[action] Claude Sonnet 5 introductory pricing ends; standard rates take effect

Claude Sonnet 5 launched with introductory pricing of $2/$10 per Mtok (input/output) through August 31, 2026. From September 1, 2026 standard pricing of $3/$15 per Mtok applies — a 50% increase (cache write $3.75, read $0.30). Effective: 2026-09-01. Affected: anthropic/claude-sonnet-5. Severity: action_required. Verification: verified.