session-topics

1import { atom, read, update } from 'claude-code'
2import type { EngineInterface, Register } from 'claude-code'
3
4import type { Saved } from '../types'
5
6const topics = atom({ plugin: 'session-topics', key: 'topics' } as const, [])
7const seed = atom({ plugin: 'session-topics', key: 'seed' } as const, null)
8const isMinimized = atom({ plugin: 'session-topics', key: 'isMinimized' } as const, false)
9
10const STORE_KEY = 'recent'
11const KEEP_SESSIONS = 50
12const MAX_TOPICS = 5
13const MINI_WIDTH = 24
14const RESUME_MESSAGES = 8
15
16// Readable on a dark or a light theme. Each session gets one, picked by its id,
17// so two sessions on the same subject still look different.
18const PALETTE = ['#e06c75', '#e5c07b', '#98c379', '#56b6c2', '#61afef', '#c678dd', '#d19a66', '#ff79c6']
19
20const SYSTEM = `You keep a short list of the topics a person worked on in one Claude Code session. The list helps them tell several terminals apart at a glance.
21
22Rules:
23- Each topic is 1 to 4 words and names the concrete subject (a feature, file, bug, page or tool). No trailing punctuation.
24- Keep the existing topics, in order. If the new messages continue the latest topic, you may sharpen its wording.
25- Add a topic at the end only when the messages start a clearly different subject.
26- Keep at most ${MAX_TOPICS} topics. Past that, merge the oldest two.
27- Messages with no subject ("yes", "continue", "thanks") leave the list as it is.
28- Write each topic in English, whatever language the messages use.
29
30Reply with the JSON array of strings only, oldest topic first.`
31
32function colorFor(id: string): string {
33  let hash = 2166136261
34  for (let i = 0; i < id.length; i++) hash = Math.imul(hash ^ id.charCodeAt(i), 16777619)
35  return PALETTE[(hash >>> 0) % PALETTE.length] ?? '#61afef'
36}
37
38function clip(text: string, width: number): string {
39  if (width <= 0) return ''
40  return text.length <= width ? text : `${text.slice(0, Math.max(0, width - 1))}…`
41}
42
43// A slash command counts by its arguments alone: `/goal build X` is about X.
44// The desktop puts a system reminder in front of the first prompt; it is no topic.
45function subjectOf(text: string): string {
46  const trimmed = text.replace(/<system-reminder>[\s\S]*?<\/system-reminder>/g, '').trim()
47  return trimmed.startsWith('/') ? trimmed.replace(/^\/\S*\s*/, '').trim() : trimmed
48}
49
50function seedOf(subject: string): string {
51  return clip(subject.split(/\s+/).slice(0, 6).join(' '), 40)
52}
53
54function parseTopics(reply: string): string[] | null {
55  const start = reply.indexOf('[')
56  const end = reply.lastIndexOf(']')
57  if (start < 0 || end <= start) return null
58  try {
59    const value: unknown = JSON.parse(reply.slice(start, end + 1))
60    if (!Array.isArray(value)) return null
61    const list = value
62      .filter((t): t is string => typeof t === 'string')
63      .map(t => clip(t.trim().replace(/[.!]+$/, ''), 40))
64      .filter(t => t.length > 0)
65      .slice(-MAX_TOPICS)
66    return list.length > 0 ? list : null
67  } catch {
68    return null
69  }
70}
71
72async function ask($: EngineInterface, current: string[], messages: string[]): Promise<string[] | null> {
73  const prompt = [
74    `Topics so far, oldest first: ${JSON.stringify(current)}`,
75    'Newest messages from the person, oldest first:',
76    ...messages.map(m => `<message>\n${m.slice(0, 1500)}\n</message>`),
77    'Reply with the updated JSON array.',
78  ].join('\n\n')
79  const reply = await $.model.complete({ model: 'haiku', system: SYSTEM, prompt, maxTokens: 200, timeoutMs: 30_000 })
80  return reply.isAnswered ? parseTopics(reply.text) : null
81}
82
83async function loadAll($: EngineInterface): Promise<Record<string, Saved>> {
84  const value = await $.store.get(STORE_KEY)
85  return value !== null && typeof value === 'object' ? (value as Record<string, Saved>) : {}
86}
87
88// Kept per session id, so a resumed session shows its topics with no model call.
89async function save($: EngineInterface, list: string[]) {
90  const all = await loadAll($)
91  all[await $.session.id()] = { topics: list, at: await $.clock.now() }
92  const newest = Object.entries(all)
93    .sort((a, b) => b[1].at - a[1].at)
94    .slice(0, KEEP_SESSIONS)
95  await $.store.set(STORE_KEY, Object.fromEntries(newest))
96}
97
98// Module variables: a reload drops them, and the topics in $.state stay.
