Anchor on the historical base rate of Anthropic ever holding #1 on the text arena (very low) and the current leaderboard state, then adjust for whether Anthropic ships and submits a new flagship and how fast competitors iterate; combine the four correlated factors via weighted average.
## Cross-Market Signals ### Polymarket - "Will Anthropic have the best AI model at the end of July 2026?" → Yes: 0.99, Volume: $979.8K - "Will Google have the best AI model at the end of July 2026?" → Yes: 0.00, Volume: $827.6K - "US-Iran Final Nuclear Deal by August 13, 2026?" → Yes: 0.02, Volume: $605.6K
1. [sq1 | web_search | STRONG cred 78 | UP | VERY_RECENT] Arena.ai leaderboard snapshot (~July 21-26, 2026) shows claude-fable-5 at #1 overall with 1507±6, ahead of claude-opus-4-6-thinking at 1505±4. 2. [sq1 | web_search | STRONG cred 75 | UP | VERY_RECENT] On the text-specific arena win-rate view, Claude Fable 5 (High) led at 12.72%±2.00%, ahead of GPT 5.6 Sol (xHigh) at 10.12%. 3. [sq1 | web_search | MODERATE cred 70 | NEUTRAL | VERY_RECENT] Text leaderboard reported 7,430,560 votes across 378 models as of Jul 21, 2026, indicating dense competition and frequent model turnover. 4. [sq2 | web_search | STRONG cred 75 | UP | DATED] In late February 2026, Claude Opus 4.6 became the first model to simultaneously hold #1 on LMArena text, code, and search leaderboards. 5. [sq2 | web_search | STRONG cred 72 | UP | DATED] By June 2026 Anthropic held five of the top ten arena spots (Opus 4.6/4.7 variants plus Opus 4.8-thinking), even after Fable 5's temporary withdrawal. 6. [sq2 | code_execution | WEAK cred 30 | DOWN | VERY_RECENT] A stationary base-rate/scenario Monte Carlo model produced ~5-7% probability of Anthropic holding #1 at a future date (90% CI 0.7%-14%). 7. [sq3 | web_search | STRONG cred 75 | UP | RECENT] Anthropic launched Claude Fable 5 on June 9, 2026 (peaking ~1525 ELO) and has shipped Opus 4.6, 4.7, and 4.8 within 2026, showing rapid release cadence. 8. [sq3 | web_search | MODERATE cred 65 | NEUTRAL | RECENT] Claude Fable 5 was suspended worldwide June 12-July 1, 2026 under a US Commerce export-control directive before being restored with a new safety classifier. 9. [sq4 | web_search | MODERATE cred 70 | UP | VERY_RECENT] July 2026 saw competing releases including Grok 4.5 (July 8) and the GPT-5.6 family (Luna, Terra, Sol, July 9), none of which displaced Claude from #1 in the late-July snapshot. 10. [sq4 | web_search | MODERATE cred 60 | NEUTRAL | DATED] An April 2026 snapshot had claude-opus-4-6-thinking at #1, illustrating that the top spot has shifted repeatedly across 2026 among frontier labs. 11. [sq4 | article_search | WEAK cred 70 | NEUTRAL | DATED] Google is aggressively pushing Gemini across Android/Chrome and used Google I/O (May 2026) to showcase its AI roadmap amid investor pressure. 12. [sq1 | article_search | WEAK cred 88 | NEUTRAL | DATED] Anthropic's Claude surged in consumer popularity in 2026 (top iPhone app in March), and its Pentagon blacklisting was blocked by a federal judge in March 2026. ## Cross-Market Signals ### Polymarket - "Will Anthropic have the best AI model at the end of July 2026?" → Yes: 0.99, Volume: $979.8K - "Will Google have the best AI model at the end of July 2026?" → Yes: 0.00, Volume: $827.6K - "US-Iran Final Nuclear Deal by August 13, 2026?" → Yes: 0.02, Volume: $605.6K Information gaps: - No leaderboard reading closer than ~5 weeks before the Aug 31, 2026 resolution date - No data on unreleased Gemini 3.x/GPT-5.7 launches planned for August 2026 - Missing quantified base rate: fraction of days in 2025-2026 an Anthropic model held #1 text - Unclear whether Fable 5's export-control restrictions affect arena eligibility/ranking Key uncertainties: - Whether Google/OpenAI/xAI ship a top-beating model in August 2026 - Typical ELO gap durability — current Claude lead is only ~2-5 points over rivals - Risk of another regulatory suspension pulling Anthropic's top model off the board - Conflict between search-reported current #1 status and the low modeled base rate (~6%)
You are an elite superforecaster using Tetlock-style Fermi decomposition. Estimate each sub-question INDEPENDENTLY, then provide a holistic estimate. The pipeline will mathematically recombine the sub-question estimates — your job is to give the most accurate per-component probabilities.
## Question
Will an Anthropic model be ranked #1 overall on the Chatbot Text Arena Leaderboard at the end of August 2026?
