effort-router

1import { atom, read, update } from 'claude-code'
2import type { Register } from 'claude-code'
3
4import type { Effort } from '../types'
5import { classify } from './classify'
6
7const pinned = atom({ plugin: 'effort-router', key: 'pinned' } as const, null)
8const current = atom({ plugin: 'effort-router', key: 'current' } as const, null)
9
10const EFFORTS: readonly Effort[] = ['low', 'medium', 'high']
11const isEffort = (word: string): word is Effort =>
12  (EFFORTS as readonly string[]).includes(word)
13
14// The status line script reads the turn's choice from here, by session id.
15const CHOICE_DIR = '/tmp/claude-effort-router'
16
17export const register: Register = on => {
18  on('session.start', async ($, e, next) => {
19    await $.command.register({
20      name: 'route',
21      description: 'Pin reasoning effort (low, medium, high), or "auto" to route by prompt',
22    })
23
24    return next(e)
25  })
26
27  on('command.run', { command: 'route' }, async ($, e) => {
28    const word = e.args.trim().toLowerCase()
29
30    if (word === '') {
31      const pin = await read($, pinned)
32      return { text: pin ? `Effort pinned at ${pin}.` : 'Effort routed by prompt.' }
33    }
34    if (word === 'auto') {
35      await update($, pinned, () => null)
36      return { text: 'Effort routed by prompt again.' }
37    }
38    if (isEffort(word)) {
39      await update($, pinned, () => word)
40      return { text: `Effort pinned at ${word} until /route auto.` }
41    }
42
43    return { text: `Unknown "${word}". Use low, medium, high or auto.` }
44  })
45
46  // Decide once per prompt, so every step of the turn runs at the same effort.
47  on('prompt.submit', async ($, e, next) => {
48    if (e.command || e.isMeta) {
49      return next(e)
50    }
51
52    const pin = await read($, pinned)
53    const choice = pin ? { effort: pin, reason: 'pinned' } : classify(e.text)
54    await update($, current, () => choice)
55    await $.fs.write(`${CHOICE_DIR}/${await $.session.id()}`, choice.effort)
56
57    return next(e)
58  }).catch(($, e, next) => next(e))
59
60  // Main loop only: a subagent keeps the effort its definition asks for, and a
61  // model that takes no effort (e.effort absent) is left alone.
62  on('turn.step', async function* ($, e, next) {
63    const choice = e.agentId === undefined && e.effort !== undefined
64      ? await read($, current)
65      : null
66
67    return yield* next(choice ? { ...e, effort: choice.effort } : e)
68  })
69}
70

1import type { Choice } from '../types'
2
3const HEAVY =
4  /\b(refactor|migrat|implement|build|design|architect|debug|diagnos|investigat|fix|rewrite|review|optimi[sz]|plan)\w*/i
5const QUESTION =
6  /^(what|where|who|when|why|how|is|are|does|do|can|explain|show|list|look at)\b/i
7const LONG = 800
8const SHORT = 200
9
10// Words over cleverness: a wrong guess costs one turn, and /route overrides it.
11export const classify = (text: string): Choice => {
12  const prompt = text.trim()
13  const heavy = HEAVY.exec(prompt)
14
15  if (heavy) {
16    return { effort: 'high', reason: `"${heavy[0].toLowerCase()}"` }
17  }
18  if (prompt.length > LONG) {
19    return { effort: 'high', reason: 'long prompt' }
20  }
21  if (prompt.length < SHORT && (prompt.endsWith('?') || QUESTION.test(prompt))) {
22    return { effort: 'low', reason: 'question' }
23  }
24
25  return { effort: 'medium', reason: 'default' }
26}
27

1export type Effort = 'low' | 'medium' | 'high'
2
3export type Choice = { effort: Effort; reason: string }
4
5declare module 'claude-code' {
6  interface PluginState {
7    'effort-router': { pinned: Effort | null; current: Choice | null }
8  }
9}
10