Claude Opus 5.5: Release Date, Pricing & How to Use It
Explore Claude Opus 5.5 release details, pricing, 1M-token context, adaptive thinking, and key API changes, plus a first-use example on Modellix.
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Claude Fable Price: Fable 5.1 at $10/$50 per 1M Tokens
Claude Fable price as of Sept 4, 2026: Fable 5.1 bills $10/$50 per 1M tokens at Anthropic, $9/$45 on Modellix (10% OFF); cache reads cost $0.225 per million.
Claude API Pricing (2026): Opus 5, Sonnet 5, Haiku 4.5 Costs
Claude API pricing as of Sept 3, 2026: per-million-token rates for Opus 5, Sonnet 5, and Haiku 4.5, plus flat-rate billing, cache pricing, and context windows.
Anthropic Base URL: Claude Code and Harness, No /v1
Set ANTHROPIC_BASE_URL to https://llm.modellix.ai, never /v1: Claude Code settings.json and the harness anthropic-messages provider, plus the 401 auth traps.
Claude Fable 5.1 vs Opus 5: Run Cost, Not Benchmarks
Fable 5.1 output is ~2x Opus 5 ($45 vs $22.50/1M, Sep 4, 2026); cache reads are half. Cheaper depends on workload shape; decide by scenario, verify on bills.