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The same prediction lives on more than one venue, but the venues don’t always settle it the same way. One resolves “US presidential election” on the AP call; another waits for official certification weeks later. One voids a cancelled match; another resolves it 50‑50. Those differences are real settlement risk — and historically a trader had to read three sets of rules to find them. Settlement Key Differences does that reading for you. For any matched cross‑venue event, AGG returns a structured, per‑venue breakdown of how the settlements differ, plus each venue’s full rules — so you can render a “Settlement” panel that tells a user exactly what they’re trading before they trade it. It’s returned automatically on the single event‑detail endpoint — no extra parameter, no extra call.

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What you get

GET /venue-events/:id (or client.getVenueEventById(id)) now includes two fields: 
{
  "id": "evt_…",
  "title": "Who will win the 2028 US presidential election?",

  // The structured differences — drives the "Key differences" cards.
  // null until AGG has computed a diff for the cluster (or when venues settle identically).
  "settlementDiff": {
    "sharedSummary": "All venues track the winner of the 2028 U.S. presidential election.",
    "differences": [
      {
        "type": "resolution_source",            // open enum → pick an icon
        "title": "Resolution source",            // display label
        "perVenue": {                            // a venue is omitted if its rules don't ground a value
          "kalshi": "Official election certification",
          "polymarket": "Associated Press, Fox News, and NBC",
          "predict": "Associated Press and NBC"
        },
        "summary": "Kalshi waits for certification; others resolve on the called result."
      },
      {
        "type": "resolution_timing",
        "title": "Resolution timing",
        "perVenue": { "kalshi": "2029-01-06", "polymarket": "2028-11-08", "predict": "2028-11-08" }
      },
      {
        "type": "edge_cases",
        "title": "Edge cases",
        "perVenue": {
          "kalshi": "Recounts may delay settlement",
          "polymarket": "Resolves after source confirmation"
        }
      }
    ]
  },

  // Each venue's raw rules — drives the "Full rules by venue" expanders.
  "fullRulesByVenue": {
    "polymarket": { "description": "This market resolves to …", "rulesPrimary": null, "rulesSecondary": null },
    "kalshi": { "description": null, "rulesPrimary": "If the candidate …", "rulesSecondary": "…" },
    "predict": { "description": "Resolves per …", "rulesPrimary": null, "rulesSecondary": null }
  }
}
type is an open enum — known values today are resolution_source, resolution_timing, scope, threshold, start_date, end_date, edge_cases, and wording, with other as the catch‑all. Map known types to an icon and fall back to a generic icon for anything else, so a new type is never dropped.

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Fetch it

import { createAggClient } from "@agg-build/sdk";

const client = createAggClient({ baseUrl: "https://api.agg.market", appId: "your-app-id" });

const event = await client.getVenueEventById("evt_123");

if (event.settlementDiff) {
  // render the "Key differences" cards from event.settlementDiff.differences
}
// render the "Full rules by venue" expanders from event.fullRulesByVenue
Settlement data is returned on the single event‑detail endpoint only — it is intentionally not included in the /venue-events listing, where running a per‑event settlement lookup for every row would be wasteful. Fetch it when a user opens an event.

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Render it

The fields map one‑to‑one to a settlement panel:
  1. Key differences — one card per settlementDiff.differences[] entry: the title as the heading, an icon chosen from type, and one row per venue from perVenue (key = venue, value = the short per‑venue value). The card count is differences.length.
  2. Full rules by venue — one expander per venue in fullRulesByVenue. Show rulesPrimary ?? description as the body (venues store their rules in different fields), and keep rulesSecondary for any addendum.
  3. Empty / not‑yet‑computed — when settlementDiff is null or differences is [], the venues settle identically (or AGG hasn’t computed a diff yet); hide the “Key differences” block and just show the full rules.
A drop‑in @agg-build/ui component for this panel is on the roadmap; until then, render from the typed fields above.

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How it’s built

The differences are produced by a small hybrid engine, computed once per matched cross‑venue cluster and persisted — it runs in the background, completely off the trade/quote path, so reading them never adds latency to execution.
  • Deterministic core (no model): the structured facts AGG already ingests — resolution dates, resolution sources, thresholds, market scope — are compared directly across venues. This is exact and grounds the timing/source/threshold/scope differences with zero ambiguity.
  • Language model gap‑fill: for the nuances that only live in prose (edge cases like recounts, walkovers, void conditions, or a resolution source named only in the rules text), a cost‑efficient model reads each venue’s rules and fills the remaining differences — and is only invoked when a venue’s settlement genuinely isn’t captured structurally.
Both paths emit the same structure, and a difference is surfaced only when venues actually diverge and the value can be grounded in a venue’s own rules — AGG omits a venue rather than guess. The result is cached per cluster and refreshed as venues update their rules.