Scan: US x Iran ceasefire continues through October 31?

1. Planner Fable 5.1 · Fermi decomposition + tool plan

Tools chosen: polymarket_direct polymarket_related kalshi_related article_search claude_news gdelt_news wikipedia

Sub-questions (Fermi decomposition)

What is the current status of the US-Iran ceasefire (when was it agreed, is it formally in effect, and have there been any reported violations or US strikes on Iranian territory since it began)?
Have there been any credible reports in the last 30 days of US air or missile strikes impacting Iranian territory, or US military buildup/authorizations signaling imminent action?
Are there active US-Iran negotiations (nuclear or otherwise) with deadlines, ultimatums, or snapback/sanctions triggers falling before October 31, 2026?
What escalatory triggers exist: Iranian proxy attacks on US forces, Strait of Hormuz incidents, resumption of uranium enrichment, or Israeli strikes that the US might join?
How are the sibling monthly Polymarket markets (ceasefire continues through earlier/later months) and any Kalshi US-Iran strike markets priced, and did prior months resolve Yes?
What is the historical base rate of the US initiating direct strikes on Iranian soil in any given month, and how has the ceasefire held month-to-month so far?

Planner reasoning

This is a Polymarket market that resolves No only if the US itself conducts an air or missile strike that impacts Iranian soil before Oct 31, 2026. The key drivers are the current state of the US-Iran ceasefire, any active negotiations or deadlines, escalatory triggers (proxy attacks, nuclear activity, Israeli action), and how the market and its sibling monthly markets are priced. The direct market price is the primary anchor, with news and cross-market checks to detect any near-term escalation.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.2s	1	## This Market's Polymarket Data US x Iran ceasefire continues through October 31? - Current price (probability): 47.00% - 7-day price change: -6.50% - 30-day price change: -6.50% - Total volume: $56,116 (USD notional) - Price range: 47.00% - 53.50% - Data points: 2 days
polymarket_related	OK	0.5s	11	Polymarket search over 4 keyword(s), kept 11 matches. keyword 'Iran ceasefire': 6 markets \| keyword 'US strikes Iran': 1 markets \| keyword 'Iran military action': 0 markets \| keyword 'Israel Iran': 4 markets
kalshi_related	OK	2.5s	1	1 related markets / summaries. keyword 'Iran strike': ok \| keyword 'US Iran': no matches \| keyword 'Iran ceasefire': no matches
article_search	OK	1.0s	22	Fetched 22 unique articles across 5 queries (lookback=30d). 'US Iran ceasefire status': 10 articles \| 'US strike Iran': 10 articles \| 'Iran nuclear talks deadline': 10 articles \| 'Iran Israel strikes United States': 10 articles \| 'Strait of Hormuz Iran US Navy': 10 articles
claude_news	OK	23.5s	10	Based on research, the situation is far more complex than a simple "ceasefire" question implies — there has been a full-scale, ongoing US-Israel-Iran war since February 2026, with multiple broken ceasefires and a current uneasy "fire pause" as of mid-September 2026. Key findings: - **War outbr
gdelt_news	FAILED	240.0s	0	timeout after 240.0s
wikipedia	OK	0.3s	3	Fetched 3 Wikipedia entries (0 missing pages).

