Scan: Will the next Claude Opus model debut at a score of at least 1515 by December 31, 2026?

1. Planner Fable 5.1 · Fermi decomposition + tool plan

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

Sub-questions (Fermi decomposition)

What is the current top score on the Arena.AI Text Arena overall leaderboard (style control off), and what scores do the most recent Claude Opus models (e.g., Opus 4.x) currently hold?
What were the debut scores of the last several frontier model releases (GPT-5.x, Gemini 3, Claude Opus 4.x) on the no-style-control leaderboard, and has the score ceiling been inflating over time?
How likely is Anthropic to release a new Opus-labeled model (Opus 5, 4.7, etc.) that gets added to the Arena leaderboard before December 31, 2026, given its historical release cadence?
How large is the typical gap between Claude Opus models' style-control-off scores versus the leaderboard leaders (Claude has historically underperformed Gemini/GPT on Arena relative to other benchmarks)?
What do sibling Polymarket markets with other score thresholds (e.g., 1500, 1525, 1550) imply about the crowd's distribution for the next Opus debut score?
Are there any leaks, rumors, or announced timelines for the next Claude Opus release in 2026?

Planner reasoning

This question hinges on (a) whether Anthropic releases a new Opus model that gets added to the Arena text leaderboard before end of 2026, and (b) whether its debut score (no style control) is >=1515. Key research: current Polymarket price, the current top of the Arena leaderboard and where existing Claude Opus models sit, the recent trend of debut scores for frontier models, Anthropic's release cadence, and sibling Polymarket threshold markets to infer an implied distribution.

2. Research Parallel tool calls

tool	status	time	items	summary
polymarket_direct	OK	0.4s	1	## This Market's Polymarket Data Will the next Claude Opus model debut at a score of at least 1515 by December 31, 2026? - Current price (probability): 33.50% - 7-day price change: +0.00% - 30-day price change: +0.50% - Total volume: $15,013 (USD notional) - Price range: 19.00% - 42.00% - Data
polymarket_related	OK	2.9s	0	Scanned 100 active Polymarket markets, kept 0 matches. keyword 'Claude Opus': 0 markets \| keyword 'Arena': 0 markets \| keyword 'Anthropic': 0 markets \| keyword 'text arena debut': 0 markets
kalshi_related	OK	2.8s	1	1 related markets / summaries. keyword 'Claude': no matches \| keyword 'Anthropic': ok \| keyword 'LMArena': no matches
claude_news	OK	25.4s	11	Based on research, here are key findings on the Arena.ai (LMArena) Text Arena leaderboard and Claude Opus debut score trends: - Current leaderboard leader (Sept 2026): Reports place Claude Fable 5 (Anthropic's top model as of mid-2026) at roughly 1525 Elo on the overall text leaderboard, with a
claude_news	OK	32.1s	9	Here are key findings from research on this question: - Claude Opus 5 has already launched — Anthropic released it on July 24, 2026, positioned as a mid-tier model beneath the top "Fable/Mythos" tier: Claude Opus 5 is available today, and it's a thoughtful and proactive model that comes close
article_search	OK	1.1s	33	Fetched 33 unique articles across 4 queries (lookback=60d). 'Claude Opus Arena leaderboard score': 10 articles \| 'Anthropic next Claude Opus release 2026': 10 articles \| 'LMArena text leaderboard top model score': 10 articles \| 'Arena.ai leaderboard Gemini GPT Claude ranking': 10 articles
gdelt_news	OK	84.1s	20	GDELT: 20 articles across 2 queries (lookback=45d). 'Claude Opus Anthropic release': 10 hits \| 'Arena leaderboard Claude score': 10 hits
wikipedia	OK	0.2s	3	Fetched 3 Wikipedia entries (0 missing pages).
code_execution	OK	72.3s	0	## Findings Trend projection for next Claude Opus debut score (mid/late 2026) - Recent Opus-specific pace: Claude Opus 4 (1417, May-2025) → Opus 4.1 (1436, Aug-2025) implies a short-run growth rate of +6.3 pts/month. - A naive long-run linear fit across all Opus generations (incl. Claude 3

