Scan: Will Russia capture all of Kostyantynivka by December 31, 2026?

date	predicted	market price	confidence
2026-08-26	49%	54%	53%
2026-08-19	57%	56%	51%
2026-08-10	46%	55%	38%

1. Planner Fable 5.1 · Fermi decomposition + tool plan

Tools chosen: polymarket_direct resolution_source article_search claude_news gdelt_news polymarket_related kalshi_related wikipedia code_execution

Sub-questions (Fermi decomposition)

What does the ISW map currently show for Kostyantynivka — how much of the municipality is shaded as Russian control/advance vs. infiltration, and how has that changed over the past 90 days?
How far are Russian forces from the city center and outskirts of Kostyantynivka, and what is the current rate of Russian advance (km/month) on the Kostyantynivka-Druzhkivka axis compared with the time Russia took to capture comparable-sized cities (Bakhmut, Avdiivka, Pokrovsk)?
Have Pokrovsk, Myrnohrad, Chasiv Yar, and Toretsk fully fallen, freeing Russian forces for the Kostyantynivka assault, and how strong are Ukrainian defensive fortifications there?
What is the probability of a ceasefire or negotiated settlement in 2026, and would its terms give Russia actual control of Kostyantynivka (part of the 'fortress belt') or freeze lines short of it?
How does ISW typically handle urban capture claims — how long after Russian claims of full control does ISW shade an entire municipality red, and do infiltration zones lag control shading significantly?
What do other prediction markets (Polymarket/Kalshi) price for Russian capture of Kostyantynivka, Kramatorsk, Sloviansk, or a ceasefire in 2026?

Planner reasoning

This is a Polymarket military-territorial question resolving on the ISW map's shading of Kostyantynivka (Donetsk Oblast) by end of 2026. Key drivers are current front-line proximity and the rate of Russian advance toward/into the city, the status of the Pokrovsk-Myrnohrad-Kostyantynivka axis, ISW's mapping conventions (infiltration vs. control), and the probability of a ceasefire/settlement freezing lines. I'll anchor on the Polymarket price, check the ISW resolution source and DeepState, pull recent battlefield reporting, and triangulate with related Polymarket/Kalshi markets on Ukraine territory and ceasefire.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.3s	1	## This Market's Polymarket Data Will Russia capture all of Kostyantynivka by December 31, 2026? - Current price (probability): 29.00% - 7-day price change: -10.50% - 30-day price change: -19.50% - Total volume: $904,429 (USD notional) - Price range: 29.00% - 58.50% - Data points: 90 days
resolution_source	OK	4.9s	1	already_resolved=unclear; matches_criteria=True; last_updated=unknown. The fetched page content did not load any substantive map data or status information about Kostyantynivka's control status; only page titles/headers were returned.
article_search	OK	1.1s	23	Fetched 23 unique articles across 4 queries (lookback=45d). 'Russian forces Kostyantynivka advance': 10 articles \| 'Kostiantynivka Donetsk frontline ISW assessment': 10 articles \| 'Pokrovsk Myrnohrad Kostyantynivka fortress belt offensive': 10 articles \| 'Russia Ukraine ceasefire negotiations Donets
claude_news	OK	34.6s	17	Based on my research, here are the key findings on the Kostyantynivka battlefield situation and related context: - Battle status (ongoing, contested): The Battle of Kostiantynivka has been running since around October 25, 2025, and remains "Ongoing" as of the latest tracking. At the beginning
gdelt_news	OK	152.3s	20	GDELT: 20 articles across 3 queries (lookback=30d). 'Kostiantynivka Russian assault': 10 hits \| 'Kostyantynivka captured': error GDELT rate-limited after retries (429) \| 'Konstantinovka Donetsk offensive': 10 hits
polymarket_related	OK	3.0s	24	Polymarket search over 5 keyword(s), kept 24 matches. keyword 'Kostyantynivka': 5 markets \| keyword 'Kramatorsk': 5 markets \| keyword 'Sloviansk': 4 markets \| keyword 'Druzhkivka': 5 markets \| keyword 'Russia Ukraine ceasefire': 5 markets
kalshi_related	OK	1.9s	2	2 related markets / summaries. keyword 'Ukraine ceasefire': ok \| keyword 'Russia Ukraine': ok \| keyword 'Donetsk': no matches
wikipedia	OK	0.6s	4	Fetched 4 Wikipedia entries (0 missing pages).
code_execution	OK	75.3s	0	## Monte Carlo Model: Russia Fully Captures Kostyantynivka by Dec 31, 2026 Model setup: ~18 months remaining, distance-to-full-capture 7–14 km (city diameter ~9.2 km for 66 km² + approach distance), lognormal monthly advance rate, monthly ceasefire hazard freezing the line permanently. **Histo