## Description / Resolution Criteria
## Description
Methodology: [Chatbot Arena: An Open Platform for Evaluating LLMs by Human Preference](https://arxiv.org/abs/2403.04132)
`{"format": "bot_tournament_question", "info": {"hash_id": "b66b1e60eaeaf301", "sheet_id": "129"}}`
## Resolution Criteria
This question resolves as **Yes** if a model owned by Anthropic is in the number 1 overall text arena rank (ties count) at the Arena AI [Text Arena Leaderboard](https://arena.ai/leaderboard/text) when accessed by Metaculus on or after August 31, 2026. If this is not the case, this question resolves as **No**.
## Sub-question decomposition
- (w=0.30) Is an Anthropic model currently (as of the research date) ranked #1 or tied for #1 on the LMArena/arena.ai text leaderboard? — Current standing is the single strongest predictor of standing ~9-12 months later; if Anthropic is not near the top now,
- (w=0.20) Has an Anthropic model held the #1 (or tied #1) overall text arena spot at any point in the leaderboard's history (i.e., is there a demonstrated base rate of Anthropic reaching #1)? — Establishes the reference class — Anthropic has historically underperformed on human-preference arena rankings relative
- (w=0.20) Will Anthropic release a new frontier flagship model (e.g., Claude Opus 5 / next-gen) and submit it to the text arena before August 31, 2026? — Anthropic cannot rank #1 without a fresh competitive model listed on the leaderboard; Anthropic has sometimes been slow
- (w=0.30) Will competitors (Google Gemini, OpenAI GPT-series, xAI Grok) fail to hold the top text-arena spot with a newer release in mid/late August 2026? — The top spot is contested and turns over quickly; Anthropic must beat whatever Google/OpenAI/xAI ship in the same window
Combination rule: **weighted_average**
## Synthesized evidence
1. [sq1 | web_search | STRONG cred 78 | UP | VERY_RECENT] Arena.ai leaderboard snapshot (~July 21-26, 2026) shows claude-fable-5 at #1 overall with 1507±6, ahead of claude-opus-4-6-thinking at 1505±4.
2. [sq1 | web_search | STRONG cred 75 | UP | VERY_RECENT] On the text-specific arena win-rate view, Claude Fable 5 (High) led at 12.72%±2.00%, ahead of GPT 5.6 Sol (xHigh) at 10.12%.
3. [sq1 | web_search | MODERATE cred 70 | NEUTRAL | VERY_RECENT] Text leaderboard reported 7,430,560 votes across 378 models as of Jul 21, 2026, indicating dense competition and frequent model turnover.
4. [sq2 | web_search | STRONG cred 75 | UP | DATED] In late February 2026, Claude Opus 4.6 became the first model to simultaneously hold #1 on LMArena text, code, and search leaderboards.
5. [sq2 | web_search | STRONG cred 72 | UP | DATED] By June 2026 Anthropic held five of the top ten arena spots (Opus 4.6/4.7 variants plus Opus 4.8-thinking), even after Fable 5's temporary withdrawal.
6. [sq2 | code_execution | WEAK cred 30 | DOWN | VERY_RECENT] A stationary base-rate/scenario Monte Carlo model produced ~5-7% probability of Anthropic holding #1 at a future date (90% CI 0.7%-14%).
7. [sq3 | web_search | STRONG cred 75 | UP | RECENT] Anthropic launched Claude Fable 5 on June 9, 2026 (peaking ~1525 ELO) and has shipped Opus 4.6, 4.7, and 4.8 within 2026, showing rapid release cadence.
8. [sq3 | web_search | MODERATE cred 65 | NEUTRAL | RECENT] Claude Fable 5 was suspended worldwide June 12-July 1, 2026 under a US Commerce export-control directive before being restored with a new safety classifier.
9. [sq4 | web_search | MODERATE cred 70 | UP | VERY_RECENT] July 2026 saw competing releases including Grok 4.5 (July 8) and the GPT-5.6 family (Luna, Terra, Sol, July 9), none of which displaced Claude from #1 in the late-July snapshot.
10. [sq4 | web_search | MODERATE cred 60 | NEUTRAL | DATED] An April 2026 snapshot had claude-opus-4-6-thinking at #1, illustrating that the top spot has shifted repeatedly across 2026 among frontier labs.
11. [sq4 | article_search | WEAK cred 70 | NEUTRAL | DATED] Google is aggressively pushing Gemini across Android/Chrome and used Google I/O (May 2026) to showcase its AI roadmap amid investor pressure.
12. [sq1 | article_search | WEAK cred 88 | NEUTRAL | DATED] Anthropic's Claude surged in consumer popularity in 2026 (top iPhone app in March), and its Pentagon blacklisting was blocked by a federal judge in March 2026.