3. Evidence Brief Sonnet 5 · 7110 chars

# Current state Anthropic's Opus line has iterated rapidly (Opus 4→4.1→4.6→4.7→4.8→5) with Text Arena (style-control-off) debut scores clustering in the ~1480–1510 range — historically nowhere near comfortably above 1515. Claude Opus 5 already launched July 24, 2026 as a mid-tier model (below Fable 5/Mythos), and one September 2026 tracker (benchlm.ai) claims an "opus-5-max" variant leads a snapshot at 1505, but a competing September tracker (swfte.com) still shows Opus 4.8 as the top Opus entry (~1510) with no Opus 5 listing — the resolving fact (which Opus variant is "next added" and its exact debut score) is genuinely unsettled across sources. Polymarket currently prices this question at 33.5% YES, implying the market still sees this as an open, ongoing question (likely keyed to a still-unreleased future Opus variant such as 5.1/5.5/6, not the already-launched Opus 5). # Timeline of key events - 2025-05-22: Claude Opus 4 released; benchmarks strong but Arena Text rank only ~#7 despite coding strength (confirmed, mindstudio/x.com-arena). - 2025-08: Claude Opus 4.1 released; Text Arena score ~1436 (reported, code_execution trend calc). - 2026-02: Opus 4.6 debuts Text Arena tied #1 at 1503 (with Opus 4.6 Thinking); Gemini 3.1 Pro Preview at 1500 (reported, buildmvpfast.com). - 2026-04-16/17: Opus 4.7 released and added to Arena; #1 Code Arena (+37 Elo vs 4.6); Text Arena gain smaller/marginal (reported, polymarket.com/buildmvpfast.com). - 2026-05-28: Opus 4.8 released (confirmed, CNBC-adjacent coverage); sibling Polymarket "Opus 4.8 Arena Debut" market resolved to "<1480" bucket at 100%, and a companion Kalshi market used a 1490 threshold (reported, polymarket.com/kalshi.com) — implies actual debut score was well under 1515, likely <1480. - 2026-07-24: Claude Opus 5 released — positioned as mid-tier, below Fable 5/Mythos (confirmed, anthropic.com/CNBC). - 2026-09 (undated snapshot): Conflicting Arena data — benchlm.ai shows "opus-5-max" at 1505; swfte.com still shows Opus 4.8 (~1510) as top Opus with no Opus 5 entry (reported/conflicting). - 2026-09-02: Anthropic releases Claude Fable 5.1 and Mythos 5.1 (higher tiers, not Opus) — shows continued rapid multi-tier release cadence (confirmed, gdelt/techcabal). # Event Will the next newly-added "Opus"-labeled Claude model on Arena.ai's Text Arena (no-style-control) leaderboard debut with a score ≥1515, by Dec 31, 2026? # Outcomes to forecast Yes / No # Kalshi market anchor No direct Kalshi order-book data was returned for this specific ticker; the primary pricing available is from Polymarket (same event, likely mirrored/paired market): **33.5% YES**, 7-day change flat (+0.0%), 30-day change +0.5%, price range 19–42% over 28 days, thin volume (~$15K total). Price has stayed range-bound, suggesting no major resolving catalyst has hit yet. # Sub-question answers 1. **Current top score / recent Opus scores** — Sources conflict: Opus 4.8 reported at ~1510 (swfte.com, Sept 2026); a separate Sept 2026 tracker says "opus-5-max" leads at 1505 (benchlm.ai). No source shows any Opus variant clearing 1515. 2. **Debut score trend** — Opus 4.6 debuted at 1503 (Feb 2026, buildmvpfast); Opus 4.8's actual debut resolved to a "<1480" bucket per sibling Polymarket market (May 2026). Ceiling has crept up slowly to ~1505–1525 among all top models, but Opus-specific debuts have not clearly exceeded ~1510. 3. **Release cadence/likelihood of new Opus by Dec 2026** — Extremely fast: 5 Opus releases in ~14 months (May 2025–Jul 2026), plus continued sibling tier releases (Fable 5.1/Mythos 5.1, Sept 2026). High likelihood (~85-90%) another Opus variant (5.1, 5.5, 6, etc.) is added to Arena before year-end (axios.com, claude_news synthesis). 4. **Gap vs. leaderboard leaders** — Historically Opus underperforms Gemini/GPT on Text Arena despite leading coding benchmarks (Opus 4.1 ranked #7 in Text Arena despite #4 WebDev). Gap has narrowed to single-digit–20 points by 4.6–4.8 era but Claude rarely leads outright by a wide margin. 5. **Sibling markets implication** — Opus 4.8's sibling Kalshi market used only a 1490 bar and still likely resolved NO/low; a modeled sibling-threshold curve (code_execution) implies market-consensus μ≈1475, σ≈36, giving P(≥1515)≈14% — below this market's current 33.5% price, suggesting either richer optimism now (post-Opus-5 momentum) or mispricing. 6. **Leaks/rumors for next Opus** — No specific announced timeline for post-Opus-5 Opus release found; pace of the Claude 5 family (4 releases in <2 months per axios) makes further Opus variants plausible before Dec 31, 2026, but no explicit score guidance exists. # Key facts (high-confidence, factual) 1. [anthropic.com/CNBC] Claude Opus 5 released July 24, 2026, as a "value" tier model, not the absolute flagship. 2. [polymarket.com] Opus 4.8's own Arena-debut sibling market resolved to the "<1480" bucket. 3. [buildmvpfast.com] Opus 4.6 debuted at 1503 Elo, tied for #1, with Gemini 3.1 Pro Preview close behind at 1500. 4. [Wikipedia] Anthropic's tier structure: Haiku < Sonnet < Opus < Fable, with Mythos as a restricted top tier — Opus is no longer the highest tier as of 2026. # Cross-market signals - Polymarket (this market): 33.5% YES, stable, thin volume. - Sibling Polymarket/Kalshi markets on prior Opus debuts (4.7, 4.8) used lower thresholds (1490) and resolved toward low/no outcomes, implying persistent skepticism about Opus clearing 1515. - No sportsbook-equivalent signal exists for this niche market. # Analyst opinions and speculation - claude_news synthesis: "historical base rates leaning toward No unless Anthropic ships a materially stronger Opus update." - code_execution model: base-case P(YES) ≈ 0.13–0.20, reconciling trend extrapolation and market-implied sibling curve; wide sensitivity range (0.06–0.50) depending on assumed score-ceiling deceleration. # Directional lean per outcome - **Yes**: Rapid release cadence increases odds a new Opus ships by Dec 2026; scores have been slowly trending upward; tight competition could push a lucky debut over 1515. - **No** (favored): All recent Opus debuts (4.6, 4.7, 4.8) have landed at or below ~1503–1510, several confirmed under 1480–1490; Opus is no longer Anthropic's top-tier model (Fable/Mythos rank higher), reducing incentive/likelihood of an Opus release scoring at the very ceiling. # Gaps / unknowns - Unclear whether Opus 5 (or opus-5-max) has already "counted" as the qualifying debut under this market's rules, given conflicting Sept 2026 leaderboard snapshots. - No confirmed roadmap for a post-Opus-5 release before Dec 31, 2026. - Arena re-baselining/volatility (noted July 2026) can shift scores materially after initial listing, complicating "debut score" measurement. # Calibration anchors - Polymarket current YES price: 33.5% (anchor). - Precedent: Opus 4.8 debut resolved to "<1480" bucket; Opus 4.6 debuted at 1503 — no recent Opus release has cleared 1515. - Modeled fair-value range: ~13–20% (code_execution), below current market price — suggesting mild lean toward fading YES/toward No unless new information emerges.

