
Micah Hill-Smith
172 posts

Micah Hill-Smith
@_micah_h
Co-founder & CEO @ArtificialAnlys. Previously @McKinsey.





Announcing AA-Briefcase, the benchmark for the next era of agentic knowledge work AA-Briefcase is our new benchmark for testing models on long-horizon knowledge work tasks in complex projects built by industry experts. Models are evaluated on multi-week projects, each with many linked tasks and thousands of input source files. We evaluated Claude Fable 5 from @AnthropicAI before it became unavailable, and it currently leads with an Elo score of 1587, followed by Claude Opus 4.8 (max, 1356), Opus 4.7, and the recently-released GLM 5.2 (max, 1266) from @Zai_org. Claude Fable 5 cost $31 on average to run each AA-Briefcase task, followed by Claude Opus 4.8 at $10.40, GPT-5.5 (xhigh) at $3.68 and GLM-5.2 (max) at $2.40. AA-Briefcase comprises four private scenarios, each representing a multi-week knowledge work project set in a realistic organizational context. A public fifth scenario has been released via @huggingface as a representation of scenario structure, submission, and grading (AA-Briefcase Lite). This does not count toward official AA-Briefcase results, and is demonstrative only. Key elements of AA-Briefcase: ➤ Realistic long-horizon projects: AA-Briefcase moves beyond single, disconnected prompts by evaluating models across a coherent long-horizon project. Tasks build week by week, draw on shared institutional context, and require deliverables such as financial models, board presentations, and design mock-ups ➤ Large volumes of fragmented context: AA-Briefcase requires models to reason across thousands of inputs, including company documents, meeting transcripts, large-scale data exports, 25,000+ Slack messages and 3,500+ emails. These sources are fragmented, messy, and often contain realistic contradiction, testing whether models can navigate the ambiguity of real-world knowledge work ➤ Composite rubric and pairwise grading: AA-Briefcase combines binary rubric checks for ground-truth correctness with pairwise grading on analytical quality and presentation quality. Unlike many evaluations that focus on a single metric, AA-Briefcase tests agentic capabilities more comprehensively, exposing cases where models produce outputs that look polished but are incorrect or lack analytical rigor ➤ Built by industry experts: AA-Briefcase scenarios mirror real-world knowledge work, with tasks developed over months by experts across data science, product management and corporate strategy from companies including Google, McKinsey & Company and BCG. Task challenges are drawn from professional experience, making AA-Briefcase more reflective of the ambiguity, messy context and competing priorities that define real-world knowledge work Key results: ➤ Claude Fable 5 leads AA-Briefcase at 1587 Elo: This is followed by Claude Opus 4.8 (1356) with the next-best non-Anthropic model, GLM-5.2 (max), ~90 points back at 1266. Note that Claude Fable 5 did not use the Opus 4.8 fallback for any task in AA-Briefcase ➤ Cost per task varies by ~800x across models tested: Claude Fable 5 leads the benchmark but costs more than $31 per task on average, compared to ~$0.04 for DeepSeek V4 Flash (max). The strongest price/performance options are open weights models such as GLM-5.2 (max) and DeepSeek V4 Pro (max), with GLM-5.2 (max) scoring only ~90 Elo below Claude Opus 4.8 (max) for less than 25% of the cost ➤ Real-world complexity remains difficult for models: The top performer, Claude Fable 5, satisfies all rubric criteria on just 3% of AA-Briefcase tasks. On 31 of 91 tasks, no model scores above 50% on the rubric criteria ➤ Task difficulty scales with the number of required input files: For each rubric check, we identify the set of source files needed to pass. Across all models, pass rates fall as this file count increases, though top-tier models degrade less than weaker models More details below in thread ⬇️

