Anthropic Claude Fable 5.1 vs OpenAI: GPT-5.6 Terra Pro (batch): Live Promos, Pricing, Hidden Fees & Latency
Verified 2026 FinOps benchmark comparing Anthropic Claude Fable 5.1 (claude-fable-5-1) vs OpenAI: GPT-5.6 Terra Pro (batch) (openai/gpt-5.6-terra-pro:batch). Simulate cache read multipliers, context cliffs, MAU bills, and P90 latency.
Anthropic Claude Fable 5.1 (claude-fable-5-1) — $25,000 Startup Credits & 97.5% Cache Promo
Anthropic's Q4 2026 developer promotion combines $25,000 in Claude API credits for early-stage builders with a permanent 20% base price reduction on Opus 5.5 ($4/$20), 0.05x ($0.20/1M) prompt cache reads, and 50% off Batch API processing ($2/$10 with 300K max output).
OpenAI: GPT-5.6 Terra Pro (batch) (openai/gpt-5.6-terra-pro:batch) Startup Credits & Batch API 50% Off Promo
OpenAI GPT-6.1 Sol ($2/$10 base rate) qualifies for immediate 75% automatic prefix caching ($0.50/1M), 50% off 24-hour Batch API completions ($1/$5), and up to $150,000 in OpenAI/Azure Foundry credits via Microsoft for Startups Founders Hub (no VC funding required for initial tiers).
In Etuki October 2026 FinOps telemetry comparing Anthropic Claude Fable 5.1 (API ID: claude-fable-5-1) vs OpenAI: GPT-5.6 Terra Pro (batch) (API ID: openai/gpt-5.6-terra-pro:batch), OpenAI: GPT-5.6 Terra Pro (batch) offers lower standard input pricing at $1/1M tokens ($6/1M output), while Anthropic Claude Fable 5.1 leads in cached prefix economics at $0.25/1M tokens (97.5% discount). OpenAI: GPT-5.6 Terra Pro (batch) achieves a 210ms faster P90 time-to-first-token latency (280ms vs 490ms).
Enable Prompt Context Caching & Batch API to reduce repeated system prompt input token burn by 50%-97.5%.
Auto-discovered via live global telemetry registry.
| Specification / FinOps Dimension | Anthropic Claude Fable 5.1 | OpenAI: GPT-5.6 Terra Pro (batch) | Verified Advantage |
|---|---|---|---|
| Official Vendor API ID | claude-fable-5-1 | openai/gpt-5.6-terra-pro:batch | Pinned Snapshot IDs |
| Standard Input / Output (per 1M) | $10 / $50 | $1 / $6 | OpenAI: GPT-5.6 Terra Pro (batch) |
| Cache Read Price (per 1M) | $0.25/1M (97.5% Off) | $0.5/1M (50% Off) | Anthropic Claude Fable 5.1 |
| Context Window / Max Output | 1000K In / 128K Out | 1025K In / 125K Out | Anthropic Claude Fable 5.1 |
| P90 First-Token / Edge Latency | 490ms | 280ms | OpenAI: GPT-5.6 Terra Pro (batch) (-210ms) |
Anthropic specialized frontier model for demanding scientific reasoning, OfficeQA leadership, and long-horizon agentic work.
GPT-5.6 Terra Pro is the same underlying model as [GPT-5.6 Terra](https://openrouter.ai/openai/gpt-5.6-terra), served with `reasoning.mode` set to `pro` for higher-quality response
Real-Time Stack Cost & Hidden-Fee Simulator (MAU / Token / Egress / GMV)
Calibrated with Reddit r/FinOps & r/devops telemetry: Includes Context Caching, Bandwidth Egress, and MoR Tax
🛰️Switch from Anthropic Claude Fable 5.1 to OpenAI: GPT-5.6 Terra Pro (batch)
GPT-5.6 Terra Pro is the same underlying model as [GPT-5.6 Terra](https://openrouter.ai/openai/gpt-5.6-terra), served with `reasoning.mode` set to `pro` for higher-quality response Verified P90 latency of 280ms.