3. Evidence Brief Sonnet 5 · 7370 chars

# Current state There is no formal, durable US-Iran ceasefire — rather an on/off war (since Feb 28, 2026) marked by repeated truces, breakdowns, and a fragile "fire pause" since ~Sept 8, 2026. As of the latest data (Sept 18, 2026), no US strike has hit Iranian territory for ~11 operational periods, but naval/tanker attacks and Hormuz blockade actions continue; this market resolves "No" only on a qualifying air/surface-to-surface strike on Iranian soil, which has happened repeatedly in prior months (most recently ~Aug 30-Sept 5, 2026). # Timeline of key events - 2026-02-28: US-Israel joint strikes on Iran begin war; Khamenei assassinated (confirmed, Wikipedia). - 2026-04-07/08: Ceasefire begins; strained after Iran resumes Hormuz blockade; Islamabad talks (Apr 12-13) fail; US imposes naval blockade (confirmed, CNN/Wikipedia). - 2026-06-14/17: US-Iran halt hostilities; MOU signed at Versailles (June 17) with 60-day deadline for permanent deal, uranium reduction, Hormuz reopening (confirmed, Wikipedia). - 2026-07-29: Last reported US strike on Iran before the Aug 30 resumption (confirmed via CNN reference). - 2026-07 (mid-late): Trump declares ceasefire deal "over" at NATO summit amid tanker strikes (reported, ABC News). - 2026-08-17: 60-day MOU deadline expires with no deal; talks deadlocked (confirmed, CNN/political.org). - 2026-08-28: NPR reports periodic US airstrikes on Iranian missile/drone facilities continuing post-"ceasefire" (reported). - 2026-08-30: US and Iran trade strikes near Larak Island — first major military escalation in a month; direct US strikes on Iranian-linked targets (confirmed, CNN). - 2026-09-05: US strikes three Iranian tankers (Kharg Island) in retaliation for missile attacks on a carrier (confirmed, CNN/CBS) — ambiguous whether this counts as "impacting Iranian territory" under market rules (tankers/naval vs. land). - 2026-09-06: Iran announces new Hormuz "exclusion zone" (reported). - 2026-09-15: Tanker attack near Musandam, Oman-side waters (reported, Times of Israel) — not Iranian territory. - 2026-09-16: Iranian officials claim nuclear issue "taken care of"; Iran scores diplomatic point at IAEA (reported, Bloomberg/CBS). - 2026-09-18: Day 203 update — 9th day of fire pause, no new land strikes on Iran for 11 periods, Iranian air defenses ~90% degraded, rial collapsing (reported, GlobalSecurity.org). # Event Will the current US-Iran "ceasefire" (no qualifying US air/missile strike hitting Iranian territory) hold continuously through October 31, 2026? # Outcomes to forecast Yes (no qualifying US strike on Iran by Oct 31, 2026 IRST) / No (qualifying strike occurs). # Kalshi market anchor No kalshi_direct data was returned for this ticker in raw research; the ticker format matches Polymarket's, and the only pricing available is Polymarket_direct: **47% YES** (down from 53.5% high), 7-day and 30-day trend both -6.5%, thin volume ($56k total, only 2 data points) — treat as noisy but directionally bearish for "Yes." # Resolution source Not run / not present in raw research. # Sub-question answers 1. **Ceasefire status/violations** — No formal ceasefire currently; a fragile "fire pause" began ~Sept 8, 2026 after the prior MOU (signed June 17, expired unmet Aug 17) collapsed multiple times, with the most recent confirmed US strikes on Iranian-linked targets around Aug 30–Sept 5, 2026 (CNN, GlobalSecurity.org). 2. **Recent strikes/buildup (30d)** — Yes: US struck near Larak Island (Aug 30) and hit three Iranian tankers near Kharg Island (Sept 5) in retaliation for Iranian attacks; no land strikes reported since (as of Sept 18) but naval blockade/Hormuz tension continues (CNN/CBS/GlobalSecurity). 