There are three ways to get Claude-class models into Pi or oh-my-pi: an Anthropic API key (pay per token — Sonnet-class from $2/$10 per MTok, no windows, meter risk on agent loops), OAuth to a Claude Pro/Max subscription ($20–200/mo — subject to Anthropic's third-party agent conditions since the April 2026 policy turn), or a flat-rate routed API that serves Claude-family models among others from $19/mo. Pi is free and MIT-licensed either way — you are only ever paying for models.
| Route | Cost | Limits | The catch |
|---|---|---|---|
| Anthropic API key | Per token: Sonnet $2/$10, Opus $5/$25, Fable $10/$50 per MTok | None — just the meter | Agentic sessions burn 400K–2M tokens per task; bills spike |
| Claude Pro/Max OAuth | $20 / $100 / $200 per mo | 5-hour + weekly windows, shared with chat | Third-party agent access allowed only under Anthropic's conditions — policy changed once in 2026 already |
| Flat-rate smart routing | From $19/mo | Fixed monthly budget, no windows | Routes across Claude-family and other models — you do not pin one Claude version |
Pi (pi.dev, by badlogic) is a minimal open-source agent harness; oh-my-pi is its coding-first fork. Both connect to 15+ providers via API keys or OAuth — Anthropic, OpenAI, Google, OpenRouter, Ollama and more — so the model bill is a choice, not a default. That flexibility is exactly why the 'which subscription' question matters more for Pi users than for locked agents.
The OAuth route rides on Anthropic's tolerance, which has already flipped once in 2026 (ban in April, reinstatement with conditions). If your Pi setup is load-bearing, treat a chat-subscription backend as temporary convenience, not infrastructure.
Standard Compute supports Pi and oh-my-pi natively (both are first-class integrations): OpenAI-compatible endpoint, model standardcompute, flat plans from $19/mo. Smart routing serves Claude-family models alongside GPT-class, Gemini-class and efficient open models — frontier quality on the hard steps without a meter or a window.
Pi supports OAuth provider connections, but Anthropic's terms for third-party agent use of subscriptions changed in April 2026 and now apply conditions. Check the current policy before relying on it — the safer paths are an API key or a routed flat-rate API.
Light use with caching: often under $10–20/mo on Sonnet-class. Daily agentic use: $150–250/mo is the realistic band reported for sustained agent workloads on metered frontier APIs.
Free: Ollama or free-tier models. Cheap with real quality: an $18–20 coding plan or a flat-rate routed API from $19/mo. The split that works: flat plan for volume, pinned frontier key only if a specific task demands one exact model.