Fable 5

Type: AI model

Fable 5 is the shorthand for Anthropic’s Claude Fable 5, the publicly available, safety-gated flagship of the fifth Claude generation released June 2026. It tops most benchmarks among generally available models, including roughly 80% on SWE-Bench Pro. GROUNDING tracks Fable 5’s benchmarks, guardrails, and relationship to the partner-only Mythos 5.

Recent Updates

• 2026-07-07: DAIR.AI retweets an opinion on agent orchestration across multiple models (DAIR.AI) · twitter.com — Agents DAIR.AI · Opus 4.8 · GPT 5.5 · GLM-5.2
• 2026-07-08: RuBench benchmarks repository-level coding agents on Russian task specs (cs.CL updates on arXiv.org) · arxiv.org — Code Agents LLM Evals Opus 4.8 · Sonnet 5 · Haiku 4.5 · GPT 5.5
• 2026-07-09: Judge–executor split: Fable 5 evaluator with GPT-5.5 executor (DAIR.AI) · twitter.com — LLM Evals Agents GPT 5.5 · GPT-5.6
• 2026-07-10: OpenAI launches GPT-5.6 family and expands Codex/ChatGPT stack (Latent.Space) · latent.space — Agents Tool Use Code Agents LLM Evals OpenAI · Meta Superintelligence Labs · Latent.Space Sam Altman Greg Brockman · GPT-5.6 Sol · GPT-5.6 Terra · GPT-5.6 Luna · Muse Spark 1.1 · Opus 4.8
• 2026-07-10: OpenAI launches GPT-5.6 and ChatGPT Work, with multi-agent execution and programmatic tool calling (量子位) · qbitai.com — Agents Tool Use Code Agents OpenAI · Anthropic · Google · Microsoft · Slack · Notion · SharePoint Microsoft Teams · Gmail · Oracle · QbitAI Autonomous Sam Altman Matt Shumer nasqret 听雨 · GPT-5.6 · GPT-5.6 Sol · GPT-5.6 Terra · GPT-5.6 Luna · GPT 5.5 · Claude Opus 4.8
• 2026-07-10: A wave of flagship model launches lands across Anthropic, OpenAI, xAI, and Meta (Все статьи подряд / Искусственный интеллект / Хабр) · habr.com — LLM Evals Code Agents Anthropic · OpenAI · SpaceXAI · Meta · xAI Mark Zuckerberg Musk · Mythos 5 · GPT-5.6 · Sol · Terra · Luna · GPT-Live · Grok 4.5 · Muse Spark 1.1 · Opus 4.8 · Opus 4.7 · GPT 5.5
• 2026-07-12: Anthropic extends Fable 5 access on paid plans through July 19 (Simon Willison’s Weblog) · simonwillison.net — Anthropic · OpenAI Simon Willison · GPT-5.6 Sol
• 2026-07-13: Weekly AI digest highlights model releases, MCP tooling, and a major Google fine (‌эйай ньюз) · x.ai — Long Context MCP Code Agents Meituan · Huawei · Anthropic · Amazon · Meta · SpaceXAI · Cursor · OpenAI · Google · EU · Comfy · ChatGPT · Codex · LongCat 2.0 · Claude Sonnet 5 · Opus 4.8 · Muse Spark 1.1 · Grok 4.5 · GPT-5.6 · Terra · Luna · Muse Image · Muse Video
• 2026-07-13: alphaXiv says GPT-5.6 was more focused in an autoresearch reproduction task (alphaXiv) · twitter.com — Agents LLM Evals OpenAI · alphaXiv · GPT-5.6 · GPT-5.6 Sol · GPT 5.5
• 2026-07-14: DOOMQL: a Doom-like game driven by SQL in SQLite (Simon Willison’s Weblog) · simonwillison.net — OpenAI · Anthropic · GitHub Simon Willison Peter Gostev · GPT-5.6 Sol
• 2026-07-16: Mermaid diagrams to Unicode box art: Porting Grok CLI’s renderer to the web (Simon Willison’s Weblog) · simonwillison.net — xAI · Anthropic Simon Willison
• 2026-07-16: Schema Harness Claims ~99% on ARC-AGI-3 Public (Hacker News) · schema-harness.github.io — LLM Evals Agents Context Engineering Impossible Research University of California, Berkeley · Carnegie Mellon University · GPT-5.6 Sol · Opus 4.8
• 2026-07-17: Kimi K3 posts benchmark gains and Moonshot AI signals open-weight release (Kimi.ai) · x.com — LLM Evals Agents Tool Use Kimi.ai · Artificial Analysis · Moonshot AI · Zapier · Kimi K3 · Opus 4.8 · GPT 5.5 · GPT-5.6 Sol · K2.6 · GLM-5.2 · Claude Opus 4.8 · Claude Fable 5
• 2026-07-17: Kimi K3 reportedly scores 57 on Artificial Analysis Intelligence Index (Kimi.ai) · x.com — LLM Evals Open Source LLMs Kimi.ai · Artificial Analysis · Moonshot AI · Kimi K3 · Opus 4.8 · GPT 5.5 · GPT-5.6 Sol
• 2026-07-18: Anthropic keeps Fable 5 in subscription plans (@ai_newz) · t.me — Anthropic
• 2026-07-18: Fable 5 vs. GPT-5.6 Sol on an NP-hard optimization benchmark (Hacker News) · charlesazam.com — Code Agents Tool Use LLM Evals Anthropic CLIArena · GPT-5.6 Sol · Haiku
• 2026-07-19: Weekly AI digest highlights model releases, open-source audio, and a new OpenAI merch device (@ai_newz) · t.me — Open Source LLMs Agents Anthropic · Moonshot · OpenAI · GigaChat Suno Kyutai · Epic Games YouTube Music · Kimi K3 · Qwen3.6 GigaAM Multilingual MIRA · Opus 4.8
• 2026-07-20: Kimi K3 launch drives subscription pause and rapid business growth claims (量子位) · qbitai.com — Code Agents LLM Evals 月之暗面 量子位 · QbitAI · Bloomberg 梦瑶 · Kimi K3 · GPT-5.6 Sol DeepSWE Program Bench SWE Marathon · Opus 4.8
• 2026-07-21: Claude Code team on dogfooding, prompt compression, and automated code review (Simon Willison’s Weblog) · simonwillison.net — Code Agents Context Engineering Anthropic · YouTube Cat Wu Thariq Shihipar Simon Willison · Opus 4.8 Opus 4 Sonnet 3.7
• 2026-07-21: Perplexity as a signal of model similarity and ensemble diversity (@turboproject) · t.me — LLM Evals DeepSeek · LM Arena · Kimi K3 · DeepSeek V4 · Claude
• 2026-07-21: Kimi K3 benchmark report compares it with Fable 5 on agentic tasks (Hacker News) · fireworks.ai — Agents Tool Use LLM Evals Code Agents Kimi K3
• 2026-07-22: ActiveVision benchmark tests repeated visual observation and reasoning (alphaXiv) · x.com — LLM Evals alphaXiv · X JiaruiZ58876329
• 2026-07-24: Claude Cookbook roundup covers agent workflows, eval loops, memory, and managed agents (Hacker News) · platform.claude.com — Agents Tool Use MCP Context Engineering Code Agents LLM Evals Agent Memory Anthropic · OpenAI · Modal · Docker · Opus 4.8
• 2026-07-24: Tech companies urge U.S. policymakers not to restrict open-weight models (Hacker News) · cnbc.com — Open Source LLMs NVIDIA · Microsoft · Meta · Palantir · OpenAI · Anthropic · Moonshot AI · Hugging Face · z.ai · SpaceX · CNBC · White House U.S. Treasury · SEC Jensen Huang Satya Nadella Elon Musk Greg Brockman Sam Altman Yacine Jernite Michael Kratsios Scott Bessent · Kimi K3 · GLM-5.2
• 2026-07-25: Anthropic’s Opus 5 is reported to match or beat Fable 5 on several benchmarks while Claude Code’s system prompt was cut by more than 80% (量子位) · qbitai.com — Code Agents Context Engineering LLM Evals Anthropic · QbitAI · Cursor · OpenAI AlphaSchool 克雷西 am.will OmedTheVibeCoder Alex Ermolov Chetaslua Noema Matt Shumer Victor M Thariq · Opus 5 · Opus 4.8 · GPT-5.6 Sol · GPT-5.6 · Kimi K3

