Anthropic’s September 1, 2026 release of Claude Mythos 5.1 and the closely related Fable 5.1 established new HLE leaderboard highs of 59.1–65 percent through targeted gains in cybersecurity, biology, and tool-augmented reasoning. These results, verified on the official CAIS/Scale AI board, outpace OpenAI’s GPT-6 Astra at 54.7 percent and other frontier entries clustered in the mid-40s, reinforcing trader expectations that the next Mythos-class model will clear 50–55 percent thresholds on debut. The benchmark’s 2,500 expert-authored questions across mathematics, physics, and multimodal tasks continue to resist saturation, keeping outcomes sensitive to any new Anthropic launch before year-end amid competitive pressure from Google DeepMind and Meta.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated$21,881 Vol.
Dec 31, 2026
45%+
99%
50%+
100%
55%+
2%
60%+
2%
$21,881 Vol.
45%+
$2,431 Vol.
99%
50%+
$8,707 Vol.
100%
55%+
$5,005 Vol.
2%
60%+
$5,739 Vol.
2%
This market will resolve to "Yes" if the next Anthropic Mythos-class model added to the Humanity's Last Exam results at https://agi.safe.ai/ has an HLE Accuracy of at least the specified percentage at 12:00 PM ET on the calendar date following the date on which it first appears on the site. Otherwise, this market will resolve to "No".
Any model whose official name includes "Mythos," or "Fable" (e.g., Claude Fable 5.1 or Claude Fable 6), or that Anthropic officially describes as a "Mythos-class" model or similar, will qualify for this market's resolution. Anthropic's other model tiers, such as Opus, Sonnet, or Haiku, will not qualify.
The percentage displayed as "HLE Accuracy" for the model in its result card on the "AI Progress on Humanity's Last Exam" chart at https://agi.safe.ai/ will be used to resolve this market. This market will resolve solely based on the displayed HLE Accuracy, regardless of the model's Calibration Error, chart position, other configuration scores, or any underlying granular or unrounded data presented elsewhere.
If multiple qualifying models are added to the Humanity's Last Exam results on the same calendar date (ET), the model with the highest HLE Accuracy will be used for resolution. Models added to the results on the calendar date following the initial qualifying model's first appearance will not be considered. If a model is first added to the Humanity's Last Exam results but is subsequently removed and not re-added, such that it is not displayed on the site at 12:00 PM ET on the calendar date following its first appearance, its appearance will not qualify as added to the Humanity's Last Exam results.
A qualifying model must be newly added to the Humanity's Last Exam results at https://agi.safe.ai/. Whether the model was previously released, publicly accessible, in beta, or otherwise available before appearing on the site is irrelevant for this market.
The resolution source for this market is the official Humanity's Last Exam website found at https://agi.safe.ai/. If this resolution source is unavailable at 12:00 PM ET on the calendar date following the date on which the qualifying model first appears on the site, this market will resolve based on the first subsequent instance at which the model's HLE Accuracy becomes available on the site. If it remains unavailable through the end of the seventh day after the qualifying model first appears on the site or if no qualifying model is added by December 31, 2026, 11:59 PM ET, this market will resolve to "No".Anthropic’s September 1, 2026 release of Claude Mythos 5.1 and the closely related Fable 5.1 established new HLE leaderboard highs of 59.1–65 percent through targeted gains in cybersecurity, biology, and tool-augmented reasoning. These results, verified on the official CAIS/Scale AI board, outpace OpenAI’s GPT-6 Astra at 54.7 percent and other frontier entries clustered in the mid-40s, reinforcing trader expectations that the next Mythos-class model will clear 50–55 percent thresholds on debut. The benchmark’s 2,500 expert-authored questions across mathematics, physics, and multimodal tasks continue to resist saturation, keeping outcomes sensitive to any new Anthropic launch before year-end amid competitive pressure from Google DeepMind and Meta.
