Claude
Claude Fable 5 & Opus 4.8 — Anthropic
Anthropic's precision agent for complex tasks. Fable 5 is the first publicly available Mythos-class model — 80.3% on SWE-bench Pro, leading every flagship by double digits. Opus 4.8 ships Dynamic Workflows and effort control as the everyday workhorse. The 1M context still reads your entire codebase and remembers page 847.
Fable 5 Released
Jun 9, 2026
Context
1M tokens
Starting Price
$20/mo (Pro)
Max Output
128K tokens
01
Overview
Claude is Anthropic's flagship AI assistant, designed with a focus on being helpful, harmless, and honest. It's not the flashiest name in AI, but it's the model that developers and enterprises keep coming back to when the work actually matters.
June 2026 changed the lineup. Claude Fable 5 (released June 9) is the first publicly available "Mythos-class" model — a full tier above Opus and the most capable thing Anthropic has ever shipped broadly. Days before the release, Anthropic publicly warned that AI was getting too dangerous; then they shipped Mythos to the public anyway, citing new safeguards around cybersecurity and biology.
The benchmark gap is real: Fable 5 scores 80.3% on SWE-bench Pro vs. 69.2% for Opus 4.8, 58.6% for GPT-5.5, and 54.2% for Gemini 3.1 Pro. It supports adaptive thinking, effort, task budgets, memory, context editing, compaction, and vision at launch — 1M-token context and 128K output, no separate tiers.
Claude Opus 4.8 (released May 28) stays the everyday workhorse. Its headline addition is Dynamic Workflows: a research-preview feature where Claude plans the work, spawns hundreds of parallel subagents, and verifies its own outputs — built for codebase-scale migrations. Effort control (low/high/extra/max) lets you tune reasoning depth without paying a different per-token rate. Fast Mode is 3x cheaper than Opus 4.7's. Pricing still holds at $5 / $25 per million tokens.
Above Fable 5 sits Claude Mythos 5: the same underlying model with safeguards lifted, available only through "Project Glasswing" to infrastructure providers and vetted cybersecurity researchers. Not a general release.
Access the free tier at claude.ai (runs on Sonnet 4.6) or upgrade to Pro ($20/mo). Heads up: Fable 5 is included free in Pro/Max/Team and seat-based Enterprise plans through June 22, 2026. After June 23, it moves to usage credits. Available across all Claude products and the API, plus Amazon Bedrock, Google Vertex AI, GitHub Copilot, and Microsoft Foundry.
02
Key Capabilities
Mythos-Class Reasoning (Fable 5)
80.3% on SWE-bench Pro — leads Opus 4.8 (69.2%), GPT-5.5 (58.6%), and Gemini 3.1 Pro (54.2%) by double digits
Dynamic Workflows (Opus 4.8)
Research-preview feature: Claude plans the job, spawns hundreds of parallel subagents, verifies its own outputs. Built for codebase-scale migrations and audits.
Effort Control
Four levels — low, high, extra, max. Higher effort burns more tokens but stays at the same per-token rate. No surprise pricing tiers.
3x Cheaper Fast Mode (Opus 4.8)
Fast Mode pricing at $10 / $50 per million tokens — 3x cheaper than Opus 4.7's Fast Mode
High-Resolution Vision
High-res image support up to 2576px / 3.75MP. Big jump for design reviews, dense diagrams, and document analysis
Adaptive Thinking
Automatically adjusts reasoning depth — fast for simple tasks, deep for complex ones
Agent Teams (Swarms)
Orchestrate multiple Claude Code instances working in parallel on a project
Computer Use
Most accurate model for operating computers — navigates interfaces, fills forms, moves data across applications
1M Token Context (Beta)
Process entire codebases, legal documents, or research papers in a single conversation
128K Max Output (300K Beta)
128K standard, or up to 300K tokens via beta header (output-300k-2026-03-24)
Compaction
Automatic server-side context summarization when conversations approach the limit
Industry-Leading Coding
65.4% on Terminal-Bench 2.0 — state-of-the-art across coding benchmarks
14.5-Hour Task Horizon
Longest sustained task completion time of any AI model — built for marathon workloads
Long-Context Coherence
76% accuracy on MRCR v2 8-needle 1M variant
03
Pricing
| Tier | Price | Details |
|---|---|---|
| Free | $0 | Runs on Sonnet 4.6. Projects, Artifacts, app connectors. Tighter limits. |
