prompt-snippets

1import { atom, read, update } from 'claude-code'
2import type { EngineInterface, PromptFillResult, PromptOrigin, Register } from 'claude-code'
3
4const NAME = /^[a-z0-9-]{1,32}$/
5const VERBS = new Set(['save', 'list', 'rm', 'help'])
6const PREVIEW = 60
7// Where a prompt the person wrote arrives from: the terminal, the desktop app or another SDK host, Remote Control.
8const BY_PERSON = new Set<PromptOrigin['kind']>(['composer', 'sdk', 'bridge'])
9// User-role rows the person did not type: a command's record and output, reminders and
10// notices, the summary /compact leaves, messages from teammates and channels.
11const NOT_TYPED =
12  /^(<(command-|local-command-|system-reminder|bash-|task-notification|teammate-message|channel)|\[Request interrupted|This session is being continued from a previous conversation)/
13
14const typed = atom({ plugin: 'prompt-snippets', key: 'typed' } as const, null)
15
16const USAGE = [
17  '- `/snip save <name>` saves your last prompt',
18  '- `/snip <name>` inserts a snippet into the prompt',
19  '- `/snip list` shows your snippets',
20  '- `/snip rm <name>` removes one',
21].join('\n')
22
23// The answer is drawn as Markdown: keep its punctuation from acting.
24const escape = (text: string) => text.replace(/[\\`*_~<>[\]|&]/g, '\\$&')
25
26const missing = (name: string) => `No snippet named ${name}. \`/snip list\` shows yours.`
27const badName = (name: string) =>
28  `${escape(name)} is not a snippet name: use 1-32 characters of \`a-z\`, \`0-9\` and \`-\`.`
29const failed = (command: string) => (error: unknown) =>
30  `\`${command}\` did not finish: ${error instanceof Error ? error.message : String(error)}`
31
32// A fence longer than any backtick run in the text, so the text shows as it is.
33function fence(text: string): string {
34  const runs = text.match(/`+/g) ?? []
35  const bar = '`'.repeat(Math.max(3, ...runs.map(run => run.length + 1)))
36
37  return `${bar}\n${text.trimEnd()}\n${bar}`
38}
39
40// Puts text in at the cursor and answers `done`, or why it could not.
41async function insert($: EngineInterface, text: string, done: string): Promise<string> {
42  // Only the terminal's prompt box takes a mod's text: the desktop app draws its own, -p has none.
43  const hasBox = (await $.session.surfaces()).includes('terminal')
44  const filled: PromptFillResult = hasBox
45    ? await $.prompt.fill({ text, mode: 'insert' })
46    : { isFilled: false, refusal: 'no_composer' }
47
48  if (filled.isFilled) return done
49  if (filled.refusal === 'no_composer') {
50    return `This session has no prompt box a mod can fill (the desktop app, \`claude -p\`). Copy it from here:\n\n${fence(text)}`
51  }
52  if (filled.refusal === 'dialog') return 'A dialog holds the keys. Close it, then run the command again.'
53
54  return 'Another plugin kept the text out of the prompt box.'
55}
56
57async function lastPrompt($: EngineInterface): Promise<string | undefined> {
58  const sent = await read($, typed)
59  if (sent !== null) return sent
60
61  // Nothing sent since the mod loaded (a resumed session): the transcript's last row that reads as typed.
62  const rows = await $.session.messages()
63
64  return rows.findLast(
65    row =>
66      row.role === 'user' &&
67      !row.toolResults?.length &&
68      row.text.trim() !== '' &&
69      !NOT_TYPED.test(row.text.trimStart()),
70  )?.text
71}
72
73function preview(text: string): string {
74  const flat = text.replace(/\s+/g, ' ').trim()
75
76  return escape(flat.length > PREVIEW ? `${flat.slice(0, PREVIEW).trimEnd()}…` : flat)
77}
78
79async function table($: EngineInterface): Promise<string> {
80  const names = (await $.store.keys()).sort()
81  if (names.length === 0) {
82    return 'No snippets yet. Send a prompt, then `/snip save <name>` keeps it.'