This market will resolve to "Yes" if the next Anthropic Mythos-class model added to the Humanity's Last Exam results at https://agi.safe.ai/ has an HLE Accuracy of at least the specified percentage at 12:00 PM ET on the calendar date following the date on which it first appears on the site. Otherwise, this market will resolve to "No".
Any model whose official name includes "Mythos," or "Fable" (e.g., Claude Fable 5.1 or Claude Fable 6), or that Anthropic officially describes as a "Mythos-class" model or similar, will qualify for this market's resolution. Anthropic's other model tiers, such as Opus, Sonnet, or Haiku, will not qualify.
The percentage displayed as "HLE Accuracy" for the model in its result card on the "AI Progress on Humanity's Last Exam" chart at https://agi.safe.ai/ will be used to resolve this market. This market will resolve solely based on the displayed HLE Accuracy, regardless of the model's Calibration Error, chart position, other configuration scores, or any underlying granular or unrounded data presented elsewhere.
If multiple qualifying models are added to the Humanity's Last Exam results on the same calendar date (ET), the model with the highest HLE Accuracy will be used for resolution. Models added to the results on the calendar date following the initial qualifying model's first appearance will not be considered. If a model is first added to the Humanity's Last Exam results but is subsequently removed and not re-added, such that it is not displayed on the site at 12:00 PM ET on the calendar date following its first appearance, its appearance will not qualify as added to the Humanity's Last Exam results.
A qualifying model must be newly added to the Humanity's Last Exam results at https://agi.safe.ai/. Whether the model was previously released, publicly accessible, in beta, or otherwise available before appearing on the site is irrelevant for this market.
The resolution source for this market is the official Humanity's Last Exam website found at https://agi.safe.ai/. If this resolution source is unavailable at 12:00 PM ET on the calendar date following the date on which the qualifying model first appears on the site, this market will resolve based on the first subsequent instance at which the model's HLE Accuracy becomes available on the site. If it remains unavailable through the end of the seventh day after the qualifying model first appears on the site or if no qualifying model is added by December 31, 2026, 11:59 PM ET, this market will resolve to "No".
Any model whose official name includes "Mythos," or "Fable" (e.g., Claude Fable 5.1 or Claude Fable 6), or that Anthropic officially describes as a "Mythos-class" model or similar, will qualify for this market's resolution. Anthropic's other model tiers, such as Opus, Sonnet, or Haiku, will not qualify.
The percentage displayed as "HLE Accuracy" for the model in its result card on the "AI Progress on Humanity's Last Exam" chart at https://agi.safe.ai/ will be used to resolve this market. This market will resolve solely based on the displayed HLE Accuracy, regardless of the model's Calibration Error, chart position, other configuration scores, or any underlying granular or unrounded data presented elsewhere.
If multiple qualifying models are added to the Humanity's Last Exam results on the same calendar date (ET), the model with the highest HLE Accuracy will be used for resolution. Models added to the results on the calendar date following the initial qualifying model's first appearance will not be considered. If a model is first added to the Humanity's Last Exam results but is subsequently removed and not re-added, such that it is not displayed on the site at 12:00 PM ET on the calendar date following its first appearance, its appearance will not qualify as added to the Humanity's Last Exam results.
A qualifying model must be newly added to the Humanity's Last Exam results at https://agi.safe.ai/. Whether the model was previously released, publicly accessible, in beta, or otherwise available before appearing on the site is irrelevant for this market.
The resolution source for this market is the official Humanity's Last Exam website found at https://agi.safe.ai/. If this resolution source is unavailable at 12:00 PM ET on the calendar date following the date on which the qualifying model first appears on the site, this market will resolve based on the first subsequent instance at which the model's HLE Accuracy becomes available on the site. If it remains unavailable through the end of the seventh day after the qualifying model first appears on the site or if no qualifying model is added by December 31, 2026, 11:59 PM ET, this market will resolve to "No".
