Anthropic makes 1M token context window generally available for Opus 4.6 and Sonnet 4.6 — no beta header, standard pricing

Anthropic moved the 1M token context window to general availability for Claude Opus 4.6 and Sonnet 4.6 on March 13, removing the beta header requirement for requests over 200k tokens. Standard account rate limits now apply at all context lengths — the previous dedicated 1M rate limits are removed. Anthropic also raised the media limit from 100 to 600 images or PDF pages per request at 1M context. The 1M context window remains in beta for Claude Sonnet 4.5 and earlier models.

Removing the beta header is the structural change that matters most for developers. Beta headers signal that a feature can change without notice, can behave inconsistently, and shouldn't be used in production systems. GA means it's a stable, contractually-supported capability. Enterprise procurement, compliance review, and vendor approvals are triggered by that distinction — many organizations cannot deploy beta-flagged API features in customer-facing products.