Anthropic’s Mythos-class models, including the newly introduced Claude Mythos 5.1 and Fable 5.1 variants launched September 1, 2026, represent the lab’s frontier tier optimized for cybersecurity and biology research with reduced safeguards. These models have driven recent gains on Humanity’s Last Exam (HLE), a 2,500-question expert-level benchmark spanning mathematics, physics, and humanities that remains far from saturation. As of the September 1 leaderboard update, Fable 5.1 leads at 65% accuracy while Mythos 5 sits at 64.5%, ahead of GPT-5.4 Pro (58.7%) and Meta’s Muse Spark 1.1 (62.1%). Trader sentiment reflects Anthropic’s consistent edge in verified HLE results since the benchmark’s 2025 launch, alongside expectations for incremental updates before year-end, though clustering near 65% signals potential diminishing returns on further gains without major architectural shifts.
Experimental AI-generated summary referencing Polymarket data. This is not trading advice and plays no role in how this market resolves. · UpdatedNEW
Dec 31, 2026
45%+
94%
50%+
90%
55%+
53%
60%+
10%
$5,906 Vol.
45%+
$564 Vol.
94%
50%+
$1,026 Vol.
90%
55%+
$1,494 Vol.
53%
60%+
$2,855 Vol.
10%
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 Mythos-class models, including the newly introduced Claude Mythos 5.1 and Fable 5.1 variants launched September 1, 2026, represent the lab’s frontier tier optimized for cybersecurity and biology research with reduced safeguards. These models have driven recent gains on Humanity’s Last Exam (HLE), a 2,500-question expert-level benchmark spanning mathematics, physics, and humanities that remains far from saturation. As of the September 1 leaderboard update, Fable 5.1 leads at 65% accuracy while Mythos 5 sits at 64.5%, ahead of GPT-5.4 Pro (58.7%) and Meta’s Muse Spark 1.1 (62.1%). Trader sentiment reflects Anthropic’s consistent edge in verified HLE results since the benchmark’s 2025 launch, alongside expectations for incremental updates before year-end, though clustering near 65% signals potential diminishing returns on further gains without major architectural shifts.
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
$5,906End 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 Mythos-class models, including the newly introduced Claude Mythos 5.1 and Fable 5.1 variants launched September 1, 2026, represent the lab’s frontier tier optimized for cybersecurity and biology research with reduced safeguards. These models have driven recent gains on Humanity’s Last Exam (HLE), a 2,500-question expert-level benchmark spanning mathematics, physics, and humanities that remains far from saturation. As of the September 1 leaderboard update, Fable 5.1 leads at 65% accuracy while Mythos 5 sits at 64.5%, ahead of GPT-5.4 Pro (58.7%) and Meta’s Muse Spark 1.1 (62.1%). Trader sentiment reflects Anthropic’s consistent edge in verified HLE results since the benchmark’s 2025 launch, alongside expectations for incremental updates before year-end, though clustering near 65% signals potential diminishing returns on further gains without major architectural shifts.
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
$5,906End Date
Dec 31, 2026Market Opened
Sep 1, 2026, 11:31 AM ETResolution Source
https://agi.safe.ai/Resolver
0x65070BE91...Anthropic’s Mythos-class models, including the newly introduced Claude Mythos 5.1 and Fable 5.1 variants launched September 1, 2026, represent the lab’s frontier tier optimized for cybersecurity and biology research with reduced safeguards. These models have driven recent gains on Humanity’s Last Exam (HLE), a 2,500-question expert-level benchmark spanning mathematics, physics, and humanities that remains far from saturation. As of the September 1 leaderboard update, Fable 5.1 leads at 65% accuracy while Mythos 5 sits at 64.5%, ahead of GPT-5.4 Pro (58.7%) and Meta’s Muse Spark 1.1 (62.1%). Trader sentiment reflects Anthropic’s consistent edge in verified HLE results since the benchmark’s 2025 launch, alongside expectations for incremental updates before year-end, though clustering near 65% signals potential diminishing returns on further gains without major architectural shifts.
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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