Announcing AA-Briefcase, the benchmark for the next era of agentic knowledge work AA-Briefcase is our new benchmark for testing models on long-horizon knowledge work tasks in complex projects built by industry experts. Models are evaluated on multi-week projects, each with many linked tasks and thousands of input source files. We evaluated Claude Fable 5 from @AnthropicAI before it became unavailable, and it currently leads with an Elo score of 1587, followed by Claude Opus 4.8 (max, 1356), Opus 4.7, and the recently-released GLM 5.2 (max, 1266) from @Zai_org. Claude Fable 5 cost $31 on average to run each AA-Briefcase task, followed by Claude Opus 4.8 at $10.40, GPT-5.5 (xhigh) at $3.68 and GLM-5.2 (max) at $2.40. AA-Briefcase comprises four private scenarios, each representing a multi-week knowledge work project set in a realistic organizational context. A public fifth scenario has been released via @huggingface as a representation of scenario structure, submission, and grading (AA-Briefcase Lite). This does not count toward official AA-Briefcase results, and is demonstrative only. Key elements of AA-Briefcase: ➤ Realistic long-horizon projects: AA-Briefcase moves beyond single, disconnected prompts by evaluating models across a coherent long-horizon project. Tasks build week by week, draw on shared institutional context, and require deliverables such as financial models, board presentations, and design mock-ups ➤ Large volumes of fragmented context: AA-Briefcase requires models to reason across thousands of inputs, including company documents, meeting transcripts, large-scale data exports, 25,000+ Slack messages and 3,500+ emails. These sources are fragmented, messy, and often contain realistic contradiction, testing whether models can navigate the ambiguity of real-world knowledge work ➤ Composite rubric and pairwise grading: AA-Briefcase combines binary rubric checks for ground-truth correctness with pairwise grading on analytical quality and presentation quality. Unlike many evaluations that focus on a single metric, AA-Briefcase tests agentic capabilities more comprehensively, exposing cases where models produce outputs that look polished but are incorrect or lack analytical rigor ➤ Built by industry experts: AA-Briefcase scenarios mirror real-world knowledge work, with tasks developed over months by experts across data science, product management and corporate strategy from companies including Google, McKinsey & Company and BCG. Task challenges are drawn from professional experience, making AA-Briefcase more reflective of the ambiguity, messy context and competing priorities that define real-world knowledge work Key results: ➤ Claude Fable 5 leads AA-Briefcase at 1587 Elo: This is followed by Claude Opus 4.8 (1356) with the next-best non-Anthropic model, GLM-5.2 (max), ~90 points back at 1266. Note that Claude Fable 5 did not use the Opus 4.8 fallback for any task in AA-Briefcase ➤ Cost per task varies by ~800x across models tested: Claude Fable 5 leads the benchmark but costs more than $31 per task on average, compared to ~$0.04 for DeepSeek V4 Flash (max). The strongest price/performance options are open weights models such as GLM-5.2 (max) and DeepSeek V4 Pro (max), with GLM-5.2 (max) scoring only ~90 Elo below Claude Opus 4.8 (max) for less than 25% of the cost ➤ Real-world complexity remains difficult for models: The top performer, Claude Fable 5, satisfies all rubric criteria on just 3% of AA-Briefcase tasks. On 31 of 91 tasks, no model scores above 50% on the rubric criteria ➤ Task difficulty scales with the number of required input files: For each rubric check, we identify the set of source files needed to pass. Across all models, pass rates fall as this file count increases, though top-tier models degrade less than weaker models More details below in thread ⬇️





GDPval-AA v2 is the highest weighted evaluation in the Intelligence Index v4.1. The upgrade re-baselines ELO to human performance at 1000, introduces a rotating panel of frontier-model judges, and raises the turn limit from 100 to 250 for longer-horizon agent trajectories. Claude Fable 5 (with fallback) leads at 1818, followed by Claude Opus 4.8 (1638). GPT-5.5 (xhigh) scores 1531. Claude Fable 5 is not currently available for use







