prompt cachingPrompt Caching Savings: One Timestamp Turns 80% Into 6%
On a 30-turn agent loop, prompt caching saves 80-89% depending on the provider, not 90%. A timestamp in the system prompt drops Claude's saving to 6%, and a volatile tool definition makes caching cost more than not caching.
October 1, 2026 · 17 min readlong context vs RAGLong Context vs RAG Cost: Cached, Each Answer Still Costs 5x
Prompt caching cuts a 400K-token long-context answer to $0.085 on Claude Sonnet 5.5, but RAG still answers for $0.017. The crossover formula, the accuracy-at-depth evidence and the latency users notice.
October 1, 2026 · 14 min readGemini 4 ArgonGemini 4 Argon Leads Vals at $15.68 a Task With No GA Date
Gemini 4 Argon tops the Vals Index at $15.68 per test, cheaper than Claude Sonnet 5.5 and Opus 5.5 even at its $4/$20 standard price. But access is limited to Fairwind security teams and trusted testers, with no GA date.
September 30, 2026 · 7 min readGPT-6.1 SolGPT-6.1 Sol's $5.47 Task Scores 11 Points Below Astra's $23.80
GPT-6.1 Sol costs a fifth of GPT-6 Astra per token and ties it on coding, but trails it by 11 points on Terminal-Bench Science. It still wins on cost per solved task — if your failures are cheap.
September 29, 2026 · 8 min read