3. Evidence Brief Sonnet 5 · 8420 chars

# Current state Kostyantynivka remains contested as of mid-September 2026: Russian forces have infiltrated large parts of the city and hold significant positions, but Ukrainian Defense Forces still control meaningful territory inside the municipality, and ISW/DeepState have not shaded the entire city red. Resolution requires the ENTIRE municipality shaded red (control/advance/gains, not "infiltration") on ISW's map, persisting through one full update cycle — a materially higher bar than "Russia claims capture" or even "mostly infiltrated." # Timeline of key events - 2025-10-25 (confirmed): Battle of Kostiantynivka begins. - 2026-01 (confirmed): Russian assaults launch from Yablunivka toward SW Kostiantynivka via H-20 highway; infiltration toward Illinivka reported by Jan 17, prompting semi-encirclement warning from Ukraine's 28th Mechanized Brigade commander (Wikipedia/claude_news). - 2026-03 (confirmed): Russian monthly territorial gains fall to 133 km², lowest since June 2024 — broad slowdown signal (claude_news). - 2026-06-23 (confirmed): DeepState reports net Russian gains of only ~12 sq mi in prior 4 weeks, down from ~21 sq mi — continued deceleration (claude_news). - 2026-07-04 (reported/disputed): Kremlin's Peskov claims Kostyantynivka "completely taken." DeepState co-founder Pohorilyi calls this premature; city remains under Ukrainian Defense Forces control (english.nv.ua). - 2026-07-29/31 (confirmed): DeepState/Al Jazeera report Russia has "infiltrated most of" Kostiantynivka but not achieved full capture; fighting concentrated between Illinivka and Novodmytrivka. - 2026-08-28 (confirmed): ISW says Russian claims of "pervasive" advances (incl. Gerasimov's) "remain divorced from reality"; most active fighting still around Kostyantynivka per DeepState (CNBC). - 2026-09-01–13 (confirmed): DeepState/GDELT/RightSpeak trackers show 20-23 daily clashes in "Kostiantynivka direction" continuing; city still contested, no full-red shading reported. - 2026-09-05/11 (reported): Witkoff/Kushner-Kremlin talks in Moscow; Putin reiterates demand Ukraine cede all Donetsk Oblast; no ceasefire reached; Zelensky expects war to continue. # Event Will Russia capture the ENTIRE municipality of Kostyantynivka (per ISW map shading) by December 31, 2026? # Outcomes to forecast Yes / No # Kalshi market anchor No kalshi_direct data was returned for this ticker. The Polymarket twin market (identical question/ticker format) currently trades YES at **29.0%**, down from a 30-day high of 58.5% (-19.5% 30d, -10.5% 7d), on $904K volume — a sharp downward re-rating reflecting the slower-than-expected advance since the disputed July "capture" claim. Treat 29% as the best available cross-market consensus anchor in absence of direct Kalshi data. # Resolution source ISW StoryMaps and DeepStateMap pages both returned no usable rendered content (JS-based maps not captured by static fetch); status is "unclear/unknown" per tool. No confirmation the resolution condition is already met — narrative evidence strongly suggests it is NOT (city still contested as of Sept 2026). # Sub-question answers 1. **ISW map status/90-day trend**: Not directly retrievable (map didn't render), but narrative sources confirm partial infiltration, not full red shading, as of Sept 2026; trend is toward deeper but incomplete Russian penetration since Oct 2025. 2. **Distance/pace of advance**: ISW/CDS noted only ~1 km advance over two months in early 2026 on this axis; DeepState confirms monthly gains slowing (133 km² in March, ~12 sq mi in June) — much slower than Bakhmut's pace and far slower than Avdiivka's late collapse. 3. **Pokrovsk/Myrnohrad/Chasiv Yar/Toretsk status**: Pokrovsk and Myrnohrad reported captured "early 2026" after Nov 2025 entry, but Russia failed to capitalize/advance further west since Dec 2025 (Wikipedia). No explicit confirmation Chasiv Yar/Toretsk are fully fallen; Chasiv Yar is cited as the closest analog and remains a slow-grind case (code_execution). 4. **Ceasefire probability/terms**: Polymarket prices ceasefire by Dec 31, 2026 at 22.5%, by Oct 31, 2026 at 7.5%. Kremlin demands full Donetsk Oblast cession (which would include Kostyantynivka); Ukraine resists. No breakthrough as of Sept 2026 talks (Kushner/Witkoff). 