## Cross-Market Signals
### Polymarket
- "Will Anthropic have the best AI model at the end of July 2026?" → Yes: 0.99, Volume: $979.8K
- "Will Google have the best AI model at the end of July 2026?" → Yes: 0.00, Volume: $827.6K
- "US-Iran Final Nuclear Deal by August 13, 2026?" → Yes: 0.02, Volume: $605.6K
Information gaps:
- No leaderboard reading closer than ~5 weeks before the Aug 31, 2026 resolution date
- No data on unreleased Gemini 3.x/GPT-5.7 launches planned for August 2026
- Missing quantified base rate: fraction of days in 2025-2026 an Anthropic model held #1 text
- Unclear whether Fable 5's export-control restrictions affect arena eligibility/ranking
Key uncertainties:
- Whether Google/OpenAI/xAI ship a top-beating model in August 2026
- Typical ELO gap durability — current Claude lead is only ~2-5 points over rivals
- Risk of another regulatory suspension pulling Anthropic's top model off the board
- Conflict between search-reported current #1 status and the low modeled base rate (~6%)
## Required pre-forecast walkthrough
Before giving probabilities, walk through these explicitly:
(a) The time left until the question resolves.
(b) The status quo outcome — what happens if nothing changes from today.
(c) A brief scenario that results in NO.
(d) A brief scenario that results in YES.
## Calibration guidance
- **Estimate each sub-question in isolation.** Do not let your answer to one sub-question anchor your answer to another. This is the core of Fermi decomposition — independence forces more careful reasoning per factor.
- **Anchor on the status quo.** Require strong specific evidence to move far from it.
- 0.05 / 0.95 require strong, multi-source evidence. Avoid >0.97 or <0.03 unless the outcome is already settled or near-tautological — overconfident misses are punished heavily by the log score.
- **Anchor on prediction markets.** If liquid market prices (Polymarket / Kalshi) or a community forecast appear in the evidence, treat them as a strong, well-calibrated prior. Your final estimate should rarely sit more than ~15 percentage points from a liquid market on the SAME question — move further only with specific evidence the market lacks.
- **Treat research as fallible, not ground truth.** A single-source or "very recent" claim — especially one the evidence flags as unverified, possibly AI-generated, or low-credibility — must not drive you to near-certainty. When a load-bearing fact is unverified, keep at least 10-15% on the chance it is wrong.
- **Also provide a holistic estimate** — your overall gut feeling about the main question, BEFORE you see the mathematical combination. This serves as a sanity check: if the Fermi result and holistic estimate diverge wildly, something is wrong.
## Output
Return ONLY valid JSON, no markdown fences:
{
"rationale": "<address (a) (b) (c) (d) above — 5-8 sentences total>",
"sub_question_estimates": {
"sq1": <float in [0.01, 0.99]>,
"sq2": <float in [0.01, 0.99]>,
"sq3": <float in [0.01, 0.99]>,
"sq4": <float in [0.01, 0.99]>
},
"holistic_p_yes": <float in [0.01, 0.99] — your overall estimate ignoring the decomposition>,
"what_would_change_my_mind": "<1-2 sentences: what new info would push you above 70% or below 30%>"
}
{
"forecast": {
"combination_logic": "weighted_average",
"evidence_brief": "1. [sq1 | web_search | STRONG cred 78 | UP | VERY_RECENT] Arena.ai leaderboard snapshot (~July 21-26, 2026) shows claude-fable-5 at #1 overall with 1507\u00b16, ahead of claude-opus-4-6-thinking at 1505\u00b14.\n2. [sq1 | web_search | STRONG cred 75 | UP | VERY_RECENT] On the text-specific arena win-rate view, Claude Fable 5 (High) led at 12.72%\u00b12.00%, ahead of GPT 5.6 Sol (xHigh) at 10.12%.\n3. [sq1 | web_search | MODERATE cred 70 | NEUTRAL | VERY_RECENT] Text leaderboard reported 7,430,560 votes across 378 models as of Jul 21, 2026, indicating dense competition and frequent model turnover.\n4. [sq2 | web_search | STRONG cred 75 | UP | DATED] In late February 2026, Claude Opus 4.6 became the first model to simultaneously hold #1 on LMArena text, code, and search leaderboards.\n5. [sq2 | web_search | STRONG cred 72 | UP | DATED] By June 2026 Anthropic held five of the top ten arena spots (Opus 4.6/4.7 variants plus Opus 4.8-thinking), even after Fable 5\u0027s temporary withdrawal.\n6. [sq2 | code_execution | WEAK cred 30 | DOWN | VERY_RECENT] A stationary base-rate/scenario Monte Carlo model produced ~5-7% probability of Anthropic holding #1 at a future date (90% CI 0.7%-14%).\n7. [sq3 | web_search | STRONG cred 75 | UP | RECENT] Anthropic launched Claude Fable 5 on June 9, 2026 (peaking ~1525 ELO) and has shipped Opus 4.6, 4.7, and 4.8 within 2026, showing rapid release cadence.\n8. [sq3 | web_search | MODERATE cred 65 | NEUTRAL | RECENT] Claude Fable 5 was suspended worldwide June 12-July 1, 2026 under a US Commerce export-control directive before being restored with a new safety classifier.