fix: Update Claude Sonnet 5.5 pricing - #9035

Summary

Updates first-party Claude Sonnet 5.5 cache-read pricing from $0.20 to $0.10 / MTok, matching the reported 50% drop.

Changes

• providers/anthropic/models/claude-sonnet-5-5.toml:
  • [cost] cache_read: 0.2 → 0.1
  • Added leading header sources for the new value: https://platform.claude.com/docs/en/about-claude/pricing and https://www.anthropic.com/pricing
  • No other fields changed (input = 2, output = 10, cache_write = 2.5, reasoning_options unchanged).

Evidence

• https://www.anthropic.com/pricing — Latest models section lists Sonnet 5.5 as Input $2 / MTok, Output $10 / MTok, Prompt caching Read $0.10 / MTok, Write $2.50 / MTok. Establishes new $0.10 cache-read price.
• https://platform.claude.com/docs/en/about-claude/pricing — Prompt caching section states: “Cache read (hit) 0.1x base input price (0.025x on Claude Fable 5.1 and Claude Mythos 5.1; 0.05x on Claude Opus 5.5 and Claude Sonnet 5.5)” and “On Claude Opus 5.5 and Claude Sonnet 5.5, a cache hit costs 5% … ($0.20 USD per million tokens on Claude Opus 5.5, $0.10 USD on Claude Sonnet 5.5).” Establishes $0.10 = 5% × $2 for Sonnet 5.5.
• https://platform.claude.com/docs/en/models/sonnet-5-5/overview — Still shows Cache read $0.20 / MTok in its Pricing table. Not used as evidence for the change; noted as stale/inconsistent below.

Validation

• Read models/anthropic/claude-sonnet-5-5.toml to confirm lab file carries no cost (cost lives on provider files, so no lab edit needed).
• Read and edited only providers/anthropic/models/claude-sonnet-5-5.toml; verified edit preserved base_model, reasoning_options, and other cost keys.
• Verified new value against the two first-party sources above via fetch/search. Did not run bun validate or any shell commands.

Review notes

• First-party docs are currently inconsistent during rollout: the detailed prompt-caching text on /about-claude/pricing and anthropic.com/pricing say $0.10, while the model-pricing table on the same /about-claude/pricing page and the /models/sonnet-5-5/overview page still say $0.20. I followed the more specific multiplier text + marketing pricing page and the issue report.
• Intentionally left out mirrored cache_read = 0.2 entries on relays/cloud hosts (OpenRouter, Bedrock global./us./eu./anthropic., Vertex, Vercel, Azure, etc.). Each host needs its own authoritative pricing verification before changing; e.g. OpenRouter still lists $0.20 cache read.

Closes #9034

Automated by the issue fixer: https://github.com/anomalyco/models.dev/actions/runs/37672239138