amp-review — a deterministic Amp review skill + invoker plugin

A developer created amp-review, a deterministic skill review and invoker plugin for the Amp code editor. The plugin loads skills from multiple directories, parses SKILL.md files, and allows users to invoke skills via $skillname tokens in messages. It provides a deterministic way to manage and invoke skills within the Amp environment.

| import type { | | AgentStartEvent, | | CommandSubscription, | | PluginAPI, | | PluginCommandContext, | | PluginEventContext, | | StatusItem, | | } from '@ampcode/plugin'; | | import { existsSync, readdirSync, readFileSync, statSync } from 'node:fs'; | | import { basename, join } from 'node:path'; | | | | type Skill = { | | name: string; | | description: string; | | path: string; | | body: string; | | }; | | | | const SKILL DIRS = | | '~/.agents/skills', | | '~/.config/amp/skills', | | '~/.config/agents/skills', | | '~/.codex/skills', | | '~/.claude/skills', | | '.agents/skills', | | '.claude/skills', | | ; | | | | const SKILL TOKEN = / ?:^|\s \$ a-zA-Z0-9 a-zA-Z0-9 - ?=\s|$ /g; | | | | const pendingSkillsByThread = new Map<string, string ; | | | | function homePath path: string : string { | | if path === '~' { | | return process.env.HOME || path; | | } | | if path.startsWith '~/' { | | const home = process.env.HOME; | | return home ? join home, path.slice 2 : path; | | } | | return path; | | } | | | | function frontmatterValue frontmatter: string, key: string : string | undefined { | | const value = frontmatter.match new RegExp ^${key}:\\s .+ $ , 'm' ?. 1 ?.trim ; | | return value?.replace /^ "' | "' $/g, '' ; | | } | | | | function unique<T values: T : T { | | return ...new Set values ; | | } | | | | function parseSkillFile path: string, fallbackName: string : Skill | null { | | const content = readFileSync path, 'utf8' ; | | const frontmatterMatch = content.match /^---\r?\n \s\S ? \r?\n---\r?\n? \s\S $/ ; | | const frontmatter = frontmatterMatch?. 1 ?? ''; | | const body = frontmatterMatch?. 2 ?? content .trim ; | | const name = frontmatterValue frontmatter, 'name' ?? fallbackName; | | const description = frontmatterValue frontmatter, 'description' ?? firstMeaningfulLine body ; | | | | if name { | | return null; | | } | | | | return { name, description, path, body }; | | } | | | | function firstMeaningfulLine content: string : string { | | return | | content | | .split '\n' | | .map line = line.trim .replace /^ +\s /, '' | | .find line = line.length 0 ?? 'Invoke this skill.' | | ; | | } | | | | function loadSkills : Skill { | | const skills = new Map<string, Skill ; | | | | for const configuredDir of SKILL DIRS { | | const dir = homePath configuredDir ; | | if existsSync dir { | | continue; | | } | | | | for const entry of readdirSync dir { | | const skillDir = join dir, entry ; | | const skillFile = join skillDir, 'SKILL.md' ; | | if existsSync skillFile || statSync skillFile .isFile { | | continue; | | } | | | | const skill = parseSkillFile skillFile, basename skillDir ; | | if skill && skills.has skill.name { | | skills.set skill.name, skill ; | | } | | } | | } | | | | return ...skills.values .sort a, b = a.name.localeCompare b.name ; | | } | | | | function selectedSkillNames skillsByName: Map<string, Skill , message: string, pending: string : string { | | const names = ...pending ; | | | | for const match of message.matchAll SKILL TOKEN { | | const name = match 1 ; | | if skillsByName.has name { | | names.push name ; | | } | | } | | | | return unique names ; | | } | | | | function buildSkillInvocationRequest skills: Skill : string { | | return | | The user explicitly invoked ${skills.length === 1 ? 'this skill' : 'these skills'} for this turn: ${skills.map skill = skill.name .join ', ' }. , | | "Use Amp's native skill invocation mechanism for the named skill s before working on the user request. Do not treat this as ordinary prose; load/invoke the skill s so the invocation appears in the agent actions when the runtime supports it.", | | ...skills.map skill = ${skill.name}: ${skill.description} , | | .join '\n\n' ; | | } | | | | function statusText names: string : string { | | if names.length === 0 { | | return ''; | | } | | return - Skills: ${names.map name = $${name} .join ' ' } ; | | } | | | | async function chooseSkill ctx: PluginCommandContext, skills: Skill : Promise<string | undefined { | | const options = skills.map skill, index = ${index + 1}. ${skill.name} — ${skill.description} ; | | const selected = await ctx.ui.select { | | title: 'Select skill for next message', | | message: 'The selected skill is injected into the next user message in the active thread.', | | options, | | } ; | | const selectedIndex = selected ? options.indexOf selected : -1; | | | | return selectedIndex = 0 ? skills selectedIndex ?.name : undefined; | | } | | | | export default function amp: PluginAPI { | | let skills = loadSkills ; | | let skillsByName = new Map skills.map skill = skill.name, skill ; | | let pendingSkillsForNextThread: string = ; | | let cancelCommand: CommandSubscription | undefined; | | let showPendingCommand: CommandSubscription | undefined; | | let skillCommands: CommandSubscription = ; | | let statusItem: StatusItem | undefined; | | | | function refreshSkills { | | skills = loadSkills ; | | skillsByName = new Map skills.map skill = skill.name, skill ; | | registerSkillCommands ; | | } | | | | function addPendingSkill threadID: string | undefined, skillName: string : string { | | if threadID { | | pendingSkillsForNextThread = unique ...pendingSkillsForNextThread, skillName ; | | updatePendingCommandAvailability ; | | updatePendingStatus ; | | return pendingSkillsForNextThread; | | } | | | | const pending = pendingSkillsByThread.get threadID ?? ; | | const nextPending = unique ...pending, skillName ; | | pendingSkillsByThread.set threadID, nextPending ; | | updatePendingCommandAvailability ; | | updatePendingStatus ; | | return nextPending; | | } | | | | function activeThreadID ctx: PluginCommandContext : string | undefined { | | return ctx.thread?.id ?? amp.activeThread.current?.id; | | } | | | | function pendingSkills ctx?: PluginCommandContext : string { | | const threadID = ctx ? activeThreadID ctx : amp.activeThread.current?.id; | | return unique | | ...pendingSkillsForNextThread, | | ... threadID ? pendingSkillsByThread.get threadID ?? : , | | ; | | } | | | | function updatePendingCommandAvailability { | | const hasPending = pendingSkills .length 0; | | const availability = hasPending | | ? { type: 'enabled' as const } | | : { type: 'disabled' as const, reason: 'No pending skills' }; | | cancelCommand?.setAvailability availability ; | | showPendingCommand?.setAvailability availability ; | | } | | | | function updatePendingStatus { | | if amp.experimental { | | return; | | } | | | | const pending = pendingSkills ; | | if pending.length === 0 { | | statusItem?.unsubscribe ; | | statusItem = undefined; | | return; | | } | | | | if statusItem && pending.length 0 { | | statusItem = amp.experimental.createStatusItem ; | | } | | | | statusItem?.update { | | text: statusText pending , | | url: 'command:skill-invoker.show-pending', | | } ; | | } | | | | function registerSkillCommands { | | for const command of skillCommands { | | command.unsubscribe ; | | } | | skillCommands = ; | | | | for const skill of skills { | | skillCommands.push | | amp.registerCommand | | skill-invoker.invoke.${skill.name} , | | { | | title: skill.name, | | category: 'Skill', | | description: skill.description, | | }, | | async ctx = { | | const threadID = activeThreadID ctx ; | | const pending = addPendingSkill threadID, skill.name ; | | await ctx.ui.notify | | ${statusText pending } selected for next message. Run “Skill: Cancel pending skills” to cancel. , | | ; | | }, | | , | | ; | | } | | } | | | | amp.activeThread.subscribe = updatePendingStatus ; | | | | amp.registerCommand | | 'skill-invoker.select', | | { | | title: 'Select skill…', | | category: 'Skill', | | description: 'Choose a skill to invoke with the next message.', | | }, | | async ctx = { | | refreshSkills ; | | const threadID = activeThreadID ctx ; | | if skills.length === 0 { | | await ctx.ui.notify | | 'No skills found in ~/.config/agents/skills, ~/.codex/skills, or ~/.claude/skills.', | | ; | | return; | | } | | | | const skillName = await chooseSkill ctx, skills ; | | if skillName { | | return; | | } | | | | const pending = addPendingSkill threadID, skillName ; | | await ctx.ui.notify | | ${statusText pending } selected for next message. Run “Skill: Cancel pending skills” to cancel. , | | ; | | }, | | ; | | | | cancelCommand = amp.registerCommand | | 'skill-invoker.cancel', | | { | | title: 'Cancel pending skills', | | category: 'Skill', | | description: 'Clear skills selected from the command palette before sending.', | | availability: { type: 'disabled', reason: 'No pending skills' }, | | }, | | async ctx = { | | const threadID = activeThreadID ctx ; | | if threadID { | | pendingSkillsByThread.delete threadID ; | | } | | pendingSkillsForNextThread = ; | | updatePendingCommandAvailability ; | | updatePendingStatus ; | | await ctx.ui.notify 'Pending skills cleared.' ; | | }, | | ; | | | | showPendingCommand = amp.registerCommand | | 'skill-invoker.show-pending', | | { | | title: 'Show pending skills', | | category: 'Skill', | | description: 'Show skills selected for the next message.', | | availability: { type: 'disabled', reason: 'No pending skills' }, | | }, | | async ctx = { | | await ctx.ui.notify ${statusText pendingSkills ctx } selected for next message. ; | | }, | | ; | | | | amp.registerCommand | | 'skill-invoker.reload', | | { | | title: 'Reload skill list', | | category: 'Skill', | | description: 'Rescan local skill directories.', | | }, | | async ctx = { | | refreshSkills ; | | await ctx.ui.notify Loaded ${skills.length} skills. ; | | }, | | ; | | | | registerSkillCommands ; | | | | amp.on 'agent.start', async event: AgentStartEvent, ctx: PluginEventContext<'agent.start' = { | | const pending = unique | | ...pendingSkillsForNextThread, | | ... pendingSkillsByThread.get event.thread.id ?? , | | ; | | const names = selectedSkillNames skillsByName, event.message, pending ; | | pendingSkillsForNextThread = ; | | pendingSkillsByThread.delete event.thread.id ; | | updatePendingCommandAvailability ; | | updatePendingStatus ; | | | | if names.length === 0 { | | return {}; | | } | | | | const invokedSkills = names | | .map name = skillsByName.get name | | .filter skill : skill is Skill = Boolean skill ; | | | | return { | | message: { | | content: buildSkillInvocationRequest invokedSkills , | | display: false, | | }, | | }; | | } ; | | | | amp.logger.log skill-invoker loaded ${skills.length} skills. ; | | } |