\n9. [sq4 | web_search | MODERATE cred 70 | UP | VERY_RECENT] July 2026 saw competing releases including Grok 4.5 (July 8) and the GPT-5.6 family (Luna, Terra, Sol, July 9), none of which displaced Claude from #1 in the late-July snapshot.\n10. [sq4 | web_search | MODERATE cred 60 | NEUTRAL | DATED] An April 2026 snapshot had claude-opus-4-6-thinking at #1, illustrating that the top spot has shifted repeatedly across 2026 among frontier labs.\n11. [sq4 | article_search | WEAK cred 70 | NEUTRAL | DATED] Google is aggressively pushing Gemini across Android/Chrome and used Google I/O (May 2026) to showcase its AI roadmap amid investor pressure.\n12. [sq1 | article_search | WEAK cred 88 | NEUTRAL | DATED] Anthropic\u0027s Claude surged in consumer popularity in 2026 (top iPhone app in March), and its Pentagon blacklisting was blocked by a federal judge in March 2026.\n\n## Cross-Market Signals\n\n### Polymarket\n- \"Will Anthropic have the best AI model at the end of July 2026?\" \u2192 Yes: 0.99, Volume: $979.8K\n- \"Will Google have the best AI model at the end of July 2026?\" \u2192 Yes: 0.00, Volume: $827.6K\n- \"US-Iran Final Nuclear Deal by August 13, 2026?\" \u2192 Yes: 0.02, Volume: $605.6K\n\nInformation gaps:\n - No leaderboard reading closer than ~5 weeks before the Aug 31, 2026 resolution date\n - No data on unreleased Gemini 3.x/GPT-5.7 launches planned for August 2026\n - Missing quantified base rate: fraction of days in 2025-2026 an Anthropic model held #1 text\n - Unclear whether Fable 5\u0027s export-control restrictions affect arena eligibility/ranking\n\nKey uncertainties:\n - Whether Google/OpenAI/xAI ship a top-beating model in August 2026\n - Typical ELO gap durability \u2014 current Claude lead is only ~2-5 points over rivals\n - Risk of another regulatory suspension pulling Anthropic\u0027s top model off the board\n - Conflict between search-reported current #1 status and the low modeled base rate (~6%)",
"forecast_prompt": "You are an elite superforecaster using Tetlock-style Fermi decomposition. Estimate each sub-question INDEPENDENTLY, then provide a holistic estimate. The pipeline will mathematically recombine the sub-question estimates \u2014 your job is to give the most accurate per-component probabilities.\n\n## Question\nWill an Anthropic model be ranked #1 overall on the Chatbot Text Arena Leaderboard at the end of August 2026?\n\n## Description / Resolution Criteria\n## Description\nMethodology: [Chatbot Arena: An Open Platform for Evaluating LLMs by Human Preference](https://arxiv.org/abs/2403.04132)\n\n`{\"format\": \"bot_tournament_question\", \"info\": {\"hash_id\": \"b66b1e60eaeaf301\", \"sheet_id\": \"129\"}}`\n\n## Resolution Criteria\nThis question resolves as **Yes** if a model owned by Anthropic is in the number 1 overall text arena rank (ties count) at the Arena AI [Text Arena Leaderboard](https://arena.ai/leaderboard/text) when accessed by Metaculus on or after August 31, 2026. If this is not the case, this question resolves as **No**.\n\n## Sub-question decomposition\n- (w=0.30) Is an Anthropic model currently (as of the research date) ranked #1 or tied for #1 on the LMArena/arena.ai text leaderboard? \u2014 Current standing is the single strongest predictor of standing ~9-12 months later; if Anthropic is not near the top now,\n- (w=0.20) Has an Anthropic model held the #1 (or tied #1) overall text arena spot at any point in the leaderboard\u0027s history (i.e., is there a demonstrated base rate of Anthropic reaching #1)? \u2014 Establishes the reference class \u2014 Anthropic has historically underperformed on human-preference arena rankings relative \n- (w=0.20) Will Anthropic release a new frontier flagship model (e.g., Claude Opus 5 / next-gen) and submit it to the text arena before August 31, 2026? \u2014 Anthropic cannot rank #1 without a fresh competitive model listed on the leaderboard; Anthropic has sometimes been slow \n- (w=0.30) Will competitors (Google Gemini, OpenAI GPT-series, xAI Grok) fail to hold the top text-arena spot with a newer release in mid/late August 2026? \u2014 The top spot is contested and turns over quickly; Anthropic must beat whatever Google/OpenAI/xAI ship in the same window\n\nCombination rule: **weighted_average**\n\n## Synthesized evidence\n1. [sq1 | web_search | STRONG cred 78 | UP | VERY_RECENT] Arena.ai leaderboard snapshot (~July 21-26, 2026) shows claude-fable-5 at #1 overall with 1507\u00b16, ahead of claude-opus-4-6-thinking at 1505\u00b14.\n2. [sq1 | web_search | STRONG cred 75 | UP | VERY_RECENT] On the text-specific arena win-rate view, Claude Fable 5 (High) led at 12.72%\u00b12.00%, ahead of GPT 5.6 Sol (xHigh) at 10.12%.\n3. [sq1 | web_search | MODERATE cred 70 | NEUTRAL | VERY_RECENT] Text leaderboard reported 7,430,560 votes across 378 models as of Jul 21, 2026, indicating dense competition and frequent model turnover.