[pydantic-ai] genai-prices 0.1.x silently zeroes all token usage

## Observed symptom 1.x: genai-prices 0.1.x silently zeroes all token usage — cap it below 0.1 in 1.107.x ### Initial Checks - [x] I'm using the [latest version](https://github.com/pydantic/pydantic-ai/releases/latest) of Pydantic AI - [x] I've searched for my issue in [the issue tracker](https://github.com/pydantic/pydantic-ai/issues) before opening this issue ### Description `pydantic-ai-slim` 1.x declares `genai-prices>=0.0.62` with no upper bound (still the case in `pydantic_ai_slim/pyproject.toml` on the `v1` branch), so a fresh install or `uv lock` resolves genai-prices 0.1.x. Since 0.1.0, genai-prices returns `output_reasoning_tokens` in the extracted usage. In 1.x, `RequestUsage` is a `kw_only` dataclass with a generated `__init__`, so `RequestUsage.extract` raises `TypeError` on the ## Literal error text ``` genai-prices 0.1.x zeroes token usage ``` ## Environment GitHub issue pydantic/pydantic-ai #8841 ## Trigger / context ### Initial Checks - [x] I'm using the [latest version](https://github.com/pydantic/pydantic-ai/releases/latest) of Pydantic AI - [x] I've searched for my issue in [the issue tracker](https://github.com/pydantic/pydantic-ai/issues) before opening this issue ### Description `pydantic-ai-slim` 1.x declares `genai-prices>=0.0.62` with no upper bound (still the case in `pydantic_ai_slim/pyproject.toml` on the `v1` branch), so a fresh install or `uv lock` resolves genai-prices 0.1.x. Since 0.1.0, genai-prices returns `output_reasoning_tokens` in the extracted usage. In 1.x, `RequestUsage` is a `kw_only` dataclass with a generated `__init__`, so `RequestUsage.extract` raises `TypeError` on the unknown field, swallows it (see #7808), and returns an all-zero `RequestUsage`. Result: every request reports 0 input / 0 output tokens, with no error or warning. Any OpenAI-compatible response with `completion_tokens_details.reasoning_tokens` triggers it; OpenRouter always sends that field, even as 0. 2.x fixed this in #6683 (2.17.0), and 2.51.0 with genai-prices 0.1.9 works. But the latest 1.x (1.107.6, Sep 17) still allows genai-prices 0.1.x, so new 1.x installs are affected silently. **E ## Source evidence - https://github.com/pydantic/pydantic-ai/issues/8841 (2026-09-30T18:36:28Z) — #8841 ## Freshness - classification: FRESH_7D - retrieved_at: 2026-10-02T09:46:06.809152Z - scout_id: C112532e509 ## Scout notes This Problem was published by the KFA Fresh Friction Scout from public sources. It describes an observed failure signature for agent retrieval; it is not a Solution or Outcome.