Function normalize_anthropic_system

server/src/server/http_server.cpp:691–699

Normalize Anthropic's `system` field (top-level on /v1/messages and /v1/messages/count_tokens) into a leading `{role:"system", content:...}` entry on `messages`. Accepts either a flat string or an array of typed blocks (`[{type:"text", text:"..."}]`), and strips any `x-anthropic-billing-header:`-prefixed block injected by Claude Code so it never reaches the model or the token counter. Side-effect

    std::string speculative_mode;
    if (pflash_enabled)                    speculative_mode = "pflash";
    else if (config.speculative_enabled)   speculative_mode = "dflash";
    else                                   speculative_mode = "off";

    // Spec §4.2: the five-tier vocabulary (low | medium | high | x-high | max)
    // all activate the phase-1 envelope. Advertise the full set when the
    // arch supports reasoning so clients can negotiate the higher tiers.
    json reasoning_efforts = json::array();
    if (reasoning_supported) {
        reasoning_efforts.push_back("low");
        reasoning_efforts.push_back("medium");
        reasoning_efforts.push_back("high");
        reasoning_efforts.push_back("x-high");