Claude Fable 5 launched today at #1 on the Artificial Analysis Intelligence Index, putting Anthropic nearly 5 points ahead of any other lab’s best model We supported @AnthropicAI with pre-release evaluation of Claude Fable 5. Claude Fable 5 scores 64.9 on the Artificial Analysis Intelligence Index, claiming the #1 rank overall. It is ~5 points ahead of the closest non-Anthropic model (GPT-5.5), and Anthropic models now occupy both of the top 2 places. Key takeaways for Claude Fable 5 (adaptive reasoning with max effort and Opus 4.8 as fallback model): ➤ New safety guardrails for Mythos-class models: Claude Fable 5 uses the same underlying model as Claude Mythos 5 for public usage, with additional guardrails for potentially-harmful cybersecurity, biology, chemistry, and distillation-related queries. We tested Fable 5 using Anthropic’s new ‘fallback’ mechanism, which can route safety-flagged messages to Claude Opus 4.8. Anthropic states that fallback occurs in fewer than 5% of sessions on average, and we recorded fallback routing in ~8% of tasks across the Intelligence Index (mostly in scientific questions from evaluations like GPQA, AA-Omniscience and Humanity’s Last Exam) ➤ State-of-the-art Intelligence: Claude Fable 5 takes the #1 position on the Artificial Analysis Intelligence Index, scoring 64.9 and setting the highest score on 5 of the 10 underlying benchmarks. On AA-Omniscience, our knowledge and hallucination benchmark, Fable 5 scores 40, +7 points over the previous leader, Gemini 3.1 Pro Preview, driven primarily by higher accuracy. We generally observe a strong relationship between AA-Omniscience accuracy and model size in open weights models, which suggests Fable 5 could be larger than previous public Anthropic models ➤ Frontier agentic capability: Claude Fable 5 is at the frontier across all three agentic evaluations in the Index: GDPval-AA (real-world work tasks), Terminal-Bench Hard (agentic coding), and Tau2-bench Telecom (tool use for customer service). Its GDPval-AA Elo of 1932 is a significant jump from the previous leader, Claude Opus 4.8, further extending Anthropic’s lead in agentic capabilities ➤ Leading HLE score, but refusal and fallback in 9% of tasks: Claude Fable 5 scores 53% on Humanity’s Last Exam, more than 7 points ahead of the next-best model, Claude Opus 4.8 (max). Fable 5 triggers safety guardrails on 9% of HLE tasks, falling back to Claude Opus 4.8. Including this fallback usage, running HLE with Fable 5 costs ~$2.2k, the highest of any model we have evaluated Key model details: ➤ Context window: Claude Fable 5 retains the same 1M token context window as Claude Opus 4.8 ➤ Price: Claude Fable 5 is priced at $10/$50 per 1M input/output tokens, 2x the token price of Claude Opus 4.8. The cache write/read price is $12.50/$1 per million tokens ➤ Availability: Claude Fable 5 is included in Pro, Max, Team, and seat-based Enterprise plans through June 22, consuming 2x Opus usage. From June 23, usage will require credits, with Anthropic saying it plans to restore subscription access once capacity allows










xAI’s new Grok Voice Agent is the new leading Speech to Speech model, surpassing Gemini 2.5 Flash Native Audio and GPT Realtime in our Big Bench Audio benchmark The new model achieves a score of 92.3% on Big Bench Audio, just ahead of the previous leader, Google’s Gemini 2.5 Flash Native Audio Thinking. This model is @xAI’s first public Speech to Speech API, bringing increased competition to the space. The model has tool calling support and xAI has said it’s ready to be used across voice assistants, phone agents, and interactive voice applications. Benchmark context: Big Bench Audio is the first dedicated dataset for evaluating reasoning performance of speech models. Big Bench Audio comprises 1,000 audio questions adapted from the Big Bench Hard text test set, chosen for its rigorous testing of advanced reasoning, translated into the audio domain. Performance: ➤ Reasoning: Achieves 92.3% on Big Bench Audio, setting a new state-of-the-art for native Speech to Speech reasoning. Congratulations @xai and @elonmusk on this impressive release! ➤ Latency: At an average time to first token of 0.78 seconds, it is the third fastest model on our leaderboard behind Google’s Gemini 2.5 Flash Native Audio Dialog and Gemini 2.5 Flash Live ➤ Price: Simple pricing of 5 cents per minute connected, or $3 per hour of audio Key features: ➤ Tool calling: Use built-in tools such as web search, RAG-powered search, or define your own tools with JSON schema ➤ Telephony: Connect to Session Initiation Protocol (SIP) providers like Twilio and Vonage ➤ Multilingual: Converse in over 100 languages with 5 voices to choose from