Market Opened: Sep 1, 2026, 11:31 AM ET
Volume
$21,881End Date
Dec 31, 2026Market Opened
Sep 1, 2026, 11:31 AM ETResolution Source
https://agi.safe.ai/Resolver
0x65070BE91...This market will resolve to "Yes" if the next Anthropic Mythos-class model added to the Humanity's Last Exam results at https://agi.safe.ai/ has an HLE Accuracy of at least the specified percentage at 12:00 PM ET on the calendar date following the date on which it first appears on the site. Otherwise, this market will resolve to "No".
Any model whose official name includes "Mythos," or "Fable" (e.g., Claude Fable 5.1 or Claude Fable 6), or that Anthropic officially describes as a "Mythos-class" model or similar, will qualify for this market's resolution. Anthropic's other model tiers, such as Opus, Sonnet, or Haiku, will not qualify.
The percentage displayed as "HLE Accuracy" for the model in its result card on the "AI Progress on Humanity's Last Exam" chart at https://agi.safe.ai/ will be used to resolve this market. This market will resolve solely based on the displayed HLE Accuracy, regardless of the model's Calibration Error, chart position, other configuration scores, or any underlying granular or unrounded data presented elsewhere.
If multiple qualifying models are added to the Humanity's Last Exam results on the same calendar date (ET), the model with the highest HLE Accuracy will be used for resolution. Models added to the results on the calendar date following the initial qualifying model's first appearance will not be considered. If a model is first added to the Humanity's Last Exam results but is subsequently removed and not re-added, such that it is not displayed on the site at 12:00 PM ET on the calendar date following its first appearance, its appearance will not qualify as added to the Humanity's Last Exam results.
A qualifying model must be newly added to the Humanity's Last Exam results at https://agi.safe.ai/. Whether the model was previously released, publicly accessible, in beta, or otherwise available before appearing on the site is irrelevant for this market.
The resolution source for this market is the official Humanity's Last Exam website found at https://agi.safe.ai/. If this resolution source is unavailable at 12:00 PM ET on the calendar date following the date on which the qualifying model first appears on the site, this market will resolve based on the first subsequent instance at which the model's HLE Accuracy becomes available on the site. If it remains unavailable through the end of the seventh day after the qualifying model first appears on the site or if no qualifying model is added by December 31, 2026, 11:59 PM ET, this market will resolve to "No".Anthropic’s September 1, 2026 release of Claude Mythos 5.1 and the closely related Fable 5.1 established new HLE leaderboard highs of 59.1–65 percent through targeted gains in cybersecurity, biology, and tool-augmented reasoning. These results, verified on the official CAIS/Scale AI board, outpace OpenAI’s GPT-6 Astra at 54.7 percent and other frontier entries clustered in the mid-40s, reinforcing trader expectations that the next Mythos-class model will clear 50–55 percent thresholds on debut. The benchmark’s 2,500 expert-authored questions across mathematics, physics, and multimodal tasks continue to resist saturation, keeping outcomes sensitive to any new Anthropic launch before year-end amid competitive pressure from Google DeepMind and Meta.
This market will resolve to "Yes" if the next Anthropic Mythos-class model added to the Humanity's Last Exam results at https://agi.safe.ai/ has an HLE Accuracy of at least the specified percentage at 12:00 PM ET on the calendar date following the date on which it first appears on the site. Otherwise, this market will resolve to "No".
Any model whose official name includes "Mythos," or "Fable" (e.g., Claude Fable 5.1 or Claude Fable 6), or that Anthropic officially describes as a "Mythos-class" model or similar, will qualify for this market's resolution. Anthropic's other model tiers, such as Opus, Sonnet, or Haiku, will not qualify.
The percentage displayed as "HLE Accuracy" for the model in its result card on the "AI Progress on Humanity's Last Exam" chart at https://agi.safe.ai/ will be used to resolve this market. This market will resolve solely based on the displayed HLE Accuracy, regardless of the model's Calibration Error, chart position, other configuration scores, or any underlying granular or unrounded data presented elsewhere.
