tldr

1import type { EngineInterface, Register } from 'claude-code'
2
3import { clean, promptFor, SYSTEM, wordCount } from './tldr'
4
5// Whether long answers get a TL;DR on their own; /tldr on|off keeps it in $.store.
6let isAuto = true
7// A -p run prints the answer alone, so a TL;DR there would cost a call nobody sees.
8let isHeadless = false
9
10/** One `TL;DR: …` line for `answer`, or undefined when the model gave none. */
11async function summarize($: EngineInterface, answer: string, model: string): Promise<string | undefined> {
12  const reply = await $.model
13    .complete({ model, system: SYSTEM, prompt: promptFor(answer), maxTokens: 120, effort: 'low', timeoutMs: 15_000 })
14    .catch(() => undefined)
15  if (reply === undefined || !reply.isAnswered) return undefined
16  const line = clean(reply.text)
17  return line === '' ? undefined : `TL;DR: ${line}`
18}
19
20async function setAuto($: EngineInterface, value: boolean): Promise<void> {
21  isAuto = value
22  await $.store.set('auto', value)
23}
24
25/** The last answer Claude gave in this conversation, or '' before the first. */
26async function lastAnswer($: EngineInterface): Promise<string> {
27  const messages = await $.session.messages()
28  for (let i = messages.length - 1; i >= 0; i--) {
29    const message = messages[i]
30    if (message?.role === 'assistant' && message.text.trim() !== '') return message.text
31  }
32  return ''
33}
34
35export const register: Register = (on, options) => {
36  const minWords = Math.max(1, Number(options.minWords ?? 200))
37  const model = String(options.model ?? 'haiku')
38
39  on('session.start', async ($, e, next) => {
40    isAuto = (await $.store.get('auto')) !== false
41    isHeadless = !e.isInteractive
42    try {
43      await $.command.register({
44        name: 'tldr',
45        description: 'TL;DR of the last answer, or turn the automatic one on/off',
46        argumentHint: '[on | off | status]',
47      })
48    } catch (error) {
49      $.ui.log(`tldr: could not add /tldr: ${String(error)}`, { to: 'debug' })
50    }
51    return next(e)
52  })
53
54  on('turn.complete', async ($, e, next) => {
55    const result = await next(e)
56    const isEligible = isAuto && !isHeadless && e.agentId === undefined && e.reason === 'answer' && !e.isAborted
57    if (!isEligible || wordCount(e.answer) < minWords) return result
58
59    const line = await summarize($, e.answer, model)
60    if (line === undefined) return result
61    // A text other than the answer is shown beneath it; keep another mod's line too.
62    return { ...result, text: result.text === e.answer ? line : `${result.text}\n${line}` }
63  })
64
65  on('command.run', { command: 'tldr' }, async ($, e) => {
66    const word = e.args.trim().toLowerCase()
67    if (word === 'on' || word === 'off') {
68      await setAuto($, word === 'on')
69      return { text: word === 'on' ? `tldr is on: answers of ${minWords}+ words get a one-line TL;DR.` : 'tldr is off. /tldr still summarizes the last answer on demand.' }
70    }
71    if (word === 'status') {
72      return { text: `tldr is ${isAuto ? 'on' : 'off'}: answers of ${minWords}+ words get a TL;DR from ${model}.` }
73    }
74    if (word !== '') return { text: 'Usage: /tldr (summarize the last answer) · /tldr on · /tldr off · /tldr status' }
75
76    const answer = await lastAnswer($)
77    if (answer === '') return { text: 'Nothing to summarize yet.' }
78    return { text: (await summarize($, answer, model)) ?? `tldr: ${model} gave no summary; try again.` }
79  })
80}
81

1// Pure helpers: no `$`, so tests import them directly.
2
3export const SYSTEM =
4  "You write TL;DR lines. Given an AI coding assistant's answer, reply with ONE plain sentence of at most 25 words " +
5  'that tells a developer skimming a terminal the outcome: what was found, done, decided or recommended. ' +
6  'No markdown, no preamble, no quotes, no "TL;DR" label.'
7
8const FENCE = /```[\s\S]*?(```|$)/g
9
10/** Words of prose: fenced code blocks don't count. */
11export function wordCount(text: string): number {
12  return text.replace(FENCE, ' ').split(/\s+/).filter(word => /[\p{L}\p{N}]/u.test(word)).length
13}
14
15/** The answer as the summarizer reads it: long ones keep their head and their end. */
16export function promptFor(answer: string): string {
17  const body = answer.length > 16_000 ? `${answer.slice(0, 12_000)}\n[…]\n${answer.slice(-4_000)}` : answer
18  return `Write the TL;DR of this answer.\n\n<answer>\n${body}\n</answer>`
19}
20
21/** One clean line from whatever the model wrote, or '' when nothing usable came back. */
22export function clean(reply: string): string {
23  const line = reply
24    .replace(/^\s*(\*\*)?\s*(tl;?dr|summary)\s*[:\-–—]\s*(\*\*)?/i, '')
25    .replace(/[*_`#>]/g, '')
26    .split('\n')
27    .map(part => part.trim())
28    .find(part => part !== '') ?? ''
29  const flat = line.replace(/\s+/g, ' ').replace(/^["“']|["”']$/g, '').trim()
30  return flat.length > 280 ? `${flat.slice(0, 279).trimEnd()}…` : flat
31}
32