Announcing AA-Omniscience, our new benchmark for knowledge and hallucination across >40 topics, where all but three models are more likely to hallucinate than give a correct answer Embedded knowledge in language models is important for many real world use cases. Without knowledge, models make incorrect assumptions and are limited in their ability to operate in real world contexts. Tools like web search can support but models need to know what to search for (e.g. models should not search for ‘Multi Client Persistence’ for an MCP query when it clearly refers to ‘Model Context Protocol’). Hallucination of factual information is a barrier to being able to rely on models and has been perpetuated by every major evaluation dataset. Grading correct answers with no penalty for incorrect answers creates an incentive for models (and the labs training them) to attempt every question. This problem is clearest when it comes to knowledge: factual information should never be made up, while in other contexts attempts that might not work are useful (e.g. coding new features). Omniscience Index is the the key metric we report for AA-Omniscience, and it punishes hallucinations by deducting points where models have guessed over admitting they do not know the answer. AA-Omniscience shows that all but three models are more likely to hallucinate than provide a correct answer when given a difficult question. AA-Omniscience will complement the Artificial Analysis Intelligence Index to incorporate measurement of knowledge and probability of hallucination. Details below, and more charts in the thread. AA-Omniscience details: - 🔢6,000 questions across 42 topics within 6 domains (’Business’, ‘Humanities & Social Sciences’, ‘Health’, ‘Law’, ‘Software Engineering’, and ‘Science, Engineering & Mathematics’) - 🔍 89 sub-topics including Python data libraries, Public Policy, Taxation, and more, giving a sharper view of where models excel and where they fall short across nuanced domains - 🔄 Incorrect answers are penalized in our Knowledge Reliability Index metrics to punish hallucinations - 📊3 Metrics: Accuracy (% correct), Hallucination rate (% incorrect of incorrect/abstentions), Omniscience Index (+1 for correct, -1 for incorrect where answered, 0 for abstentions where the model did not try to answer) - 🤗 Open source test dataset: We’re open sourcing 600 questions (10%) to support labs develop factual and reliable models. Topic distribution and model performance follows the full set (@huggingface link below) - 📃 Paper: See below for a link to the research paper Key findings: - 🥇 Claude 4.1 Opus takes first place in Omniscience Index, followed by last week’s GPT-5.1 and Grok 4: Even the best frontier models score only slightly above 0, meaning they produce correct answers on the difficult questions that make up AA-Omniscience only marginally more often than incorrect ones. @AnthropicAI’s leadership is driven by low hallucination rate, whereas OpenAI and xAI’s positions are primarily driven by higher accuracy (percentage correct). - 🥇 xAI’s Grok 4 takes first place in Omniscience Accuracy (our simple ‘percentage correct’ metric), followed by GPT-5 and Gemini 2.5 Pro: @xai's win may be enabled by scaling total parameters and pre-training compute: @elonmusk revealed last week that Grok 4 has 3 trillion total parameters, which may be larger than GPT-5 and other proprietary models - 🥇 Claude sweeps the hallucination leaderboard: Anthropic takes the top three spots for lowest hallucination rate, with Claude 4.5 Haiku leading at 28%, over