If multiple qualifying models are added to the Humanity's Last Exam results on the same calendar date (ET), the model with the highest HLE Accuracy will be used for resolution. Models added to the results on the calendar date following the initial qualifying model's first appearance will not be considered. If a model is first added to the Humanity's Last Exam results but is subsequently removed and not re-added, such that it is not displayed on the site at 12:00 PM ET on the calendar date following its first appearance, its appearance will not qualify as added to the Humanity's Last Exam results.
A qualifying model must be newly added to the Humanity's Last Exam results at https://agi.safe.ai/. Whether the model was previously released, publicly accessible, in beta, or otherwise available before appearing on the site is irrelevant for this market.
The resolution source for this market is the official Humanity's Last Exam website found at https://agi.safe.ai/. If this resolution source is unavailable at 12:00 PM ET on the calendar date following the date on which the qualifying model first appears on the site, this market will resolve based on the first subsequent instance at which the model's HLE Accuracy becomes available on the site. If it remains unavailable through the end of the seventh day after the qualifying model first appears on the site or if no qualifying model is added by December 31, 2026, 11:59 PM ET, this market will resolve to "No".
Any model whose official name includes "Mythos," or "Fable" (e.g., Claude Fable 5.1 or Claude Fable 6), or that Anthropic officially describes as a "Mythos-class" model or similar, will qualify for this market's resolution. Anthropic's other model tiers, such as Opus, Sonnet, or Haiku, will not qualify.
The percentage displayed as "HLE Accuracy" for the model in its result card on the "AI Progress on Humanity's Last Exam" chart at https://agi.safe.ai/ will be used to resolve this market. This market will resolve solely based on the displayed HLE Accuracy, regardless of the model's Calibration Error, chart position, other configuration scores, or any underlying granular or unrounded data presented elsewhere.
If multiple qualifying models are added to the Humanity's Last Exam results on the same calendar date (ET), the model with the highest HLE Accuracy will be used for resolution. Models added to the results on the calendar date following the initial qualifying model's first appearance will not be considered. If a model is first added to the Humanity's Last Exam results but is subsequently removed and not re-added, such that it is not displayed on the site at 12:00 PM ET on the calendar date following its first appearance, its appearance will not qualify as added to the Humanity's Last Exam results.
A qualifying model must be newly added to the Humanity's Last Exam results at https://agi.safe.ai/. Whether the model was previously released, publicly accessible, in beta, or otherwise available before appearing on the site is irrelevant for this market.
The resolution source for this market is the official Humanity's Last Exam website found at https://agi.safe.ai/. If this resolution source is unavailable at 12:00 PM ET on the calendar date following the date on which the qualifying model first appears on the site, this market will resolve based on the first subsequent instance at which the model's HLE Accuracy becomes available on the site. If it remains unavailable through the end of the seventh day after the qualifying model first appears on the site or if no qualifying model is added by December 31, 2026, 11:59 PM ET, this market will resolve to "No".
Volume
$21,881End Date
Dec 31, 2026Market Opened
Sep 1, 2026, 11:31 AM ETResolution Source
https://agi.safe.ai/Resolver
0x65070BE91...Anthropic’s September 1, 2026 release of Claude Mythos 5.1 and the closely related Fable 5.1 established new HLE leaderboard highs of 59.1–65 percent through targeted gains in cybersecurity, biology, and tool-augmented reasoning. These results, verified on the official CAIS/Scale AI board, outpace OpenAI’s GPT-6 Astra at 54.7 percent and other frontier entries clustered in the mid-40s, reinforcing trader expectations that the next Mythos-class model will clear 50–55 percent thresholds on debut. The benchmark’s 2,500 expert-authored questions across mathematics, physics, and multimodal tasks continue to resist saturation, keeping outcomes sensitive to any new Anthropic launch before year-end amid competitive pressure from Google DeepMind and Meta.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · Updated
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