tool-trim-compaction

1import type { Register } from 'claude-code';
2import { trimToolHistory } from './trim';
3
4const KEEP_RECENT_MESSAGES = 6;
5const MIN_REDUCTION = 0.25;
6const COMPACT_AT_PERCENT = 60;
7
8const pct = (r: number) => `${Math.round(r * 100)}%`;
9
10export const register: Register = (on) => {
11  let compacting = false;
12
13  on('session.compact', async ($, e, next) => {
14    if (e.trigger === 'precompute') return next(e);
15    let out;
16    try {
17      out = trimToolHistory(e.messages, KEEP_RECENT_MESSAGES);
18    } catch (error) {
19      $.ui.log(`tool-trim: failed (${error instanceof Error ? error.message : String(error)}); standard summary`);
20      return next(e);
21    }
22    if (out.reduction < MIN_REDUCTION) {
23      $.ui.log(`tool-trim: ${pct(out.reduction)} reduction, below ${pct(MIN_REDUCTION)}; standard summary`);
24      return next(e);
25    }
26    const line = `tool-trim: dropped ${out.dropped} tool calls, ${pct(out.reduction)} reduction, kept ${out.messages.length}/${e.messages.length} messages`;
27    $.ui.log(line);
28    $.ui.toast(line, { timeoutMs: 15_000 });
29    return { messages: out.messages };
30  });
31
32  // 標準の自動 compaction より早い 60% で切る。要約を作らないので、早めに切っても費用が増えない。
33  on('turn.complete', async ($, e, next) => {
34    if (compacting) return next(e);
35    try {
36      const { context } = await $.session.usage();
37      if ((context.percent ?? 0) >= COMPACT_AT_PERCENT) {
38        compacting = true;
39        await $.session.compact();
40      }
41    } catch (error) {
42      $.ui.log(`tool-trim: auto-compact skipped (${error instanceof Error ? error.message : String(error)})`);
43    } finally {
44      compacting = false;
45    }
46    return next(e);
47  });
48};
49

1import type { SessionMessage } from 'claude-code';
2
3export type TrimResult = {
4  messages: SessionMessage[];
5  dropped: number;
6  charsBefore: number;
7  charsAfter: number;
8  reduction: number;
9};
10
11function chars(m: SessionMessage): number {
12  let n = m.text.length;
13  for (const t of m.toolUses) n += JSON.stringify(t.input ?? {}).length + (t.text?.length ?? 0);
14  for (const r of m.toolResults ?? []) n += r.text.length;
15  return n;
16}
17
18// 先頭メッセージと直近 keepRecent 件にある呼び出しだけを残す。結果は呼び出しと組で扱い、
19// 呼び出しを消したら結果も消す（呼び出しの無い結果を API に渡すと拒否されるため）。
20export function trimToolHistory(input: readonly SessionMessage[], keepRecent: number): TrimResult {
21  const isPinned = (i: number) => i === 0 || i >= input.length - keepRecent;
22  const pinnedCalls = new Set<string>();
23  input.forEach((m, i) => {
24    if (isPinned(i)) for (const t of m.toolUses) pinnedCalls.add(t.tool_use_id);
25  });
26
27  let dropped = 0;
28  const messages: SessionMessage[] = [];
29  input.forEach((m) => {
30    const toolUses = m.toolUses.filter((t) => pinnedCalls.has(t.tool_use_id));
31    const toolResults = (m.toolResults ?? []).filter((r) => pinnedCalls.has(r.tool_use_id));
32    dropped += m.toolUses.length - toolUses.length;
33    if (toolUses.length === m.toolUses.length && toolResults.length === (m.toolResults ?? []).length) {
34      messages.push(m);
35      return;
36    }
37    if (!m.text.trim() && toolUses.length === 0 && toolResults.length === 0) return;
38    const rebuilt: SessionMessage = { role: m.role, text: m.text, toolUses };
39    if (toolResults.length > 0) rebuilt.toolResults = toolResults;
40    messages.push(rebuilt);
41  });
42
43  const charsBefore = input.reduce((n, m) => n + chars(m), 0);
44  const charsAfter = messages.reduce((n, m) => n + chars(m), 0);
45  return { messages, dropped, charsBefore, charsAfter, reduction: charsBefore ? 1 - charsAfter / charsBefore : 0 };
46}
47