3. **Negotiations/deadlines** — MOU's 60-day deadline (Aug 17) expired with no deal; US paused negotiations per Trump (CNN, Aug 19); no active deadline before Oct 31 found in research; possible UNSC snapback referral by US/UK/France/Germany over nuclear noncompliance (CBC, Sept 6) could be an escalatory trigger but no confirmed date. 4. **Escalatory triggers** — Iran's repeated targeting of tankers/commercial shipping in Hormuz, US naval blockade/counter-blockade, and an Iranian "exclusion zone" announcement (Sept 6) are the live flashpoints; no direct Israeli-strike-triggers-US-join scenario reported in this window. 5. **Sibling markets** — Polymarket "Israel x Iran ceasefire continues through Oct 31" prices at 82.5% Yes (much higher confidence than this US-Iran market's 47%), suggesting markets see Israel-Iran calm as more durable than US-Iran calm. "US x Iran diplomatic meeting by Oct 31" priced only 28.5% Yes, implying low chance of resumed talks. No prior-month US-Iran ceasefire market resolution data found. 6. **Base rate** — Over ~7 months since Feb 2026, there have been at least 3-4 distinct episodes of US strikes on Iranian-linked targets (Feb, June-July, Aug-Sept), i.e., roughly one qualifying-type escalation every 6-8 weeks — a high recurring base rate. # Key facts 1. [Wikipedia] War began Feb 28, 2026; ceasefire/MOU signed but repeatedly broke down. 2. [CNN, Aug 30] US and Iran "trade attacks, marking first major military escalation in a month" — active hostilities as recently as late Aug/early Sept. 3. [CNN/CBS, Sept 5] US struck three Iranian tankers in retaliation. 4. [GlobalSecurity.org, Sept 18] No land strikes on Iran for 11 operational periods; fire pause 9 days old. 5. [political.org/CNN] 60-day MOU deadline expired Aug 17 with no deal. # Cross-market signals - Polymarket (this market): 47% Yes, falling. - Polymarket sibling: Israel-Iran ceasefire through Oct 31 = 82.5% Yes (much more stable). - Polymarket: US-Iran diplomatic meeting by Oct 31 = 28.5% Yes (talks unlikely to resume). - No sportsbook or Kalshi-direct pricing found. # Analyst opinions and speculation - CNN's McGurk-sourced analysis (Aug 30) argues Iran is not "winning" and US pressure (blockade, sanctions) is intensifying — implies continued/escalating US action likely, not de-escalation. - Middle East Institute's Vatanka: best case is a "compromise," not resolution — implies protracted friction, not clean ceasefire. # Directional lean per outcome - **Yes** (ceasefire holds): Supported by 9-11 day pause in land strikes, degraded Iranian capacity, Polymarket sibling market pricing Israel-Iran calm highly (82.5%). Opposed by pattern of ~6-8 week recurring collapse cycles and unresolved Hormuz/tanker conflict. - **No** (strike occurs): Supported by consistent history of US strikes recurring every 4-8 weeks since Feb 2026, unresolved nuclear dispute, active naval clashes that could escalate to land strikes, falling Polymarket price (53.5%→47%). This is the stronger case given base rate. # Gaps / unknowns - No official Kalshi YES price available for this specific ticker. - Unclear whether Sept 5 tanker strikes (at Kharg Island, arguably Iranian territory/waters) would count as "qualifying" under strict resolution rules — ambiguous precedent. - No data on whether any strike occurred between Sept 18 and question creation/current date. - No UNSC snapback timeline confirmed. # Calibration anchors - Polymarket price (only available anchor): 47% Yes, trending down. - Base rate: strikes/escalations recurring roughly every 6-8 weeks over 7 months of conflict — suggests <50% chance of a full clean month-plus pause holding through Oct 31.