| Pro | $20/mo ($17/mo annual) | ~5x free tier messages. Opus 4.8 access. Fable 5 free through June 22. |
| Max 5x | $100/mo | 25x free tier capacity. Fable 5 free through June 22. |
| Max 20x | $200/mo | 100x free tier capacity. Fable 5 free through June 22. |
| Team | $25-$30/user/mo | Collaboration features, admin controls. Fable 5 free through June 22. |
| Enterprise | Custom | SSO, audit logging, compliance APIs, enhanced context. |
| API — Fable 5 | $10 / $50 per 1M tokens | Mythos-class. Batch API at 50% off ($5 / $25). Cache hits at $1/M. |
| API — Opus 4.8 | $5 / $25 per 1M tokens | Standard. Fast Mode $10 / $50 (3x cheaper than 4.7's Fast Mode). |
| API — Sonnet 4.6 | $3 / $15 per 1M tokens | Mid-tier performance at lower cost. |
| API — Haiku 4.5 | $1 / $5 per 1M tokens | Fastest, most affordable. |
04
Best Use Cases
Complex software development and large codebase management
Long, sustained coding sessions and agentic coding tasks
Multi-application workflow automation via computer use
Enterprise document analysis — legal, financial, medical
Research tasks requiring long-context coherence across massive documents
Building AI-powered applications via the API
Tasks requiring safety, compliance, and governance
05
Pro Prompts
Codebase Analysis
Debug this large codebase and suggest refactors. Prioritize by impact-to-effort ratio. Flag any security concerns you spot.Dynamic Workflow (Opus 4.8)
Use Dynamic Workflows. Plan a codebase-wide migration from [old framework] to [new framework]. Spawn parallel subagents per package, run each through type-check and tests, then verify before reporting back.Mythos-Class Reasoning (Fable 5)
Set effort to max. This is the kind of problem that justifies the cost: [hard problem]. Take the time. Verify every step. I'd rather wait 5 minutes for a right answer than 30 seconds for a wrong one.Document Deep Dive
Analyze this 200-page contract. Extract every obligation, deadline, and liability clause. Flag anything that deviates from standard commercial terms.Computer Use
Navigate to [application], export the Q4 report as CSV, clean the data, and create a summary dashboard in Google Sheets.06
Limitations
Higher latency at high/max effort levels, especially on complex reasoning tasks
1M context window is beta-only with a 4% timeout error rate; standard is 200K
Spatial reasoning remains a common weakness
Agent Teams can occasionally duplicate work and burn through tokens quickly
Free tier does NOT include Fable 5 or Opus 4.8 — runs on Sonnet 4.6
Fable 5 is 2x the per-token cost of Opus 4.8 ($10/$50 vs $5/$25). Free in subscriptions only through June 22, 2026 — after that, usage credits.
Fable 5 ships with new safeguards that block responses in specific high-risk areas (cybersecurity, biology). Legitimate research can hit false positives.
Claude Mythos 5 (the unrestricted tier) is gated behind Project Glasswing — infrastructure providers and vetted cybersecurity researchers only
Can "overthink" simple tasks at default effort, adding unnecessary cost and latency
No native image generation — text and code output only
07
Multimodal Capabilities
Vision (Up to 3.75MP)
- High-res charts, graphs, technical diagrams
- Reports, screenshots, dense documents
- Max image input: 2576px / 3.75MP
Computer Use
- Desktop software operation
- GUI navigation and form filling
File Uploads
- PDFs and documents
- Spreadsheets and presentations
Output
- Text and code only
- No native image, audio, or video generation
08
Recent Updates
Jun 9, 2026
Claude Fable 5 generally available — first publicly accessible Mythos-class model. 80.3% SWE-bench Pro, $10/$50 API pricing. Free in Pro/Max/Team/Enterprise through Jun 22.
Jun 9, 2026
Claude Mythos 5 deployed via "Project Glasswing" — unrestricted version for infrastructure providers and vetted cybersecurity researchers
May 28, 2026
Opus 4.8 launched — Dynamic Workflows (parallel subagents), effort control, 3x cheaper Fast Mode, 69.2% SWE-bench Pro
Apr 16, 2026
Claude Opus 4.7 generally available — step-change agentic coding, high-res vision (3.75MP)
Feb 4, 2026
Opus 4.6 launched with Agent Teams, 1M context (beta), adaptive thinking, and compaction
Milestone
Available across all Claude products and the API, plus Amazon Bedrock, Google Vertex AI, GitHub Copilot, and Microsoft Foundry