Follow a Run

curl --no-buffer \
    --url "https://www.crossmint.com/api/unstable/agent-checkouts/YOUR_RUN_ID/messages/stream" \
    --header "Accept: text/event-stream" \
    --header "X-API-KEY: YOUR_SERVER_API_KEY" \
    --header "x-crossmint-user-id: YOUR_USER_ID"

id: cursor_01
event: run.updated
data: {"runId":"...","revision":3,"status":"awaiting_input","requiredAction":{...}}

id: cursor_02
event: message.upsert
data: {"id":"msg_...","revision":2,"role":"assistant","parts":[...]}

// Uses BASE_URL, runId, and headers from the authentication section.
const messages = new Map();
let cursor: string | null = null;
let streamCursor: string | null = null;

do {
    const query = new URLSearchParams({ limit: "100" });
    if (cursor !== null) {
        query.set("cursor", cursor);
    }
    const response = await fetch(`${BASE_URL}/${runId}/messages?${query}`, { headers });
    if (!response.ok) {
        throw new Error(`Could not list messages: ${response.status}`);
    }
    const page = await response.json();
    for (const message of page.data) {
        const existing = messages.get(message.id);
        if (!existing || message.revision > existing.revision) {
            messages.set(message.id, message);
        }
    }
    cursor = page.nextCursor;
    streamCursor = page.streamCursor;
} while (cursor !== null);

const response = await fetch(`${BASE_URL}/${runId}`, { headers, cache: "no-store" });
if (!response.ok) {
    throw new Error(`Could not read checkout: ${response.status}`);
}
const run = await response.json();
const streamUrl = new URL(`${BASE_URL}/${runId}/messages/stream`);
if (streamCursor !== null) {
    streamUrl.searchParams.set("after", streamCursor);
}

// Uses BASE_URL, runId, and headers from the authentication section.
async function readRun() {
    const retryable = new Set([408, 429, 500, 502, 503, 504]);
    for (let attempt = 0; attempt < 5; attempt++) {
        let response: Response | undefined;
        try {
            response = await fetch(`${BASE_URL}/${runId}`, { headers, cache: "no-store" });
        } catch (error) {
            if (attempt === 4) {
                throw error;
            }
        }
        if (response?.ok) {
            return response.json();
        }
        if (response && (!retryable.has(response.status) || attempt === 4)) {
            throw new Error(`Could not read checkout: ${response.status}`);
        }
        const body = response?.status === 429 ? await response.json().catch(() => null) : null;
        const seconds = body?.retryAfterSeconds;
        const serverDelay = typeof seconds === "number" && Number.isFinite(seconds) && seconds > 0
            ? seconds * 1_000 : 0;
        await new Promise((resolve) => setTimeout(resolve, Math.max(1_000 * 2 ** attempt, serverDelay)));
    }
    throw new Error("Could not read checkout after retries");
}