\n4. [sq2 | web_search | STRONG cred 75 | UP | DATED] In late February 2026, Claude Opus 4.6 became the first model to simultaneously hold #1 on LMArena text, code, and search leaderboards.\n5. [sq2 | web_search | STRONG cred 72 | UP | DATED] By June 2026 Anthropic held five of the top ten arena spots (Opus 4.6/4.7 variants plus Opus 4.8-thinking), even after Fable 5\u0027s temporary withdrawal.\n6. [sq2 | code_execution | WEAK cred 30 | DOWN | VERY_RECENT] A stationary base-rate/scenario Monte Carlo model produced ~5-7% probability of Anthropic holding #1 at a future date (90% CI 0.7%-14%).\n7. [sq3 | web_search | STRONG cred 75 | UP | RECENT] Anthropic launched Claude Fable 5 on June 9, 2026 (peaking ~1525 ELO) and has shipped Opus 4.6, 4.7, and 4.8 within 2026, showing rapid release cadence.\n8. [sq3 | web_search | MODERATE cred 65 | NEUTRAL | RECENT] Claude Fable 5 was suspended worldwide June 12-July 1, 2026 under a US Commerce export-control directive before being restored with a new safety classifier.\n9. [sq4 | web_search | MODERATE cred 70 | UP | VERY_RECENT] July 2026 saw competing releases including Grok 4.5 (July 8) and the GPT-5.6 family (Luna, Terra, Sol, July 9), none of which displaced Claude from #1 in the late-July snapshot.\n10. [sq4 | web_search | MODERATE cred 60 | NEUTRAL | DATED] An April 2026 snapshot had claude-opus-4-6-thinking at #1, illustrating that the top spot has shifted repeatedly across 2026 among frontier labs.\n11. [sq4 | article_search | WEAK cred 70 | NEUTRAL | DATED] Google is aggressively pushing Gemini across Android/Chrome and used Google I/O (May 2026) to showcase its AI roadmap amid investor pressure.\n12. [sq1 | article_search | WEAK cred 88 | NEUTRAL | DATED] Anthropic\u0027s Claude surged in consumer popularity in 2026 (top iPhone app in March), and its Pentagon blacklisting was blocked by a federal judge in March 2026.\n\n## Cross-Market Signals\n\n### Polymarket\n- \"Will Anthropic have the best AI model at the end of July 2026?\" \u2192 Yes: 0.99, Volume: $979.8K\n- \"Will Google have the best AI model at the end of July 2026?\" \u2192 Yes: 0.00, Volume: $827.6K\n- \"US-Iran Final Nuclear Deal by August 13, 2026?\" \u2192 Yes: 0.02, Volume: $605.6K\n\nInformation gaps:\n - No leaderboard reading closer than ~5 weeks before the Aug 31, 2026 resolution date\n - No data on unreleased Gemini 3.x/GPT-5.7 launches planned for August 2026\n - Missing quantified base rate: fraction of days in 2025-2026 an Anthropic model held #1 text\n - Unclear whether Fable 5\u0027s export-control restrictions affect arena eligibility/ranking\n\nKey uncertainties:\n - Whether Google/OpenAI/xAI ship a top-beating model in August 2026\n - Typical ELO gap durability \u2014 current Claude lead is only ~2-5 points over rivals\n - Risk of another regulatory suspension pulling Anthropic\u0027s top model off the board\n - Conflict between search-reported current #1 status and the low modeled base rate (~6%)\n\n## Required pre-forecast walkthrough\n\nBefore giving probabilities, walk through these explicitly:\n (a) The time left until the question resolves.\n (b) The status quo outcome \u2014 what happens if nothing changes from today.\n (c) A brief scenario that results in NO.\n (d) A brief scenario that results in YES.\n\n## Calibration guidance\n\n- **Estimate each sub-question in isolation.** Do not let your answer to one sub-question anchor your answer to another. This is the core of Fermi decomposition \u2014 independence forces more careful reasoning per factor.\n- **Anchor on the status quo.** Require strong specific evidence to move far from it.\n- 0.05 / 0.95 require strong, multi-source evidence. Avoid \u003e0.97 or \u003c0.03 unless the outcome is already settled or near-tautological \u2014 overconfident misses are punished heavily by the log score.\n- **Anchor on prediction markets.** If liquid market prices (Polymarket / Kalshi) or a community forecast appear in the evidence, treat them as a strong, well-calibrated prior. Your final estimate should rarely sit more than ~15 percentage points from a liquid market on the SAME question \u2014 move further only with specific evidence the market lacks.\n- **Treat research as fallible, not ground truth.** A single-source or \"very recent\" claim \u2014 especially one the evidence flags as unverified, possibly AI-generated, or low-credibility \u2014 must not drive you to near-certainty. When a load-bearing fact is unverified, keep at least 10-15% on the chance it is wrong.\n- **Also provide a holistic estimate** \u2014 your overall gut feeling about the main question, BEFORE you see the mathematical combination. This serves as a sanity check: if the Fermi result and holistic estimate diverge wildly, something is wrong.\n\n## Output\n\nReturn ONLY valid JSON, no markdown fences:\n\n{\n \"rationale\": \"\u003caddress (a) (b) (c) (d) above \u2014 5-8 sentences total\u003e\",\n \"sub_question_estimates\": {\n \"sq1\": \u003cfloat in [0.01, 0.99]\u003e,\n \"sq2\": \u003cfloat in [0.01, 0.99]\u003e,\n \"sq3\": \u003cfloat in [0.01, 0.99]\u003e,\n \"sq4\": \u003cfloat in [0.01, 0.99]\u003e\n },\n \"holistic_p_yes\": \u003cfloat in [0.01, 0.99] \u2014 your overall estimate ignoring the decomposition\u003e,\n \"what_would_change_my_mind\": \"\u003c1-2 sentences: what new info would push you above 70% or below 30%\u003e\"\n}\n",
