/**
 * Vision capability + image-attachment detection.
 *
 * Two jobs:
 *   1. isVisionModel(id)        — does this gateway model accept image input?
 *   2. messageNeedsVision(text) — does this user message reference an image?
 *
 * Source of truth: a hand-curated allowlist below. The gateway exposes a
 * 'vision' category on /v1/models, but resolving it at routing time would
 * make routeRequest async and gate sync proxy paths on a network call. The
 * allowlist is small (~18 entries) and changes only when models do, which
 * already touches the router + pricing tables — updating one more file is
 * the right tradeoff vs. async fan-out across every routing callsite.
 *
 * Background: prior to this module, Auto routing could pick a text-only model
 * (e.g. deepseek-v4-pro) on an image-bearing turn. The Read tool would still
 * inline image bytes, the gateway would tokenize the base64 as text, and the
 * model — having no vision pathway — would hallucinate based on the
 * `Image file: <path>` description string. Expensive AND wrong.
 */
/** Does this concrete gateway model accept image input? */
export declare function isVisionModel(modelId: string | undefined | null): boolean;
/**
 * Pick a vision-capable replacement closest to the user's chosen model.
 * Prefers same provider family (so the user's intent — "I want Claude" vs
 * "I want Gemini" — survives the swap), then falls back to a sensible
 * vision default (Sonnet 4.6 — agent-tuned, mid-tier price).
 */
export declare function pickVisionSibling(modelId: string): string;
/**
 * Does this user-typed message reference an image file? Used by the router
 * to bump Auto mode to a vision-capable tier, and by the manual-mode guard
 * to swap a text-only model for one turn.
 *
 * Detection is intentionally a regex over file extensions rather than a
 * filesystem stat — the user may type a path that doesn't yet exist
 * (about to wget it) or a glob; what we care about is "does the model need
 * eyes for this turn?" The false-positive risk is benign (we route to a
 * slightly stronger model than strictly needed).
 */
export declare function messageNeedsVision(text: string | undefined | null): boolean;
/**
 * Messages-array variant: scans OpenAI- and Anthropic-format content blocks
 * for explicit image parts (image / image_url / input_image) and for image
 * paths embedded in text parts. Used by the proxy router which receives a
 * fully-formed messages[] payload, not a single string.
 */
export declare function messagesNeedVision(messages: Array<{
    role?: string;
    content?: unknown;
}> | undefined | null): boolean;