Section titled “Schedules”A schedule runs your agent at a specific time with a predefined message.
For example: every day at 9 AM, run the sleep coach agent with this message:
Fetch my Oura data for last night, analyze it, and send me a briefing to prepare for the day ahead.
You set it up once. From then on, the agent runs at the scheduled time, executes its task, and sends you the result — without you needing to remember to ask.
You can have as many schedules per agent as you like. A task management agent might have a morning schedule for daily priorities and an evening schedule for a daily review. A research agent might run every Monday to summarize what happened in your industry last week.
Designing schedule prompts
Section titled “Designing schedule prompts”The scheduled message is the input that triggers the agent, so it matters. A good schedule prompt is focused: it tells the agent exactly what to do in this specific run. The agent’s system prompt, responsibilities, and skills provide the broader context — the schedule prompt provides the specific task.
Heartbeats
Section titled “Heartbeats”A heartbeat is a recurring run — the agent is triggered every set interval with a predefined message.
The concept is similar to a schedule, but the key difference is intent. A schedule is for a specific task at a specific time. A heartbeat gives the agent ongoing awareness, with the freedom to decide whether it needs to act or not.
For example: run the sleep coach agent every hour between 7 AM and noon with this message:
Check if last night’s sleep data has already been analyzed. If it has, do nothing. If not, fetch it from Oura. If the data is available, analyze it and send the user a briefing for their day. Remember that you have already done this so you do not repeat it on the next heartbeat.
Notice the difference. The schedule prompt says “do this now.” The heartbeat prompt says “assess the situation and act if needed.” The heartbeat agent must be aware of context — what has already happened, what has changed, what still needs attention.
Why heartbeats are powerful — and hard
Section titled “Why heartbeats are powerful — and hard”When heartbeats work well, the result is remarkable. The agent feels genuinely intelligent — it notices things, responds to changing situations, and takes initiative without being asked. It behaves like a thoughtful teammate who is always paying attention.
But designing heartbeat prompts is one of the hardest parts of agent engineering. The heartbeat runs in many different situations, and the agent must make good decisions in all of them. The prompt interacts with the system prompt, the responsibilities, the skills, and whatever the agent discovers through its tools. Predicting what the agent will do across all these combinations is difficult.
Start with simple, well-scoped heartbeats. Test them. Refine the prompts as you learn how the agent behaves. This is where the craft of agent engineering really shows.
Proactive agents change the relationship between you and your agents. Instead of being tools you reach for, they become teammates that are always working — checking in, following up, noticing things, and taking action when needed.
For the craft of designing schedule messages and heartbeat prompts well, see the Agent Design Guide sections on Schedules and Heartbeat.