elite-dev

1import type { EngineInterface, Register } from "claude-code";
2
3import { formatContextStatus } from "./context-status-format";
4
5let latest = 0;
6
7/**
8 * Reads the session's context usage and writes it to the status line. A failed read leaves the
9 * last line in place, so the hook chain is never held up by it. A refresh that a newer one has
10 * overtaken drops its write, so the newest reading wins.
11 */
12async function refreshContextStatus($: EngineInterface) {
13  const ticket = ++latest;
14  try {
15    const { context } = await $.session.usage();
16    if (ticket === latest) {
17      await $.ui.status(formatContextStatus(context));
18    }
19  } catch {
20    // keep the previous line
21  }
22}
23
24/**
25 * Refreshes the context status line on `session.start`, `session.compact`, and `turn.complete`,
26 * each after the rest of the hook chain has run, and on `prompt.submit` without awaiting it.
27 */
28export const register: Register = (on) => {
29  on("session.start", async ($, e, next) => {
30    const result = await next(e);
31    await refreshContextStatus($);
32
33    return result;
34  });
35
36  on("prompt.submit", async ($, e, next) => {
37    // Not awaited, so the usage read never delays the prompt.
38    void refreshContextStatus($);
39
40    return next(e);
41  });
42
43  on("session.compact", async ($, e, next) => {
44    const result = await next(e);
45    await refreshContextStatus($);
46
47    return result;
48  });
49
50  on("turn.complete", async ($, e, next) => {
51    const result = await next(e);
52    await refreshContextStatus($);
53
54    return result;
55  });
56};
57

1const number = new Intl.NumberFormat("en", { notation: "compact", maximumFractionDigits: 1 });
2/** Formats a count in compact English notation with a lowercase suffix: `84000` is `84k`. */
3const compact = (n: number): string => number.format(n).replace("K", "k");
4
5/**
6 * `ctx 42% 84k/200k`. A missing percent is derived from tokens and window. A missing reading is
7 * left out, never shown as zero: `ctx 200k` with no usage, `ctx` with nothing known.
8 */
9export const formatContextStatus = (c: {
10  tokens?: number;
11  window: number;
12  percent?: number;
13}): string => {
14  const { tokens, window } = c;
15  const percent =
16    c.percent ?? (tokens !== undefined && window > 0 ? (tokens / window) * 100 : undefined);
17  const head = percent === undefined ? "ctx" : `ctx ${Math.round(percent)}%`;
18
19  if (!(window > 0)) {
20    return head;
21  }
22  if (tokens === undefined) {
23    return percent === undefined ? `${head} ${compact(window)}` : head;
24  }
25
26  return `${head} ${compact(tokens)}/${compact(window)}`;
27};
28