99let queue: string[] = []
100let isBusy = false
101let generation = 0
102
103async function drain($: EngineInterface) {
104  if (isBusy) return
105  isBusy = true
106  try {
107    while (queue.length > 0) {
108      const started = generation
109      const batch = queue.splice(0, queue.length)
110      const list = await ask($, await read($, topics), batch)
111      // A /clear while the model answered: that answer is about the old session.
112      if (list && started === generation) {
113        await update($, topics, () => list)
114        await save($, list)
115      }
116    }
117  } catch {
118    // A failed call leaves the topics as they were; the next prompt tries again.
119  } finally {
120    isBusy = false
121  }
122}
123
124// The model call runs on a timer of its own, so no prompt waits for it.
125function enqueue($: EngineInterface, messages: string[]) {
126  queue.push(...messages)
127  $.clock.after(0, () => void drain($))
128}
129
130async function reset($: EngineInterface) {
131  generation += 1
132  queue = []
133  await update($, topics, () => [])
134  await update($, seed, () => null)
135}
136
137export const register: Register = on => {
138  on('session.start', async ($, e, next) => {
139    const result = await next(e)
140    // A reload fires session.start again; the session's topics are still in $.state.
141    if ((await read($, topics)).length > 0) return result
142
143    const saved = (await loadAll($))[await $.session.id()]
144    if (saved && saved.topics.length > 0) {
145      await update($, topics, () => saved.topics)
146      return result
147    }
148
149    const earlier = (await $.session.messages())
150      .filter(m => m.role === 'user' && !m.text.trimStart().startsWith('<'))
151      .map(m => subjectOf(m.text))
152      .filter(s => s.length > 0)
153    if (earlier.length > 0) enqueue($, earlier.slice(-RESUME_MESSAGES))
154
155    return result
156  })
157
158  // Only what the person typed: a plugin's or a peer's prompt is no topic of theirs.
159  on('prompt.submit', async ($, e, next) => {
160    if (e.origin.kind === 'composer' || e.origin.kind === 'bridge') {
161      const subject = subjectOf(e.text)
162      if (subject.length > 0) {
163        if ((await read($, seed)) === null) await update($, seed, () => seedOf(subject))
164        enqueue($, [subject])
165      }
166    }
167
168    return next(e)
169  }).catch(($, e, next) => next(e))
170
171  // No session.start follows a /clear, so the list starts over here.
172  on('session.end', async ($, e, next) => {
173    if (e.reason === 'clear') await reset($)
174
175    return next(e)
176  })
177
178  on('ui.render', { component: 'AbovePrompt' }, async ($, e, next) => {
179    // What other plugins drew in the band: drawn under this row, never replaced.
180    const below = await next(e)
181    if (e.props.hasSurvey) return below
182
183    const { Box, Button, Text } = $.ui.resolve(e)
184    const list = await read($, topics)
185    const first = await read($, seed)
186    const minimized = await read($, isMinimized)
187    const color = colorFor(await $.session.id())
188
189    const hasTopics = list.length > 0
190    const current = list[list.length - 1] ?? first ?? 'new session'
191    const earlier = list.slice(0, -1).reverse().join(' · ')
192
193    // The toggle, the dot and their spaces take four cells.
194    const room = e.props.bodyColumns - 4
195    const head = clip(current, minimized ? Math.min(MINI_WIDTH, room) : room)
196    const tail = minimized || earlier.length === 0 ? '' : clip(` · ${earlier}`, room - head.length)
197
198    const row = (
199      <Box>
200        <Button
201          key="topics-toggle"
202          plain
203          dimColor
204          label={minimized ? '▸' : '▾'}
205          onPress={() => update($, isMinimized, v => !v)}
206        />
207        <Text color={color}> ● </Text>
208        <Text color={color} bold={hasTopics} dimColor={!hasTopics}>
209          {head}
210        </Text>
211        {tail.length > 0 && <Text dimColor>{tail}</Text>}
212      </Box>
213    )
214
215    return below.type === 'engine' ? row : (
216      <Box flexDirection="column">
217        {row}
218        {below}
219      </Box>
220    )
221  })
222}
223

1export type Saved = { topics: string[]; at: number }
2
3declare module 'claude-code' {
4  interface PluginState {
5    'session-topics': { topics: string[]; seed: string | null; isMinimized: boolean }
6  }
7}
8