4. Forecasters 5 draws · Fable 5.1 + GPT-5.6 Sol

claude-fable-5-1

42% conf

Yes	44%
No	56%

The only market anchor is Polymarket at 47% Yes and trending down (from 53.5%), on thin volume. The structural picture argues modestly against a clean hold: since Feb 2026 the US has struck Iranian-linked targets in recurring cycles roughly every 4-8 weeks (July 29, Aug 30, Sept 5), the MOU deadline expired Aug 17 with talks paused, and live flashpoints (Hormuz blockade, tanker attacks, Iranian 'exclusion zone', possible UNSC snapback) persist; the pause beginning ~Sept 8 would need to last ~7.5 weeks to reach Oct 31, right at the edge of the historical cycle length. Supporting Yes are the 11-period absence of land strikes, ~90% degraded Iranian air defenses (less reason for new US strikes), and the sibling Israel-Iran market at 82.5% Yes. Netting these, I lean slightly below the market anchor at 44% Yes.

claude-fable-5-1

38% conf

Yes	43%
No	57%

The only market anchor is Polymarket at 47% Yes and falling (from 53.5%), on thin volume. The brief shows no durable ceasefire — only a ~9-11 day 'fire pause' as of Sept 18 following confirmed US strikes around Aug 30–Sept 5 — and a base rate of US escalations recurring roughly every 4-8 weeks since Feb 2026, which closely matches the ~6-week window remaining to Oct 31. Live flashpoints (Hormuz blockade, tanker attacks, Iranian 'exclusion zone', expired MOU with talks paused and a diplomatic-meeting market at only 28.5%) point toward renewed strikes rather than de-escalation, though degraded Iranian capability and the strong Israel-Iran calm pricing (82.5%) offer some support for a hold. I shade slightly below the market toward No given the base rate, while noting resolution ambiguity over whether naval/tanker strikes count as hitting Iranian territory.

claude-fable-5-1

40% conf

Yes	42%
No	58%

The only market anchor is Polymarket at 47% Yes and trending down (from 53.5%), with no Kalshi-direct price available. The brief shows a fragile 'fire pause' only ~9-11 days old as of Sept 18, following a pattern of US strikes on Iranian targets recurring roughly every 4-8 weeks since Feb 2026 (Feb, June-July, Aug 30-Sept 5), and the window to Oct 31 is ~6 weeks — squarely inside that recurrence cycle. Live flashpoints (Hormuz blockade, tanker attacks, Iranian exclusion zone, expired MOU with talks paused and only a 28.5% chance of a diplomatic meeting) make a clean six-week pause less likely than not, though degraded Iranian capacity and the 82.5% Israel-Iran calm pricing offer some support for Yes. Ambiguity over whether naval/tanker strikes qualify as hitting 'Iranian territory' cuts modestly toward Yes, so I stay near but slightly below the market anchor.

gpt-5.6-sol

58% conf

Yes	45%
No	55%

The 47% Polymarket YES price is the best available consensus anchor, though thin volume makes it noisy. The pause in land strikes and Iran's degraded military capacity support Yes, but the absence of a formal ceasefire and failed negotiations leave no durable mechanism sustaining it. Recent tanker attacks, the Hormuz confrontation, and the historical recurrence of US strikes every roughly 6–8 weeks point toward No over the remaining six-week window. Ambiguity over whether naval or tanker strikes qualify prevents a larger move below the market's YES estimate.

gpt-5.6-sol

64% conf

Yes	44%
No	56%

The 47% Polymarket YES price is the best available consensus anchor, though thin volume makes it noisy. The current 9–11 day pause and Iran’s degraded military capacity support Yes, but there is no formal ceasefire or active diplomatic process. Repeated breakdowns, strikes as recently as August 30–September 5, and a roughly 6–8 week escalation cycle point toward No over the remaining six weeks. Continuing Hormuz and tanker confrontations provide a plausible trigger for another qualifying strike, so I shade YES below the market anchor.

6. Final plain mean of 5 draws

44% (48% confidence)

Yes: 44% No: 56%

Mean of 5 draws (0.44, 0.43, 0.42, 0.45, 0.44). The only market anchor is Polymarket at 47% Yes and trending down (from 53.5%), on thin volume. The structural picture argues modestly against a clean hold: since Feb 2026 the US has struck Iranian-linked targets in recurring cycles roughly every 4-8 weeks (July 29, Aug 30, Sept 5), the MOU deadline expired Aug 17 with talks paused, and live flashpoints (Hormuz blockade, tanker attacks, Iranian 'exclusion zone', possible UNSC snapback) persist; the pause beginning ~Sept 8 would need to last ~7.5 weeks to reach Oct 31, right at the edge of the historical cycle length. Supporting Yes are the 11-period absence of land strikes, ~90% degraded Iranian air defenses (less reason for new US strikes), and the sibling Israel-Iran market at 82.5% Yes. Netting these, I lean slightly below the market anchor at 44% Yes.

Pipeline Timing

Total pipeline time: 321.0s

Per-tool research timings shown in the Research section above.