5. **ISW lag on capture claims**: Not directly answered by research; general historical pattern (Bakhmut, Avdiivka) shows ISW lags official Russian claims by weeks-to-months and treats "infiltration" separately from "control" — consistent with the market's explicit rule excluding infiltration shading. 6. **Other markets**: Polymarket Kramatorsk-entry 20.5%, Sloviansk-capture 3.5%, Druzhkivka-entry 48.5%, Oleksiievo-Druzhkivka-capture-by-Dec31 21%. All show a steep gradient — Kostyantynivka (fortress-belt gateway) priced meaningfully higher than deeper targets but still below 50%. # Key facts (high-confidence, factual) 1. [Wikipedia] Kostiantynivka pop. collapsed from ~15,000 (Feb 2025) to ~2,800 (early 2026) amid fighting. 2. [Polymarket] This exact market fell from 58.5% to 29% over 30 days. 3. [claude_news/Al Jazeera] Russia's July 2026 "captured" claim was premature per DeepState; fighting persists into September. 4. [Polymarket_related] Sibling markets (Sept 30, Oct 31 2026 deadlines) already resolved/trading near 0-7% YES, confirming no full capture through October. 5. [code_execution Monte Carlo] Blended model estimate: 25-35% probability of full capture by Dec 31, 2026, heavily dependent on advance-rate analog chosen. # Cross-market signals - Kalshi related: No direct Donetsk/Kostyantynivka comparables found; Ukraine election market unrelated. - Polymarket: Twin market 29% YES; related "enter Druzhkivka" (next city west) at 48.5%, implying market believes Druzhkivka entry more likely than Kostyantynivka full capture — consistent with partial encirclement dynamics. - Ceasefire markets: 22.5% by Dec 31, 2026 — a meaningful tail risk that could freeze lines short of full capture (favoring No) or, if terms cede Donetsk Oblast, could paradoxically trigger Yes per market rules on negotiated settlement. # Analyst opinions and speculation - ISW: Russian "pervasive success" narrative from Gerasimov "divorced from reality" (Aug 2026) — skeptical of rapid capture claims. - DeepState: Frames Kostyantynivka as still Ukrainian-controlled despite Russian claims; sees "controlled chaos" infiltration tactics not yet full capture. - Code-execution model: Outcome swings from ~0% to ~90% depending on whether Chasiv Yar (slow-grind, still uncaptured after 18+ months) or Bakhmut/Vuhledar (rapid collapse post-flanking) is the better analog; blended estimate ~25-35%. # Directional lean per outcome - **Yes**: Heavy Russian resource concentration on this axis, semi-encirclement reported since Jan 2026, "gateway to Donbas" priority target, ~3.5 more months of grinding could tip a heavily infiltrated city into full collapse (Bakhmut/Vuhledar-style flank collapse pattern). - **No**: Sharp market repricing down (58.5%→29%) after failed July capture claim; ISW/DeepState confirm continued Ukrainian resistance in Sept 2026; overall Russian advance pace has decelerated markedly (133 km²/mo in March, further slowing by June); Chasiv Yar analog (18+ months, still uncaptured) is most geographically comparable; active ceasefire negotiations create freeze risk; resolution bar (100% shading, sustained) is stringent and historically lags claims significantly. # Gaps / unknowns - No live ISW map data retrieved — cannot confirm current % shaded red vs. grey/infiltration. - No confirmation on Chasiv Yar/Toretsk full-capture status as of Sept 2026. - Exact remaining un-captured area/km inside Kostyantynivka unknown. - Kalshi's own current YES price for this ticker was not returned by kalshi_direct — using Polymarket as best proxy. # Calibration anchors - Polymarket cross-market price (proxy anchor): 29% YES, declining trend. - Sibling Polymarket markets already effectively resolved No through Oct 31, 2026 (7% YES), showing capture has NOT happened yet as of most recent close date. - Code-execution Monte Carlo blended estimate: 25-35% (range 10-55%). - Historical precedent: comparable "fortress belt" cities (Bakhmut ~10mo, Avdiivka ~16mo w/ late collapse, Chasiv Yar 18+mo still incomplete) suggest full urban capture is slow and uncertain within a ~3.5-month remaining window from current infiltration stage.

