@sema-agent/core/dist/core/media-byte-cap.js

Stateless, task-oriented AI agent core

export const AGGREGATE_MEDIA_BUDGET_BYTES = 30 * 1024 * 1024;
const MEDIA_STRIPPED_MARKER = "[media removed to fit the request media budget — re-read the file if you still need to see it]";
function imageBytes(b) {
    return typeof b.data === "string" ? Math.floor((b.data.length * 3) / 4) : 0;
}
function blocksOf(m) {
    const content = m.content;
    return Array.isArray(content) ? content : undefined;
}
export function capAggregateMediaBytes(messages, opts) {
    const { limitBytes } = opts;
    if (!Number.isFinite(limitBytes) || limitBytes <= 0)
        return messages;
    let total = 0;
    for (const m of messages) {
        const blocks = blocksOf(m);
        if (blocks)
            for (const b of blocks)
                if (b.type === "image" || b.type === "document")
                    total += imageBytes(b);
    }
    if (total <= limitBytes)
        return messages;
    let remaining = total;
    let removedBytes = 0;
    let removedCount = 0;
    const out = messages.slice();
    for (let i = 0; i < out.length && remaining > limitBytes; i++) {
        const blocks = blocksOf(out[i]);
        if (!blocks)
            continue;
        let changed = false;
        const next = blocks.map((b) => {
            if (remaining > limitBytes && (b.type === "image" || b.type === "document")) {
                const bytes = imageBytes(b);
                remaining -= bytes;
                removedBytes += bytes;
                removedCount += 1;
                changed = true;
                return { type: "text", text: MEDIA_STRIPPED_MARKER };
            }
            return b;
        });
        if (changed)
            out[i] = { ...out[i], content: next };
    }
    if (removedCount > 0)
        opts.onStripped?.({ totalBytes: total, limitBytes, removedCount, removedBytes });
    return out;
}