"holistic_p_yes": 0.78,
"models": [
"opus"
],
"p_yes": 0.8292,
"rationale": "(a) Roughly five weeks remain between the latest leaderboard snapshot (~July 21-26, 2026) and the Aug 31, 2026 resolution check. (b) Status quo: Anthropic\u0027s claude-fable-5 sits at #1 overall (1507\u00b16) with claude-opus-4-6-thinking right behind at 1505, and Anthropic occupies several top-10 slots; if nothing changes, this resolves Yes, and a liquid Polymarket contract on essentially the same premise prices Anthropic \u0027best model\u0027 at ~0.99 for end of July. (c) NO scenario: Google ships a Gemini 3.x or OpenAI a GPT-5.7 in August that leaps 10-20 ELO past a lead that is currently only ~2-5 points over the field, or another export-control/regulatory suspension pulls Fable 5 off the board and Anthropic\u0027s remaining models fall a couple points short; the top spot has changed hands repeatedly across 2026. (d) YES scenario: no competitor ships a step-change model in August, or Anthropic itself ships another Opus/Fable increment (its cadence in 2026 has been ~one flagship every 6-10 weeks), preserving or extending the lead through Aug 31. Weighing a durable multi-month pattern of Anthropic dominance in 2026 against a thin ELO margin and a known August release risk from Google/OpenAI, I land in the mid-to-high 70s. The one dissonant input is a weak Monte Carlo stationary base-rate model at ~6%, which clearly ignores the actual current standing and should be heavily discounted, though I retain ~10% weight on the possibility the very-recent leaderboard readings are mis-scraped or misinterpreted.",
"sub_question_estimates": {
"sq1": 0.91,
"sq2": 0.95,
"sq3": 0.93,
"sq4": 0.71
},
"what_would_change_my_mind": "A confirmed August 2026 Gemini 3.x/GPT-5.7 launch topping the arena, or a renewed regulatory suspension of Anthropic\u0027s top model, would push me below 30%; a late-August leaderboard snapshot still showing Claude #1 with a \u003e15 ELO cushion would push me above 90%."
},
"plan": {
"combination_logic": "weighted_average",
"domain": "tech",
"n_sub_qs": 4,
"n_tools": 4,
"reasoning_approach": "Anchor on the historical base rate of Anthropic ever holding #1 on the text arena (very low) and the current leaderboard state, then adjust for whether Anthropic ships and submits a new flagship and how fast competitors iterate; combine the four correlated factors via weighted average.",
"sub_questions": [
{
"id": "sq1",
"question": "Is an Anthropic model currently (as of the research date) ranked #1 or tied for #1 on the LMArena/arena.ai text leaderboard?",
"rationale": "Current standing is the single strongest predictor of standing ~9-12 months later; if Anthropic is not near the top now, it must overtake incumbents.",
"weight": 0.3
},
{
"id": "sq2",
"question": "Has an Anthropic model held the #1 (or tied #1) overall text arena spot at any point in the leaderboard\u0027s history (i.e., is there a demonstrated base rate of Anthropic reaching #1)?",
"rationale": "Establishes the reference class \u2014 Anthropic has historically underperformed on human-preference arena rankings relative to benchmarks, since Google/OpenAI/xAI optimize more for arena-style preference.",
"weight": 0.2
},
{
"id": "sq3",
"question": "Will Anthropic release a new frontier flagship model (e.g., Claude Opus 5 / next-gen) and submit it to the text arena before August 31, 2026?",
"rationale": "Anthropic cannot rank #1 without a fresh competitive model listed on the leaderboard; Anthropic has sometimes been slow or absent in arena submissions.",
"weight": 0.2
},
{
"id": "sq4",
"question": "Will competitors (Google Gemini, OpenAI GPT-series, xAI Grok) fail to hold the top text-arena spot with a newer release in mid/late August 2026?",
"rationale": "The top spot is contested and turns over quickly; Anthropic must beat whatever Google/OpenAI/xAI ship in the same window, and Google has dominated recent leaderboard cycles.",
"weight": 0.3
}
],
"tool_requests": [
{
"parameters": {
"brief": "Determine the current top 10 of the LMArena / arena.ai Text Arena leaderboard (overall text rank): which models and organizations occupy rank #1 and ties, current Elo/score gaps, and how long the current leader has held #1. Also find the full history of which organizations have held #1 on the text arena (Google Gemini, OpenAI, xAI, Anthropic) over the past 24 months, and whether any Anthropic Claude model has ever been #1 or tied #1.",
"max_searches": 5,
"question_title": "Will an Anthropic model be ranked #1 overall on the Chatbot Text Arena Leaderboard at the end of August 2026?"
