Vercelfeature 92% Confidence Gate September 22, 2026

Vercel AI Gateway Adds Support for Anthropic Claude Opus 5.5

Vercel AI Gateway now supports Anthropic Claude Opus 5.5, which offers 30% faster performance and 40% lower costs compared to Opus 5. The update introduces breaking API changes including mandatory adaptive thinking and the deprecation of forced tool use.

Verified State Diff

Comparison Mode:

- Previous State

Support for Claude Opus 5 with manual control over thinking budgets and the ability to force tool calls.

+ Verified New State

Support for Claude Opus 5.5 with mandatory adaptive thinking, retired forced tool use, and new model identifiers 'anthropic/claude-opus-5.5' and 'anthropic/claude-opus-5.5-fast'.

Impact & Verification Analysis

WHO IS AFFECTED

Developers using Vercel AI Gateway for Anthropic model inference and coding agents.

WHY IT MATTERS

The update provides significant cost and performance gains for agentic workflows while forcing a migration away from legacy tool-calling patterns to structured outputs.

Full Fact Overview

Vercel has integrated Anthropic's Claude Opus 5.5 into its AI Gateway, accessible via the 'anthropic/claude-opus-5.5' model identifier. This release includes a 'fast' mode variant ('anthropic/claude-opus-5.5-fast'), a 1M-token context window, and a June 2026 knowledge cutoff. Developers must update their integrations to accommodate two breaking changes: the model now mandates adaptive thinking (disabling fixed thinking budgets) and has retired forced tool use, requiring developers to shift to structured outputs for JSON enforcement.

Multi-Source Evidence Chain (1)

Claude Opus 5.5 now available on AI Gatewayhttps://vercel.com/changelog

TRACKED ENTITY

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