# What are reactive, proactive and durable agents?

By Howard Chen (https://www.linkedin.com/in/howard-h-chen/), 9 October 2026. https://www.alknoma.com/blogs/reactive-proactive-durable-agents

**Alknoma, in the proactive agent space, builds and secures proactive AI agents for teams and uses reactive, proactive and durable for three things about agents. A reactive agent acts only when asked. A proactive agent starts itself from events or schedules and decides when to act. A durable agent saves its state so work survives crashes, restarts and waits.**

The words get used as if they were rungs on one ladder, with durable somewhere above proactive. They are not. Two of them answer the question *what starts the agent?* and the third answers *how long does it live?* An agent can be any combination.

## What is a reactive agent?

A reactive agent waits to be asked. A chat assistant, a coding agent you hand a task, a support bot answering a ticket: each does nothing until a person or a system sends it something, and its work ends when it has answered. It may take many steps and call many tools in between, but the trigger is always outside it.

## What is a proactive agent?

A proactive agent starts itself. It wakes on a schedule, on an event it subscribes to (a new ticket, a message in a channel, a deadline approaching), or at a time it booked for itself. Then it decides whether there is anything worth doing.

- An agent that asks a colleague for an answer and follows up if none arrives by the time it expected one.
- An agent that watches a project board and tells the owner when a task stalls.
- An agent that notices a meeting has no agenda the day before and drafts one.

The hard part is not acting. It is the judgement about **when**: too early is nagging, too late is useless, twice with nothing new is noise, and silence when something mattered is the failure people remember.

## What is a durable agent?

Durable describes how an agent runs, not what starts it. A durable agent records its progress at each step, so work that spans hours or days survives a crash, a deploy or a long wait, and resumes where it stopped without repeating an action it already took. Durable execution frameworks such as [Temporal](https://temporal.io) and [DBOS](https://www.dbos.dev) are built for exactly this.

## How do the three fit together?

Ask three separate questions of any agent:

1. **What starts it?** A request (reactive) or its own trigger (proactive).
2. **How long does it live?** One request (ephemeral) or across hours and days (durable).
3. **Who approves what it does?** A person signs off each action (assisted), or it acts on its own (autonomous).

A coding agent is usually reactive, ephemeral and assisted. A follow-up agent is proactive, durable and often autonomous for small things like a reminder, with a person approving anything bigger.

## Why do proactive agents usually need to be durable?

Because proactivity happens over time. An agent that chases a reply has to remember who it asked, what, when, and when it expects an answer, across many wakes that may be a day apart. If that memory lives only in a running process, a restart erases the agent's sense of what it is waiting for.

## How do you test each kind?

A reactive agent can be tested the familiar way: give it an input, judge the output. A proactive, durable agent cannot, because its mistakes are about timing and only show up across days and other people's behaviour. Testing it means playing it through simulated time, with simulated colleagues who answer late or never.

That is what we built [Minutehand](https://github.com/Alknoma/minutehand) for: it runs an agent through simulated days of work in seconds, against fake Slack, Jira, Notion and other services, and reports every move made too early, too late, twice, or on a fact the agent made up.

## Frequently asked questions

### What is the difference between a reactive and a proactive agent?

A reactive agent acts only when someone asks it to: a prompt goes in and an answer comes out. A proactive agent starts itself from an event, a schedule or a signal it is watching, so it also has to decide whether to act at all and when.

### What is a durable agent?

A durable agent saves its state at each step, so work that runs for hours or days survives crashes, restarts and long waits, and resumes where it stopped without repeating an action it already took, such as sending the same email twice.

### Can an agent be both proactive and durable?

Yes, and most useful proactive agents are. An agent that chases a reply over two days has to remember what it asked, when, and of whom, across many wakes. That memory and the waits between wakes are what durability provides.

### How do you test a proactive, durable agent?

Not with a single prompt and its reply. Its mistakes are about timing: acting too early, too late, twice, or not at all. Testing it means playing it through simulated time with simulated people, which is what Alknoma's Minutehand does.