AI agents have achieved remarkable progress in automating tasks such as debugging software and booking travel. Yet, these same systems often falter when asked to simply "wait", like monitoring an inbox for a key response or tracking a price change over several days.
Unlike humans, most current AI agents either check too frequently, draining resources, or abandon the task too soon, missing critical opportunities. This shortcoming exposes a crucial gap in how AI handles the real-world need for patient, long-term monitoring.
Key Takeaways
- Core Problem: Current LLM agents fail at long-running monitoring tasks (like watching a price) because they don't know when to check, either checking obsessively or giving up.
- SentinelStep: Is a new mechanism that enables agents to "wait, monitor, and act" patiently and efficiently.
- Dynamic Polling: The agent intelligently guesses and adjusts its check-in interval (e.g., checking email differently than quarterly earnings) to avoid wasting resources.
- Context Management: It saves and reuses the agent's state for each check, preventing "context overflow" and failure on tasks that last for hours or days.
- Evaluation Challenge: Testing monitoring tasks is difficult because real-world target events (like a GitHub repo hitting 10,000 stars) only happen once.
- Evaluation Tool (SentinelBench): A new synthetic web environment created to provide repeatable scenarios (like a flight or message monitor) for reliably testing agents.
- Baseline Improvements: SentinelStep markedly improves task reliability on longer tasks (1-2 hours), with success rates jumping from ~5.6% to over 33%.
- Overall Goal: To create practical, proactive, and "always-on" AI assistants that can handle long-running tasks efficiently without constant supervision.
SentinelStep: A Solution for Smarter Monitoring
To address this, Microsoft Research has developed SentinelStep, a new mechanism designed to empower AI agents with the ability to monitor ongoing conditions effectively. Integrated into the Magentic-UI platform, SentinelStep allows users to configure agents that can patiently wait and only act when specific criteria are met. This innovation applies to a wide range of tasks, from web browsing to code execution and seamless tool integration.
How SentinelStep Optimizes Waiting
The main challenge with monitoring is determining when to check for changes. If an agent checks too often, it wastes computational resources; if it checks too rarely, it could miss important events.
SentinelStep intelligently adjusts its polling interval based on the demands of each task. For example, monitoring email might require frequent checks, while awaiting quarterly financial reports could be spaced out much further. Crucially, SentinelStep manages the agent’s memory by efficiently saving and reusing context, so the agent doesn’t lose its place during extended waits.
- Action: The specific task the agent performs (e.g., checking an inbox, scraping data).
- Condition: The success trigger for the monitoring task (e.g., “message received,” “price drops”).
- Polling Interval: How frequently the agent checks for updates—automatically tuned by SentinelStep.
Users can review and adjust these parameters through Magentic-UI’s co-planning interface, giving them direct control over the agent’s monitoring strategy.
Orchestrating Teams of AI Agents
Magentic-UI’s orchestrator assigns specialized agents for tasks like browsing, code execution, or connecting with external tools. During monitoring, the orchestrator only allows agents to proceed when the specified conditions are met, resetting the agent’s state as necessary to prevent memory overload. This coordination ensures that multiple agents can handle complex, long-running workflows efficiently and reliably.
Reliable Benchmarking with SentinelBench
To systematically test SentinelStep, Microsoft created SentinelBench: a suite of synthetic environments designed for repeatable monitoring experiments. SentinelBench spans 28 configurable scenarios, from simulating GitHub project milestones and urgent messages to tracking dynamic flight prices. This benchmarking tool enables researchers to assess how well agents perform over different timeframes and monitoring challenges.
Results from these tests are promising. For two-hour monitoring tasks, SentinelStep increased success rates from just 5.6% to nearly 39%, demonstrating that the system can sustain performance over long durations, a crucial capability for always-on digital assistants.
Real-World Impact and Accessibility
By adopting SentinelStep, AI agents become far more capable of patient, resource-conscious monitoring and timely action. This advancement paves the way for more proactive and efficient digital assistants. The technology is open source, available via GitHub or by installing magnetic-ui with pip. Microsoft encourages thorough validation before deploying SentinelStep in production and provides clear guidance on usage, privacy, and safety in its transparency documentation.
Toward Trustworthy AI Assistants
SentinelStep represents a significant leap toward AI agents that can genuinely support the patience and vigilance needed in real-world workflows. By enabling agents to wait, monitor, and act at just the right moment, this technology stands to redefine how digital work is managed, ushering in a new era of trustworthy, long-term automation.

GRAPHIC APPAREL SHOP
Patience for Progress: How SentinelStep Lets AI Agents Wait, Monitor, and Act Like Humans