# How do you build alerts for major probability changes? | Octagon

Build probability alerts by defining a baseline, a trigger threshold, and a delivery channel, then filtering for liquidity and a catalyst so you are…

# How do you build alerts for major probability changes?
 By [Ken So](https://www.octagonai.co/about/#ken-so), Octagon Research Editor

 You build a useful alert by pairing a clear trigger, such as a probability move past a set threshold on a liquid contract, with a delivery channel and a noise filter, so you are notified when an outcome's odds shift for a real reason.

 ## Detailed Explanation
 Set the trigger precisely. Decide whether the alert fires on an absolute change, a percentage change, or a level crossing. "Notify me if recession-by-year-end odds move five points" is a better trigger than "watch this market," because it has a clear condition.

 Add a liquidity filter. A move on a thin book is often noise. Require a minimum liquidity or size so the alert fires on consensus shifts, not single trades. This is the same discipline described in [what makes a signal trustworthy versus noisy](/answers/what-makes-a-prediction-market-signal-trustworthy-versus-noisy).

 Tie the move to a catalyst. The most actionable alerts arrive with context. Linking the trigger to the [news feed](/news/) tells you whether a filing or data release drove the move, or whether it is an unexplained spike worth distrusting.

 Choose a channel and a cadence. Route alerts to email, chat, or an agent, and decide between instant and digest. Instant suits scheduled catalysts, while a daily digest suits a broad watchlist. You can wire this through the [Octagon API or MCP server](/docs/guide/mcp-server).

 ## Common Scenarios

 - A threshold alert on a single high-stakes event into its resolution date
 - A digest of the biggest overnight moves across a watchlist
 - An instant alert tied to a scheduled release like CPI or an FOMC decision
 - A liquidity-change alert that flags when a market becomes tradeable

 ## Exceptions & Edge Cases

 - If your threshold is too tight, you get alert fatigue, so calibrate to how you actually act.
 - If you alert on illiquid markets, expect reversals right after the trigger.
 - If an alert has no catalyst attached, treat it as a prompt to investigate, not to act.

 ## Practical Examples
 Build task: "Alert me on major Fed-path repricings only."

 - Pick the rate-decision contracts and set a five-point trigger
 - Require liquidity above your minimum
 - Deliver instantly around FOMC and CPI, with a news snippet attached
 - Send everything else to a once-daily digest. Start in the [API playground](https://app.octagonai.co/playground).

 ## Actionable Takeaways

 - ✅ Define the trigger as a concrete numeric condition
 - ✅ Filter by liquidity to avoid noise
 - ✅ Attach a catalyst so alerts are actionable
 - ✅ Match instant vs digest to how you trade

 Related: [How do you monitor prediction market moves automatically?](/answers/how-do-you-monitor-prediction-market-moves-automatically) · [Why do prediction market probabilities change so quickly after news events?](/answers/why-do-prediction-market-probabilities-change-so-quickly-after-news-events)

  [Track this in Octagon →](https://app.octagonai.co/playground) [Browse live market research →](/markets/) [Set up alerts →](https://app.octagonai.co/subscribe)

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