},
"target_sub_questions": [
"sq1",
"sq2",
"sq4"
],
"tool_name": "claude_news"
},
{
"parameters": {
"queries": [
"arena.ai text leaderboard rank 1 model today",
"LMArena leaderboard top model Anthropic Claude rank",
"Anthropic next flagship model Claude Opus release 2026"
]
},
"target_sub_questions": [
"sq1",
"sq3"
],
"tool_name": "web_search"
},
{
"parameters": {
"lookback_days": 180,
"queries": [
"Anthropic Claude new model release frontier",
"LMArena leaderboard top spot Gemini GPT Grok",
"Chatbot Arena Elo ranking new leader"
]
},
"target_sub_questions": [
"sq3",
"sq4"
],
"tool_name": "article_search"
},
{
"parameters": {
"code": "import numpy as np\n# Base-rate model: estimate probability Anthropic holds #1 (ties count) on a given future date.\n# Inputs: historical share of leaderboard-days each org held #1 over ~24 months.\n# Placeholder priors to be updated with research findings.\nshares = {\u0027Google\u0027:0.55,\u0027OpenAI\u0027:0.25,\u0027xAI\u0027:0.12,\u0027Anthropic\u0027:0.03,\u0027Other\u0027:0.05}\n# Markov-ish: probability leader at t+9months is Anthropic ~ stationary share, adjusted upward for tie allowance\ntie_bonus = 1.6\np_base = shares[\u0027Anthropic\u0027]*tie_bonus\n# Scenario mix: (a) Anthropic ships arena-optimized flagship (p=0.6) -\u003e conditional prob of #1 0.10\n# (b) no such push -\u003e conditional prob 0.02\np = 0.6*0.10 + 0.4*0.02\nprint(\u0027stationary base rate w/ tie bonus:\u0027, round(p_base,4))\nprint(\u0027scenario-mix estimate:\u0027, round(p,4))\n# Monte Carlo sensitivity\nrng=np.random.default_rng(0)\nsims=rng.beta(1.5,25,200000) # skeptical prior on Anthropic #1\nprint(\u0027MC mean:\u0027, round(sims.mean(),4), \u002790% CI:\u0027, np.round(np.percentile(sims,[5,95]),4))",
"description": "Base-rate and scenario-mix estimate of Anthropic holding #1 on the text arena at a future date."
},
"target_sub_questions": [
"sq2",
"sq4"
],
"tool_name": "code_execution"
}
]
},
"question": {
"close_time": "2026-07-26T12:00:00Z",
"description": "## Description\nMethodology: [Chatbot Arena: An Open Platform for Evaluating LLMs by Human Preference](https://arxiv.org/abs/2403.04132)\n\n`{\"format\": \"bot_tournament_question\", \"info\": {\"hash_id\": \"b66b1e60eaeaf301\", \"sheet_id\": \"129\"}}`\n\n## Resolution Criteria\nThis question resolves as **Yes** if a model owned by Anthropic is in the number 1 overall text arena rank (ties count) at the Arena AI [Text Arena Leaderboard](https://arena.ai/leaderboard/text) when accessed by Metaculus on or after August 31, 2026. If this is not the case, this question resolves as **No**.",
"question_type": "binary",
"title": "Will an Anthropic model be ranked #1 overall on the Chatbot Text Arena Leaderboard at the end of August 2026?"
