src/inject.browser.js

/* beacon inject — runs in any browser page
   Auto-injected via CDP on every page, or load manually:
     bookmarklet: javascript:(function(){var s=document.createElement('script');s.src='__BEACON_BASE__/inject.js';document.head.appendChild(s)})()
     console:     await fetch('__BEACON_BASE__/inject.js').then(r=>r.text()).then(eval)
*/
;(function () {
  if (window.__beacon) return  // already injected

  const BASE = '__BEACON_BASE__'

  const _log  = (msg, style = 'color:#7df;font-family:monospace;font-size:13px') =>
    console.log('%c' + msg, style)

  const _err  = (msg) =>
    console.error('%c[beacon] ' + msg, 'color:#f77;font-family:monospace')

  const _post = (path, body) =>
    fetch(BASE + path, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(body),
    }).then(r => r.json())

  const _get = (path) => fetch(BASE + path).then(r => r.text())

  // ── Core beacon interface ─────────────────────────────────────────────────

  window.__beacon = {
    base: BASE,

    agent: async (url) => {
      try {
        const text = await _get(`/raw?url=${encodeURIComponent(url)}`)
        _log(text)
        return text
      } catch (e) { _err(e.message) }
    },

    here: async () => window.__beacon.agent(location.href),

    ask: async (question) => {
      try {
        _log(`[beacon] thinking...`, 'color:#aaa;font-style:italic')
        const { reply, error } = await _post('/chat', {
          message: question,
          context: location.href,
        })
        if (error) { _err(error); return }
        _log(reply, 'color:#afc;font-family:monospace;font-size:13px;line-height:1.5')
        return reply
      } catch (e) { _err(e.message) }
    },

    feed: async (url) => {
      try {
        const xml = await _get(`/feed?url=${encodeURIComponent(url || location.href)}`)
        _log(xml)
        return xml
      } catch (e) { _err(e.message) }
    },

    json: async (url) => {
      try {
        const r = await fetch(`${BASE}/json?url=${encodeURIComponent(url || location.href)}`)
        const data = await r.json()
        console.table(data)
        return data
      } catch (e) { _err(e.message) }
    },

    save: async (name) => {
      const n = name || location.hostname.replace(/\./g, '_')
      const { saved } = await _post(`/session/${n}`, {})
      _log(`[beacon] session saved → ${saved}`)
    },
  }

  // Flat console shortcuts
  ;['agent','here','ask','feed','json','save'].forEach(k => { window[k] = window.__beacon[k] })

  // ── Chrome DevTools third-party tool registration ─────────────────────────
  // Exposes beacon as callable tools to Chrome DevTools MCP agents
  // (mcp__chrome-devtools__execute_developer_tool / list_developer_tools)

  const BEACON_TOOLS = [
    {
      name: 'beacon_fetch',
      description: 'Fetch clean readable text from any URL through the owner\'s authenticated browser session.',
      schema: {
        type: 'object',
        properties: { url: { type: 'string', description: 'URL to fetch' } },
        required: ['url'],
      },
      execute: async ({ url }) => window.__beacon.agent(url),
    },
    {
      name: 'beacon_ask',
      description: 'Ask the beacon LLM a question with the current page as context.',
      schema: {
        type: 'object',
        properties: { question: { type: 'string', description: 'What to ask about this page' } },
        required: ['question'],
      },
      execute: async ({ question }) => window.__beacon.ask(question),
    },
    {
      name: 'beacon_feed',
      description: 'Generate an RSS feed from any URL or the current page.',
      schema: {
        type: 'object',
        properties: { url: { type: 'string', description: 'URL (omit for current page)' } },
      },
      execute: async ({ url } = {}) => window.__beacon.feed(url),
    },
    {
      name: 'beacon_json',
      description: 'Return structured article JSON (title, author, content) from any URL.',
      schema: {
        type: 'object',
        properties: { url: { type: 'string', description: 'URL (omit for current page)' } },
      },
      execute: async ({ url } = {}) => window.__beacon.json(url),
    },
    {
      name: 'beacon_save_session',
      description: 'Save the current authenticated session for this domain so the beacon can replay it.',
      schema: { type: 'object', properties: { name: { type: 'string' } } },
      execute: async ({ name } = {}) => window.__beacon.save(name),
    },
  ]

  // Chrome DevTools MCP third-party tool protocol
  // The DevTools MCP agent calls window.__chrome_devtools_tools__() to discover tools
  window.__chrome_devtools_tools__ = () => BEACON_TOOLS.map(t => ({
    name: t.name,
    description: t.description,
    inputSchema: t.schema,
  }))

  // Execution handler — DevTools MCP calls this to invoke a tool
  window.__chrome_devtools_execute_tool__ = async (name, args) => {
    const tool = BEACON_TOOLS.find(t => t.name === name)
    if (!tool) return { error: `unknown tool: ${name}` }
    try {
      const result = await tool.execute(args || {})
      return { result }
    } catch (e) {
      return { error: e.message }
    }
  }

  // ── WebMCP registration (experimental — Chrome 149+ with flags) ───────────
  // Flags: chrome://flags/#devtools-webmcp-support + #enable-webmcp-testing
  // When stable, exposes beacon tools to Chrome's built-in AI panel (Gemini etc.)
  // and any WebMCP-compatible agent — LLM-agnostic, your session, any backend.

  function registerWebMCP() {
    if (!window.navigator?.registerMCPTool) return  // flag not enabled

    for (const tool of BEACON_TOOLS) {
      navigator.registerMCPTool({
        name: tool.name,
        description: tool.description,
        inputSchema: tool.schema,
        execute: tool.execute,
      })
    }
    _log('[beacon] WebMCP tools registered — visible to Chrome AI panel', 'color:#fa0;font-size:11px')
  }

  // Retry registration once DOM is ready (API may initialise late)
  if (document.readyState === 'loading') {
    document.addEventListener('DOMContentLoaded', registerWebMCP)
  } else {
    registerWebMCP()
  }

  // ── Banner ────────────────────────────────────────────────────────────────

  console.log(
    '%c  📡 beacon  %c active\n' +
    '%c  ask("summarize this")   here()   feed()   json()   save()\n' +
    '%c  DevTools MCP: __chrome_devtools_tools__()   WebMCP: auto',
    'background:#1a1a2e;color:#7df;font-weight:bold;padding:3px 8px;border-radius:3px 0 0 3px',
    'background:#0f3460;color:#eee;padding:3px 8px;border-radius:0 3px 3px 0',
    'color:#888;font-family:monospace;font-size:11px',
    'color:#555;font-family:monospace;font-size:10px'
  )
})()