Cebian · Open-Source AI Side Panel Agent

Tracking since May 20, 2026.

Changelog

• Jun 8, 2026
  description

  Cebian is an AI assistant that lives permanently in your browser's side panel.
  Instead of switching tabs, copying text, pasting into a chat app, and switching back,
  you simply open the panel and talk to the AI right beside the page you are reading.
  
  No account. No subscription. No data sent anywhere except to the AI provider you choose.
  
  ────────────────────────────────────────
  WHY INSTALL CEBIAN?
  ────────────────────────────────────────
  
  Most AI chat tools require you to leave the page you are working on.
  You copy something, switch to a chat tab, paste, wait, copy the result,
  switch back, and paste again. Cebian removes all of that switching.
  
  The assistant panel sits next to your browser content at all times.
  You can highlight a paragraph, click "Pick element," and the AI immediately
  has that exact text as context — no copy-pasting required.
  
  Additionally, every mainstream AI assistant requires you to create an account
  with their service and agree to their data practices. Cebian is different:
  you bring your own API key from whichever provider you already trust,
  and your conversation history is stored only in your own browser.
  The developer has no server, no database, and no access to your data.
  
  ────────────────────────────────────────
  WHO IS CEBIAN FOR?
  ────────────────────────────────────────
  
  Developers
    — Ask the AI about a GitHub issue, a Stack Overflow answer, or a documentation
      page while you are looking at it. Attach a screenshot of a UI bug directly.
      Use the built-in mobile-emulation toggle to test responsive layouts without
      opening DevTools manually.
  
  Writers and researchers
    — Summarize, translate, or rewrite any article without leaving the page.
      Use the {{selected_text}} prompt variable to instantly send highlighted
      passages to a custom rewrite or translation template.
  
  Power users who work with multiple AI providers
    — Some tasks suit GPT-4o; others suit Claude; others suit a local Ollama model.
      Cebian lets you switch providers mid-session without re-entering context.
      Connect any OpenAI-compatible endpoint as a custom provider.
  
  Privacy-conscious users
    — Nothing is stored on a third-party server. Chat history, prompts, API keys,
      and attachments all live in your browser's local storage.
      If you uninstall the extension, everything is gone — by design.
  
  Teams and individuals who do repetitive AI tasks
    — The Slash Prompts feature lets you build a personal library of prompt templates
      with fill-in variables. For example, a "Summarize this page" template can be
      triggered with /sum and immediately send the current page content to the AI.
      No retyping the same instructions every session.
  
  ────────────────────────────────────────
  WHAT CAN YOU DO WITH CEBIAN?
  ────────────────────────────────────────
  
  Read and discuss any web page
    Open the side panel on any article, documentation page, or search result.
    Ask the AI to summarize, explain, translate, or critique what is on screen.
    The AI can read the page title, URL, and full page text as context.
  
  Pick any element on the page
    Click the element-picker tool, then click any DOM element on the page —
    a table, a code block, an error message — and it is attached to your message.
    The AI sees exactly what you clicked, not a vague description.
  
  Reuse prompts across sessions
    Create prompt templates once. Use slash commands (/) to trigger them instantly.
    Templates support variables:
      {{selected_text}}   — text currently highlighted on the page
      {{page_url}}        — the current tab's URL
      {{page_title}}      — the current tab's title
      {{clipboard}}       — whatever is currently in your clipboard
      {{date}}            — today's date
  
  Extend the AI with Skills
    Skills are packages of instructions that teach the AI how to handle
    specific tasks — for example, a skill that knows how to format a pull-request
    description, or one that knows your company's internal naming conventions.
    Skills are stored locally and can be imported or exported as files.
  
  Connect external tools via MCP
    Cebian includes a built-in Model Context Protocol (MCP) client.
    If you run a local MCP server (for example, a tool that queries your database
    or reads files from your filesystem), you can connect it to Cebian and the AI
    will be able to call those tools directly from the chat.
  
  Emulate a mobile device
    A single click in the toolbar toggles mobile-device emulation on the active tab.
    This uses the same Chrome DevTools Protocol mechanism as the built-in DevTools —
    no extra setup required.
  
  Attach files and screenshots
    Drag-and-drop images, paste screenshots, or upload text files as attachments
    to any message. Useful for asking the AI about a design mockup, a log file,
    or an error dialog you cannot otherwise select as text.
  
  ────────────────────────────────────────
  SUPPORTED AI PROVIDERS
  ────────────────────────────────────────
  
    • OpenAI (GPT-4o, o1, o3, and others)
    • Anthropic (Claude 3.x and later)
    • Google (Gemini models)
    • GitHub Copilot (via OAuth — uses your existing Copilot subscription)
    • OpenAI Codex CLI (via OAuth)
    • Any OpenAI-compatible endpoint (Ollama, LM Studio, Azure OpenAI, etc.)
  
  You supply the API key. Cebian stores it in your browser's local storage.
  It is never sent anywhere except directly to the provider's API endpoint.
  
  ────────────────────────────────────────
  PRIVACY AND DATA HANDLING
  ────────────────────────────────────────
  
  Cebian has no backend server of its own.
  
  The following data stays entirely on your device:
    — Chat history and session context
    — API keys and provider configuration
    — Prompt templates and Skills
    — Attached files and screenshots
    — Custom MCP server addresses
  
  The only data that leaves your device is the content of each message you send,
  which is transmitted directly to the AI provider API you configured.
  That transmission is governed by the privacy policy of the provider you chose
  (OpenAI, Anthropic, Google, etc.), not by Cebian.
  