Incident radar

GROUNDING’s Hallucination Incident Index has flagged 3 incidents naming Fable 5 — a heuristic proxy over the AI-news radar’s daily journal (hallucination/jailbreak/refusal/bias keyword matches), not a verified incident registry.

• Severity: S3 1 · S4 2
• Category: Hallucination 1 · Bias 2

Most recent:

• Using a separate judge model to enforce /goal workflows source (2026-07-17)
• Using LLMs to Automate MikroTik Network Configuration source (2026-07-15)
• OpenRouter Fusion benchmark analysis against Claude Fable source (2026-07-14)

Full breakdown: Hallucination Incident Index · Subscribe: incident-index RSS feed

FAQ

What is Fable 5?

Fable 5 is the shorthand for Anthropic’s Claude Fable 5, the publicly available, safety-gated flagship of the fifth Claude generation released June 2026. It tops most benchmarks among generally available models, including roughly 80% on SWE-Bench Pro. GROUNDING tracks Fable 5’s benchmarks, guardrails, and relationship to the partner-only Mythos 5.

What does this page track?

Dated radar mentions, source links, related concepts, and builder-relevant context for Fable 5, collected automatically by GROUNDING.

When was Fable 5 last mentioned?

Fable 5 was most recently mentioned in a radar update dated 2026-07-25.

Category: Text / Language Models