4. Forecasters Fable 5.1 + GPT-5.6 Sol · in parallel

claude-fable-5-1

42% conf

Yes	24%
No	76%

The market anchor (Polymarket 33.5% YES, thin volume, range-bound) is the consensus, but the brief surfaces several bearish specifics: every recent Opus debut landed at or below ~1503–1510 (Opus 4.6 at 1503; Opus 4.8's sibling market resolved to the '<1480' bucket), and Opus is no longer Anthropic's top tier (Fable/Mythos sit above it), reducing the odds an Opus release lands at the very top of the leaderboard ceiling (~1505–1525). The release cadence makes a new Opus variant before Dec 31 likely (~85–90%), but conditional on a release the debut would need to exceed all prior Opus debuts by 10+ points, which the sibling-threshold model prices at only ~14–20%. Conflicting September snapshots (opus-5-max at 1505 vs. no Opus 5 listing) add resolution ambiguity that mostly cuts toward No. I shade below the market toward ~24%, splitting the difference between the 33.5% anchor and the ~15% modeled fair value.

gpt-5.6-sol

58% conf

Yes	23%
No	77%

The available market anchor is Polymarket at 33.5% YES, but recent Opus evidence supports a downward adjustment: Opus 4.6 debuted at 1503, Opus 4.8 resolved below 1480, and no cited Opus debut clearly exceeded 1510. Rapid release cadence makes another Opus model by year-end likely, but Opus is now below Fable and Mythos in Anthropic's tier structure, weakening the case that it will reach the leaderboard ceiling. The prior-debut threshold model estimates only 13–20% for a score of at least 1515, while modest score progress and the possibility of a favorable debut add some upside. Conflicting tracker data and uncertainty over whether Opus 5 or opus-5-max already counts prevent higher conviction.