},
"research": {
"cross_market_brief": "## Cross-Market Signals\n\n### Polymarket\n- \"Will Anthropic have the best AI model at the end of July 2026?\" \u2192 Yes: 0.99, Volume: $979.8K\n- \"Will Google have the best AI model at the end of July 2026?\" \u2192 Yes: 0.00, Volume: $827.6K\n- \"US-Iran Final Nuclear Deal by August 13, 2026?\" \u2192 Yes: 0.02, Volume: $605.6K",
"errors": [],
"has_cross_market": true,
"n_errors": 0,
"n_tools": 4,
"tools": [
{
"elapsed_s": 34.99,
"error": null,
"success": true,
"summary": "15 citations",
"tool_name": "claude_news"
},
{
"elapsed_s": 27.33,
"error": null,
"success": true,
"summary": "0 results",
"tool_name": "web_search"
},
{
"elapsed_s": 0.7,
"error": null,
"success": true,
"summary": "28 articles",
"tool_name": "article_search"
},
{
"elapsed_s": 0.17,
"error": null,
"success": true,
"summary": "Base-rate and scenario-mix estimate of Anthropic holding #1 ",
"tool_name": "code_execution"
}
]
},
"synthesis": {
"evidence": [
{
"claim": "Arena.ai leaderboard snapshot (~July 21-26, 2026) shows claude-fable-5 at #1 overall with 1507\u00b16, ahead of claude-opus-4-6-thinking at 1505\u00b14.",
"credibility": 78,
"direction": "UP",
"priced_in": true,
"recency": "VERY_RECENT",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq1"
},
{
"claim": "On the text-specific arena win-rate view, Claude Fable 5 (High) led at 12.72%\u00b12.00%, ahead of GPT 5.6 Sol (xHigh) at 10.12%.",
"credibility": 75,
"direction": "UP",
"priced_in": true,
"recency": "VERY_RECENT",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq1"
},
{
"claim": "Text leaderboard reported 7,430,560 votes across 378 models as of Jul 21, 2026, indicating dense competition and frequent model turnover.",
"credibility": 70,
"direction": "NEUTRAL",
"priced_in": true,
"recency": "VERY_RECENT",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq1"
},
{
"claim": "In late February 2026, Claude Opus 4.6 became the first model to simultaneously hold #1 on LMArena text, code, and search leaderboards.",
"credibility": 75,
"direction": "UP",
"priced_in": true,
"recency": "DATED",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq2"
},
{
"claim": "By June 2026 Anthropic held five of the top ten arena spots (Opus 4.6/4.7 variants plus Opus 4.8-thinking), even after Fable 5\u0027s temporary withdrawal.",
"credibility": 72,
"direction": "UP",
"priced_in": true,
"recency": "DATED",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq2"
},
{
"claim": "A stationary base-rate/scenario Monte Carlo model produced ~5-7% probability of Anthropic holding #1 at a future date (90% CI 0.7%-14%).",
"credibility": 30,
"direction": "DOWN",
"priced_in": false,
"recency": "VERY_RECENT",
"source": "code_execution",
"strength": "WEAK",
"sub_question_id": "sq2"
},
{
"claim": "Anthropic launched Claude Fable 5 on June 9, 2026 (peaking ~1525 ELO) and has shipped Opus 4.6, 4.7, and 4.8 within 2026, showing rapid release cadence.",
"credibility": 75,
"direction": "UP",
"priced_in": true,
"recency": "RECENT",
"source": "web_search",
"strength": "STRONG",
"sub_question_id": "sq3"
},
{
"claim": "Claude Fable 5 was suspended worldwide June 12-July 1, 2026 under a US Commerce export-control directive before being restored with a new safety classifier.",
"credibility": 65,
"direction": "NEUTRAL",
"priced_in": true,
"recency": "RECENT",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq3"
},
{
"claim": "July 2026 saw competing releases including Grok 4.5 (July 8) and the GPT-5.6 family (Luna, Terra, Sol, July 9), none of which displaced Claude from #1 in the late-July snapshot.",
"credibility": 70,
"direction": "UP",
"priced_in": true,
"recency": "VERY_RECENT",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq4"
},
{
"claim": "An April 2026 snapshot had claude-opus-4-6-thinking at #1, illustrating that the top spot has shifted repeatedly across 2026 among frontier labs.",
"credibility": 60,
"direction": "NEUTRAL",
"priced_in": true,
"recency": "DATED",
"source": "web_search",
"strength": "MODERATE",
"sub_question_id": "sq4"
},
{
"claim": "Google is aggressively pushing Gemini across Android/Chrome and used Google I/O (May 2026) to showcase its AI roadmap amid investor pressure.",
"credibility": 70,
"direction": "NEUTRAL",
"priced_in": true,
"recency": "DATED",
"source": "article_search",
"strength": "WEAK",
"sub_question_id": "sq4"
},
{
"claim": "Anthropic\u0027s Claude surged in consumer popularity in 2026 (top iPhone app in March), and its Pentagon blacklisting was blocked by a federal judge in March 2026.",
"credibility": 88,
"direction": "NEUTRAL",
"priced_in": true,
"recency": "DATED",
"source": "article_search",
"strength": "WEAK",
"sub_question_id": "sq1"
}
],
"information_gaps": [
"No leaderboard reading closer than ~5 weeks before the Aug 31, 2026 resolution date",
"No data on unreleased Gemini 3.x/GPT-5.7 launches planned for August 2026",
"Missing quantified base rate: fraction of days in 2025-2026 an Anthropic model held #1 text",
"Unclear whether Fable 5\u0027s export-control restrictions affect arena eligibility/ranking"
],
"key_uncertainties": [
"Whether Google/OpenAI/xAI ship a top-beating model in August 2026",
"Typical ELO gap durability \u2014 current Claude lead is only ~2-5 points over rivals",
"Risk of another regulatory suspension pulling Anthropic\u0027s top model off the board",
"Conflict between search-reported current #1 status and the low modeled base rate (~6%)"
],
"n_evidence": 12
},
"timings": {
"forecast": 22.52,
"plan": 29.25,
"research": 34.99,
"synthesis": 27.68
}
}