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

claude-fable-5-1

52% conf

Yes	27%
No	73%

The Polymarket twin trades at 29% YES and has re-rated sharply down (58.5%→29%) after the Kremlin's July 2026 'complete capture' claim proved premature per DeepState, with ISW calling Russian advance claims 'divorced from reality' in late August. Fighting is still active inside and around the city in mid-September with 20+ daily clashes, and the resolution bar—the entire municipality shaded red on ISW's map (excluding infiltration) and sustained through an update cycle—typically lags Russian claims by weeks to months, as at Bakhmut and Avdiivka. The nearest geographic analog, Chasiv Yar, remains incompletely captured after 18+ months, and Russia's overall monthly gains have decelerated markedly, though heavy infiltration and semi-encirclement leave real risk of a late flank-collapse within the ~3.5-month window. Ceasefire risk (~22%) mostly cuts toward No by freezing lines. I land slightly below the anchor given the strict ISW shading requirement and the failed prior capture claim.

claude-fable-5-1

52% conf

Yes	26%
No	74%

The Polymarket twin market trades YES at 29% (down from 58.5% over 30 days), and sibling Oct 31 markets at ~7% confirm the city is far from fully captured as of mid-September 2026. Resolution requires ISW to shade the ENTIRE municipality as controlled (not infiltrated) and persist through an update cycle — a stringent bar that historically lags Russian claims by weeks to months, and ISW/DeepState explicitly rejected the July 'complete capture' claim. Russian advance rates have decelerated sharply (133 km² in March, ~12 sq mi in June), and the Chasiv Yar analog (18+ months, still incomplete) is more geographically comparable than Bakhmut/Vuhledar collapses. With ~3.5 months left, heavy infiltration and semi-encirclement leave a real chance of late collapse, but the strict shading requirement and possible ceasefire freeze tilt me slightly below the market anchor.

claude-fable-5-1

52% conf

Yes	26%
No	74%

Anchor is the Polymarket twin at 29% YES, down sharply from 58.5% after the Kremlin's July 2026 'complete capture' claim was rebutted by DeepState and fighting persisted into September. The resolution bar is stringent — the ENTIRE municipality shaded red (not infiltration) on ISW's map, sustained for a full update cycle — and ISW has historically lagged Russian claims by weeks to months while explicitly separating infiltration from control. Overall Russian advance rates have decelerated markedly (133 km² in March, ~12 sq mi net in June), and the Chasiv Yar-style slow grind is the closest geographic analog, though heavy infiltration and semi-encirclement leave a real Bakhmut/Vuhledar-style collapse tail within the ~3.5-month window. Ceasefire risk (~22%) mostly favors No by freezing lines. I shade slightly below the anchor given the strict shading requirement and downward momentum.

gpt-5.6-sol

68% conf

Yes	27%
No	73%

Partial infiltration and semi-encirclement make eventual collapse plausible, but persistent Ukrainian control and slow advances point toward No within the remaining months. Comparable fortress battles, especially Chasiv Yar, suggest that converting infiltration into complete, sustained ISW control can take much longer, while a ceasefire could freeze the front. Related markets also imply limited prospects for deeper Russian progress, and the strict full-municipality shading requirement creates additional resolution risk. I place Yes slightly below the 29% Polymarket anchor at 27% because the slowing advance and ISW's likely lag behind battlefield claims both favor No.

gpt-5.6-sol

68% conf

Yes	27%
No	73%

Partial infiltration but no confirmed full-red ISW shading points toward No because the resolution requires control of the entire municipality through a full update cycle. The slow advance—about 1 km over two months on this axis, alongside declining territorial gains—makes completion within roughly 3.5 months less likely, while the Chasiv Yar comparison illustrates how long such fighting can persist. Related markets' low probabilities for deeper objectives and the 22.5% ceasefire probability also favor No. I shade slightly below the 29% Polymarket YES anchor to 27% because the stringent mapping rule and likely ISW confirmation lag create additional resolution risk.

6. Final plain mean of 5 draws

27% (58% confidence)

Yes: 27% No: 73%

Mean of 5 draws (0.27, 0.26, 0.26, 0.27, 0.27). The Polymarket twin trades at 29% YES and has re-rated sharply down (58.5%→29%) after the Kremlin's July 2026 'complete capture' claim proved premature per DeepState, with ISW calling Russian advance claims 'divorced from reality' in late August. Fighting is still active inside and around the city in mid-September with 20+ daily clashes, and the resolution bar—the entire municipality shaded red on ISW's map (excluding infiltration) and sustained through an update cycle—typically lags Russian claims by weeks to months, as at Bakhmut and Avdiivka. The nearest geographic analog, Chasiv Yar, remains incompletely captured after 18+ months, and Russia's overall monthly gains have decelerated markedly, though heavy infiltration and semi-encirclement leave real risk of a late flank-collapse within the ~3.5-month window. Ceasefire risk (~22%) mostly cuts toward No by freezing lines. I land slightly below the anchor given the strict ISW shading requirement and the failed prior capture claim.

Pipeline Timing

Total pipeline time: 237.2s

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