Prompt caching

import routehub

policy_handbook = open("handbook.md").read()

messages = [
    {
        "role": "system",
        "content": [
            {
                "type": "text",
                "text": policy_handbook,
                "cache_control": {"type": "ephemeral"},
            }
        ],
    },
    {"role": "user", "content": "Which policies cover vendor onboarding?"},
]

response = routehub.completion(model="claude-sonnet-4-6", messages=messages)

details = response.usage.prompt_tokens_details
print(details.cached_tokens if details else 0)        # tokens read from cache
print(response.usage.cache_creation_input_tokens)     # tokens written to cache

routehub.supports_prompt_caching("claude-sonnet-4-6")               # True
routehub.supports_prompt_caching("openrouter/anthropic/claude-sonnet-4.6")  # True
routehub.supports_prompt_caching("gpt-5.4-mini")                    # False