task-anchor

1import { atom, read, update } from 'claude-code'
2import type { EngineInterface, Register } from 'claude-code'
3
4const goal = atom({ plugin: 'task-anchor', key: 'goal' } as const, null)
5const focus = atom({ plugin: 'task-anchor', key: 'focus' } as const, 1)
6const offStreak = atom({ plugin: 'task-anchor', key: 'offStreak' } as const, 0)
7const isHidden = atom({ plugin: 'task-anchor', key: 'isHidden' } as const, false)
8
9const DRIFT_BELOW = 0.3
10const MIN_WORDS = 3
11const MIN_GOAL_WORDS = 4 // a casual line ("on est bon") is not a goal
12const STOP = new Set(
13  ('le la les un une des de du et ou en au aux ce ces cet cette que qui quoi dont pour par sur dans avec sans est sont ' +
14    'etre avoir fait faire peux peut veux vas ton ta tes mon ma mes son sa ses nous vous ils elles pas plus mais donc ' +
15    'the a an and or of to in on for with is are be do does can you your my it this that these those not but so ' +
16    'please merci stp bon ok oui non alors aussi comme tout tous toute very just').split(' '),
17)
18
19// Crude lexical proxy for "is this prompt about the goal": keyword sets, accents folded,
20// plural/suffix trimmed. Real semantic distance would need embeddings the mod cannot reach.
21const keywords = (text: string): Set<string> =>
22  new Set(
23    text
24      .toLowerCase()
25      .normalize('NFD')
26      .replace(/[̀-ͯ]/g, '')
27      .split(/[^a-z0-9_.\/-]+/)
28      .filter(w => w.length > 2 && !STOP.has(w))
29      .map(w => w.replace(/(s|x)$/, '')),
30  )
31
32// Levenshtein distance, abandoned as soon as it must exceed `max`.
33const within = (a: string, b: string, max: number): boolean => {
34  if (Math.abs(a.length - b.length) > max) return false
35  let prev = Array.from({ length: b.length + 1 }, (_, j) => j)
36  for (let i = 1; i <= a.length; i++) {
37    const cur = [i]
38    let low = i
39    for (let j = 1; j <= b.length; j++) {
40      const v = Math.min(prev[j] + 1, cur[j - 1] + 1, prev[j - 1] + (a[i - 1] === b[j - 1] ? 0 : 1))
41      cur.push(v)
42      if (v < low) low = v
43    }
44    if (low > max) return false
45    prev = cur
46  }
47  return prev[b.length] <= max
48}
49
50// Typos: one edit from 5 letters up, two from 9, none for short words (too many false hits).
51const similar = (w: string, set: Set<string>): boolean => {
52  if (set.has(w)) return true
53  const max = w.length >= 9 ? 2 : w.length >= 5 ? 1 : 0
54  if (max === 0) return false
55  for (const o of set) if (o[0] === w[0] && within(w, o, max)) return true
56  return false
57}
58
59const overlap = (a: Set<string>, b: Set<string>): number => {
60  if (a.size === 0 || b.size === 0) return 0
61  let hits = 0
62  for (const w of a) if (similar(w, b)) hits += 1
63  return hits / Math.min(a.size, b.size)
64}
65
66const bar = (v: number): string => {
67  const n = Math.round(Math.max(0, Math.min(1, v)) * 5)
68  return '●'.repeat(n) + '○'.repeat(5 - n)
69}
70
71// Words of the goal plus words of prompts judged on-topic, so the topic can evolve
72// slowly inside the goal's scope instead of being frozen to its first sentence.
73let topic = new Set<string>()
74let goalWords = new Set<string>()
75
76async function setGoal($: EngineInterface, text: string) {
77  goalWords = keywords(text)
78  topic = new Set(goalWords)
79  await update($, goal, () => text)
80  await update($, focus, () => 1)
81  await update($, offStreak, () => 0)
82}
83
84export const register: Register = on => {
85  on('session.start', async ($, e, next) => {
86    await $.command.register({
87      name: 'anchor',
88      description: 'Set, show or clear the session goal (/anchor <goal> | /anchor clear)',
89    })
90    return next(e)
91  })
92
93  on('command.run', { command: 'anchor' }, async ($, e) => {
94    const arg = e.args.trim()
95    if (arg === 'clear') {
96      await update($, goal, () => null)
97      return { text: 'goal cleared.' }
98    }
99    if (arg === '') {
100      const g = await read($, goal)
101      return { text: g === null ? 'no goal yet. /anchor <goal>' : `goal: ${g}` }
102    }
103    await setGoal($, arg)
104    return { text: 'goal set. I will watch for drift.' }
105  })
106
107  on('prompt.submit', async ($, e, next) => {
108    if (e.command || e.isMeta) return next(e)
109
110    const g = await read($, goal)
111    if (g === null) {
112      // the first substantial prompt defines the session's goal; chit-chat before it is ignored
113      if (keywords(e.text).size >= MIN_GOAL_WORDS) await setGoal($, e.text.slice(0, 300))
114      return next(e)
115    }
116
117    const words = keywords(e.text)
118    if (words.size < MIN_WORDS) return next(e) // "oui", "ok vas-y": neutral, no signal
119
120    const score = Math.max(overlap(words, goalWords), overlap(words, topic))
121    const prev = await read($, focus)
122    const next_ = 0.6 * prev + 0.4 * Math.min(1, score * 1.5)
123    await update($, focus, () => next_)
124
125    if (score >= 0.3) {
126      for (const w of words) topic.add(w)
127      await update($, offStreak, () => 0)
128    } else {
129      const n = (await read($, offStreak)) + 1
130      await update($, offStreak, () => n)
131      if (next_ < DRIFT_BELOW && n >= 2) {
132        $.ui.toast(`Dérive: ${n} prompts hors du but. /anchor pour redéfinir ou continuer.`)
133      }
134    }
135    return next(e)
136  })
137
138  // Counterweight: the goal is restated in the system prompt, sharper once drift is flagged.
139  on('prompt.compose', async ($, e, next) => {
140    const res = await next(e)
141    const g = await read($, goal)
142    if (g === null) return res
143
144    const drifting = (await read($, focus)) < DRIFT_BELOW
145    const text = drifting
146      ? `Session goal: "${g}". The conversation appears to have drifted from it. Before continuing, state briefly how the current request relates to the goal, or ask the user whether the goal has changed.`
147      : `Session goal: "${g}". Keep work aligned with it; flag it if a request leaves its scope.`
148    return { sections: [...res.sections, { id: 'task-anchor:goal', text, scope: 'session' as const }] }
149  })
150
151  on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
152    const g = await read($, goal)
153    if (e.props.hasSurvey || g === null || (await read($, isHidden))) return next(e)
154
155    const f = await read($, focus)
156    const { Box, Button, Text } = $.ui.resolve(e)
157    return (
158      <Box>
159        <Text dimColor={f >= DRIFT_BELOW} color={f < DRIFT_BELOW ? 'yellow' : undefined}>
160          But: {g.slice(0, 60)}
161          {g.length > 60 ? '…' : ''} · focus {bar(f)}{' '}
162        </Text>
163        <Button key="hide" label="Hide" onPress={() => update($, isHidden, () => true)} />
164      </Box>
165    )
166  })
167}
168

1export type Focus = number
2
3declare module 'claude-code' {
4  interface PluginState {
5    'task-anchor': {
6      goal: string | null
7      focus: Focus
8      offStreak: number
9      isHidden: boolean
10    }
11  }
12}
13