three times lower than GPT-5 (high) and Gemini 2.5 Pro. Claude 4.5 Sonnet and Claude 4.1 Opus follow in second and third at 48% - 💭 High knowledge does not guarantee low hallucination: Hallucination rate measures how often a model guesses when it lacks the required knowledge. Models with the highest accuracy, including the GPT-5 models and Gemini 2.5 Pro, do not lead the Omniscience Index due to their tendency to guess over abstaining. Anthropic models tend to manage uncertainty better, with Claude 4.5 Haiku achieving the lowest hallucination rate at 26%, ahead of 4.5 Sonnet and 4.1 Opus (48%) - 📊 Models vary by domain: Models differ in their performance across the six domains of AA-Omniscience - no model dominates across all. While Anthropic’s Claude 4.1 Opus leads in Law, Software Engineering, and Humanities & Social Sciences, GPT-5.1 from @OpenAI achieves the highest reliability on Business questions, and xAI’s Grok 4 performs best in Health and in Science, Engineering & Mathematics. Model choice should align with the the use case rather than choosing the overall leader - 📈 Larger models score higher on accuracy, but not always reliability: Larger models tend to have higher levels of embedded knowledge, with Kimi K2 Thinking and DeepSeek R1 (0528) topping accuracy charts over smaller models. This advantage does not always hold on the Omniscience Index. For example, Llama 3.1 405B from @AIatMeta beats larger Kimi K2 variants due to having one of the lowest hallucination rates among models (51%)


Announcing AA-Omniscience, our new benchmark for knowledge and hallucination across >40 topics, where all but three models are more likely to hallucinate than give a correct answer Embedded knowledge in language models is important for many real world use cases. Without knowledge, models make incorrect assumptions and are limited in their ability to operate in real world contexts. Tools like web search can support but models need to know what to search for (e.g. models should not search for ‘Multi Client Persistence’ for an MCP query when it clearly refers to ‘Model Context Protocol’). Hallucination of factual information is a barrier to being able to rely on models and has been perpetuated by every major evaluation dataset. Grading correct answers with no penalty for incorrect answers creates an incentive for models (and the labs training them) to attempt every question. This problem is clearest when it comes to knowledge: factual information should never be made up, while in other contexts attempts that might not work are useful (e.g. coding new features). Omniscience Index is the the key metric we report for AA-Omniscience, and it punishes hallucinations by deducting points where models have guessed over admitting they do not know the answer. AA-Omniscience shows that all but three models are more likely to hallucinate than provide a correct answer when given a difficult question. AA-Omniscience will complement the Artificial Analysis Intelligence Index to incorporate measurement of knowledge and probability of hallucination. Details below, and more charts in the thread. AA-Omniscience details: - 🔢6,000 questions across 42 topics within 6 domains (’Business’, ‘Humanities & Social Sciences’, ‘Health’, ‘Law’, ‘Software Engineering’, and ‘Science, Engineering & Mathematics’) - 🔍 89 sub-topics including Python data libraries, Public Policy, Taxation, and more, giving a sharper view of where models excel and where they fall short across nuanced domains - 🔄 Incorrect answers are penalized in our Knowledge Reliability Index metrics to punish hallucinations - 📊3 Metrics: Accuracy (% correct), Hallucination rate (% incorrect of incorrect/abstentions), Omniscience Index (+1 for correct, -1 for incorrect where answered, 0 for abstentions where the model did not try to answer) - 🤗 Open source test dataset: We’re open sourcing 600 questions (10%) to support labs develop factual and reliable models. Topic distribution and model performance follows the full set (@huggingface link below) - 📃 Paper: See below for a link to the research paper Key findings: - 🥇 Claude 4.1 Opus