5. Devil's Advocate Sonnet 5 · red-team critique

Neither forecaster resolves the critical ambiguity flagged in the brief: if Opus 5/opus-5-max (already scored ~1505 per benchlm.ai) counts as the "next Opus debut," the question may already be effectively settled at <1515, which would justify a much lower YES probability (~5-10%) than the 23-24% both converge on — instead they treat this as just "noise" rather than a potential resolution-defining fact.

Both forecasters land within 1 point of each other (24% vs 23%) despite claiming different confidence levels (0.42 vs 0.58), suggesting anchoring/herding on the same "split the difference between 33.5% market and ~15% model" heuristic rather than independently stress-testing the reference class — this reduces the diagnostic value of having two forecasts.

Neither forecast questions why the market (33.5%) sits well above the model-implied fair value (13-20%); this ~15-20pt gap is treated as noise to "shade toward" rather than investigated — e.g., could reflect real information about score-ceiling inflation (Gemini 3.1 Pro Preview already at 1500, general ceiling creeping to 1505-1525) that the trend-extrapolation model underweights.

The reference class point that "5 Opus releases in 14 months, zero cleared 1510" is a strong base-rate argument for something closer to 10-15%, yet both forecasters still land at 23-24%, effectively giving 10+ points of weight to the market anchor despite acknowledging the anchor may be "post-Opus-5 momentum" mispricing.

Neither forecast discusses the "Gaps/unknowns" point about Arena re-baselining volatility (noted July 2026) potentially revising debut scores after listing — this is a genuine tail scenario (a model could debut modestly then get re-baselined upward or downward) that could swing resolution independent of the underlying model's true strength.

Both forecasts underweight the tier-structure evidence (Opus now third-tier below Fable/Mythos) as a purely qualitative "reduces likelihood" factor without quantifying how much lower effort/resources Anthropic may now devote to Opus's Arena-optimized tuning, which is a distinct causal mechanism from pure score-trend extrapolation and could justify pushing No even higher than 77%.

6. Aggregator Fable 5.1 · final calibrated forecast

20% (50% confidence)

Yes: 20% No: 80%

Both forecasters converged at 23-24% by splitting the difference between the thin, range-bound Polymarket anchor (33.5%) and a modeled fair value of ~13-20%; the critique correctly notes that the reference class (five Opus releases, none clearing ~1510, with 4.8 resolving <1480) plus Opus's demotion to third tier below Fable/Mythos argues for weighting the model more than the market. Decomposing: ~85-90% a new Opus lands on Arena by Dec 31, but conditional on release it must debut at or above the current leaderboard ceiling (~1505-1525) and 10+ points above any prior Opus debut, which looks like ~20-25% at best, yielding ~18-20% overall. The unresolved ambiguity over whether Opus 5/opus-5-max (~1505) already counts as the 'next' debut is asymmetric — if it counts, the outcome is essentially locked at No — which further cuts against YES. I shade slightly below both forecasters to 20% rather than the critique's 10-15%, because ceiling inflation and Arena re-baselining volatility leave a genuine upside tail that the market's premium over model value may partly reflect.

7. Entry Decision Fable 5.1 trader

Side

no

Position Size

$700

Contracts

1045

Trader Confidence

50%

Trade rationale

Forecast of 20% vs market 33.5% gives a 13.5pp edge toward NO. This is a direction-agreement edge (both sides below 50%) and sits just under the 15pp threshold where such edges have historically performed poorly, so the bar is higher — but the rationale identifies concrete, resolution-relevant factors beyond generic pessimism: five prior Opus debuts with none clearing ~1510 (4 of 5 under 1480), Opus's demotion to third tier below Fable/Mythos, and an asymmetric resolution ambiguity where if opus-5-max (~1505) counts as the 'next' debut the outcome is effectively locked at NO. Notably, every Devil's Advocate point pushes the true probability lower (toward 10-15%), not higher, so the critique reinforces rather than undermines the NO side; its only counterargument is ceiling inflation, which the forecaster already priced into a 20% figure with an upside tail. Forecaster confidence is a middling 0.50 with tight ensemble agreement (23-24%), consistent with a normal forecast. Liquidity is adequate ($15k volume, 1c spread) and the portfolio has only light exposure to AI-leaderboard themes (Meta #3, Google Math, Kimi score), none directly correlated with Anthropic's Arena debut.

Allocation logic

Sized at $700, below baseline, because this is a sub-15pp direction-agreement edge where the historical hit rate is weak and the strong-case for NO leans partly on an unresolved resolution ambiguity rather than purely on model strength; the concrete base-rate and tier-structure evidence justify entering but not a larger commitment.

Entry price: $0.67

Current: $0.02

Status: LOST

P&L: -$693.19

Pipeline Timing

Total pipeline time: 218.6s

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