83  }
84  const rows = await Promise.all(
85    names.map(async name => `| ${name} | ${preview(String(await $.store.get(name)))} |`),
86  )
87
88  return ['| Name | Snippet |', '| --- | --- |', ...rows].join('\n')
89}
90
91async function snip($: EngineInterface, args: string): Promise<string> {
92  const [verb = '', name = '', ...rest] = args.trim().split(/\s+/)
93
94  if (verb === '' || verb === 'help') return USAGE
95  if (verb === 'list') return name === '' ? table($) : `\`/snip list\` takes no name.\n\n${USAGE}`
96
97  if (verb === 'save' || verb === 'rm') {
98    if (name === '') return `Name the snippet: \`/snip ${verb} <name>\`.`
99    if (!NAME.test(name) || rest.length > 0) return badName([name, ...rest].join(' '))
100    if (VERBS.has(name)) return `${name} is a \`/snip\` command, so it cannot name a snippet.`
101    const held = await $.store.get(name)
102
103    if (verb === 'rm') {
104      if (held === undefined) return missing(name)
105      await $.store.delete(name)
106      return `Removed snippet ${name}.`
107    }
108
109    const prompt = await lastPrompt($)
110    if (prompt === undefined) return 'No prompt to save yet. Send one, then `/snip save <name>`.'
111    try {
112      await $.store.set(name, prompt)
113    } catch {
114      return 'The snippet store refused it: all snippets together hold at most 4 MiB. `/snip rm <name>` frees room.'
115    }
116    return `${held === undefined ? 'Saved' : 'Replaced'} snippet ${name} with your last prompt. \`/snip ${name}\` inserts it.`
117  }
118
119  if (!NAME.test(verb) || name !== '') return `${badName(args.trim())}\n\n${USAGE}`
120  const text = await $.store.get(verb)
121  if (typeof text !== 'string') return missing(verb)
122
123  return insert($, text, `Inserted snippet ${verb}.`)
124}
125
126async function quote($: EngineInterface, isFullscreen: boolean): Promise<string> {
127  const lines = (await $.ui.selection())?.text.replace(/\s+$/, '')
128  if (!lines) {
129    // The main-screen terminal never shows a mod its selection.
130    return isFullscreen
131      ? 'Nothing is selected. Select text with the mouse, then `/quote`.'
132      : "Nothing is selected that `/quote` can read: it reads the mouse selection in the desktop app and in the terminal's fullscreen layout."
133  }
134  const quoted = `${lines
135    .split(/\r?\n/)
136    .map(line => `> ${line}`)
137    .join('\n')}\n\n`
138
139  return insert($, quoted, 'Quoted the selection into the prompt.')
140}
141
142export const register: Register = on => {
143  on('session.start', async ($, e, next) => {
144    await $.command.register({
145      name: 'snip',
146      description: 'Save, list and insert reusable prompt snippets',
147      argumentHint: '<name> | save <name> | list | rm <name>',
148      immediate: true,
149    })
150    await $.command.register({
151      name: 'quote',
152      description: 'Quote your mouse selection into the prompt',
153      immediate: true,
154    })
155
156    return next(e)
157  })
158
159  // Only notes the prompt down: a failure lets it through.
160  on('prompt.submit', async ($, e, next) => {
161    if (BY_PERSON.has(e.origin.kind) && !e.isMeta && !e.command && e.text.trim() !== '') {
162      await update($, typed, () => e.text)
163    }
164
165    return next(e)
166  }).catch(($, e, next) => next(e))
167
168  on('command.run', { command: 'snip' }, async ($, e) => ({
169    text: await snip($, e.args).catch(failed('/snip')),
170  }))
171
172  on('command.run', { command: 'quote' }, async ($, e) => ({
173    text: await quote($, e.presentation.isFullscreen).catch(failed('/quote')),
174  }))
175
176  // The list is a Markdown table: draw it as one rather than as the row's plain text.
177  on('ui.render', { component: 'CommandOutput', props: { command: 'snip' } }, ($, e, next) => {
178    if (e.props.isErrored || e.props.args.trim() !== 'list') return next(e)
179    const { Markdown } = $.ui.resolve(e)
180
181    return <Markdown text={e.props.text} />
182  })
183}
184

1// The last prompt the person sent this session; null until they send one.
2export type LastPrompt = string | null
3
4declare module 'claude-code' {
5  interface PluginState {
6    'prompt-snippets': { typed: LastPrompt }
7  }
8}
9