takes first place in Omniscience Index, followed by last week’s GPT-5.1 and Grok 4: Even the best frontier models score only slightly above 0, meaning they produce correct answers on the difficult questions that make up AA-Omniscience only marginally more often than incorrect ones. @AnthropicAI’s leadership is driven by low hallucination rate, whereas OpenAI and xAI’s positions are primarily driven by higher accuracy (percentage correct). - 🥇 xAI’s Grok 4 takes first place in Omniscience Accuracy (our simple ‘percentage correct’ metric), followed by GPT-5 and Gemini 2.5 Pro: @xai's win may be enabled by scaling total parameters and pre-training compute: @elonmusk revealed last week that Grok 4 has 3 trillion total parameters, which may be larger than GPT-5 and other proprietary models - 🥇 Claude sweeps the hallucination leaderboard: Anthropic takes the top three spots for lowest hallucination rate, with Claude 4.5 Haiku leading at 28%, over three times lower than GPT-5 (high) and Gemini 2.5 Pro. Claude 4.5 Sonnet and Claude 4.1 Opus follow in second and third at 48% - 💭 High knowledge does not guarantee low hallucination: Hallucination rate measures how often a model guesses when it lacks the required knowledge. Models with the highest accuracy, including the GPT-5 models and Gemini 2.5 Pro, do not lead the Omniscience Index due to their tendency to guess over abstaining. Anthropic models tend to manage uncertainty better, with Claude 4.5 Haiku achieving the lowest hallucination rate at 26%, ahead of 4.5 Sonnet and 4.1 Opus (48%) - 📊 Models vary by domain: Models differ in their performance across the six domains of AA-Omniscience - no model dominates across all. While Anthropic’s Claude 4.1 Opus leads in Law, Software Engineering, and Humanities & Social Sciences, GPT-5.1 from @OpenAI achieves the highest reliability on Business questions, and xAI’s Grok 4 performs best in Health and in Science, Engineering & Mathematics. Model choice should align with the the use case rather than choosing the overall leader - 📈 Larger models score higher on accuracy, but not always reliability: Larger models tend to have higher levels of embedded knowledge, with Kimi K2 Thinking and DeepSeek R1 (0528) topping accuracy charts over smaller models. This advantage does not always hold on the Omniscience Index. For example, Llama 3.1 405B from @AIatMeta beats larger Kimi K2 variants due to having one of the lowest hallucination rates among models (51%)






xAI has released Grok 4 Fast - breaking through our intelligence vs cost frontier by achieving Gemini 2.5 Pro level intelligence at a ~25X cheaper cost Intelligence: @xai shared with us pre-release access to Grok 4 Fast. In reasoning mode, the model scores an impressive 60 on our Artificial Analysis Intelligence Index, in line with Gemini 2.5 Pro and Claude 4.1 Opus, while sitting as expected below the prior Grok 4 release and GPT-5 (high). Grok 4 Fast performed especially well on coding evaluations, taking the number one spot on our leaderboard for LiveCodeBench, even outperforming its larger sibling Grok 4. Cost: xAI is offering Grok 4 Fast at a very competitive price of only $0.2/1M Input Tokens and $0.5/1M output tokens. The model is also quite token efficient compared to other reasoning models, taking 61M tokens to complete our intelligence index, significantly less than Gemini 2.5 Pro’s 93M and Grok 4’s 120M. This competitive pricing and efficiency translates to the cost of running Artificial Analysis Intelligence Index being ~25X lower than Gemini 2.5 Pro and ~23X lower than GPT-5 (reasoning mode high). Speed: When benchmarking the pre-release API, xAI’s endpoint for the model was very fast, achieving 344 output tokens per second - ~2.5X faster than OpenAI’s GPT-5 API. This also allows for End to End Latency results that are faster than most non-reasoning models for many workloads. Speeds may drop as traffic on the API increases - keep an eye on our live performance benchmarking to see how this evolves. Congratulations to the @xai team and @elonmusk on this new release! See below for more details and in-depth analysis 👇