  Full source code: https://github.com/maotoumao/Cebian
  License: GNU Affero General Public License v3.0 (AGPL-3.0)
  
  ────────────────────────────────────────
  PERMISSIONS — WHY EACH ONE IS NEEDED
  ────────────────────────────────────────
  
  sidePanel
    Displays the assistant in the browser's built-in side panel.
  
  activeTab, tabs, scripting
    Reads the content (URL, title, text, DOM elements) of the tab you are
    currently viewing, when you explicitly request it in a message.
    Also required for the element-picker overlay.
  
  storage
    Saves your settings, chat history, prompt templates, and API keys
    locally in your browser. Nothing is synced externally.
  
  alarms
    Keeps MCP server connections alive in the background with periodic pings.
  
  webNavigation
    Detects when you navigate to a new page so the side panel can refresh
    the current-page context automatically.
  
  bookmarks, history, cookies, topSites, sessions
    These are exposed as optional agent tools. They are never accessed
    automatically. The AI only calls them if you explicitly ask it to —
    for example, "search my history for that article I read last week."
  
  downloads, notifications
    Allow the AI to trigger a file download or show a browser notification
    when you ask it to perform a task that produces those results.
  
  clipboardRead
    Reads your clipboard only when you use the {{clipboard}} variable
    in a prompt template. Never accessed automatically.
  
  debugger
    Required for mobile-device emulation. Cebian uses the Chrome DevTools
    Protocol (CDP) to toggle device emulation on the active tab — the same
    mechanism used by Chrome's built-in DevTools. No debugging data is
    recorded or transmitted.
  
  Access to all sites (<all_urls>)
    Required to inject the element-picker UI and the page-content reader
    into whichever tab you are viewing. Without this permission, the
    element-picker and page-reading features would not work on most sites.
    No content is collected from sites you do not explicitly interact with.
  
  ────────────────────────────────────────
  GETTING STARTED
  ────────────────────────────────────────
  
  1. Install the extension.
  2. Click the Cebian icon in the Chrome toolbar to open the side panel.
  3. Open Settings → Providers, choose your AI provider, and enter your API key.
  4. Select a model from the dropdown in the chat header.
  5. Start a conversation.
  
  Source code and documentation: https://github.com/maotoumao/Cebian
  Bug reports and feature requests: https://github.com/maotoumao/Cebian/issues

  Cebian is an open-source AI agent that lives in your browser's side panel.
  Bring your own API key from OpenAI, Anthropic, Google, or any OpenAI-compatible
  provider — no account, no subscription, no middleman. Your chats, prompts, and
  files stay in your browser; only the messages you actually send leave, and they
  go straight to the provider you picked.
  
  It's a real agent, not a chat box: it can read the page you're on, pick any
  element off the screen as context, call external tools through MCP, run reusable
  Skills, attach screenshots and files, and switch between models mid-conversation
  without losing context.
  
  ────────────────────────────────────────
  KEY FEATURES
  ────────────────────────────────────────
  
  • Page-aware chat — Ask about the article, docs page, or search result you're
    looking at. The AI sees the page title, URL, and full text as context.
  
  • Element picker — Click any element on the page (a table, a code block, an
    error message) to attach it precisely to your next message.
  
  • Slash prompts — Build a personal library of prompt templates with variables
    like {{selected_text}}, {{page_url}}, {{clipboard}}. Trigger with /sum,
    /translate, and so on.
  
  • Skills — Package multi-step workflows or domain knowledge into reusable
    Skills the agent invokes on demand. Local files, importable and exportable.
  
  • MCP tools — Built-in Model Context Protocol client. Plug in a local MCP
    server (database, filesystem, internal API) and the agent can call it from
    chat.
  
  • Mobile-device emulation — Toggle responsive-design emulation on the active
    tab with one click. Uses Chrome DevTools Protocol, no separate setup.
  
  • Multi-model — Works with OpenAI, Anthropic, Google Gemini, GitHub Copilot
    (via OAuth), and any OpenAI-compatible endpoint. Switch providers or models
    mid-session without losing context.
  
  • Attach anything — Drag, drop, paste, or upload images and files into any
    message.
  
  ────────────────────────────────────────
  WHO IT'S FOR
  ────────────────────────────────────────
  
  • Developers — ask about a GitHub issue, a Stack Overflow answer, or a docs
    page in place; attach screenshots of UI bugs; toggle mobile emulation
    without opening DevTools.
  
  • Writers and researchers — summarize, translate, or rewrite anything you're
    reading without leaving the page.
  
  • People who already pay for multiple AI providers — pick the right model per
    task instead of being locked into one.
  
  • Privacy-conscious users — nothing leaves your machine except the messages
    you explicitly choose to send.
  
  ────────────────────────────────────────
  PRIVACY & OPEN SOURCE
  ────────────────────────────────────────
  
  Cebian has no backend. Chat history, API keys, prompt templates, Skills,
  attachments, and MCP configurations all live in your browser's local storage.
  The only outbound network traffic is the message content you send, going
  directly to the AI provider you configured under that provider's privacy
  terms.
  
  Licensed under AGPL-3.0. Full source code on GitHub. Uninstall the extension
  and every byte of your data is gone — by design.
  
  ────────────────────────────────────────
  LINKS
  ────────────────────────────────────────
  
  Source code:    https://github.com/maotoumao/Cebian
  Issues & ideas: https://github.com/maotoumao/Cebian/issues

• Jun 8, 2026
  short_description

  AI-powered browser sidebar assistant

  Side panel AI agent. BYO key (OpenAI/Anthropic/Google), no account. Element picker, MCP tools, skills. AGPL-3.0, local-first.

• Jun 8, 2026
  name

  Cebian

  Cebian · Open-Source AI Side Panel Agent

Permissions & access

Permissions

sidePanelactiveTabtabsscriptingstoragealarmsoffscreendebuggerwebNavigationbookmarkshistorycookiestopSitessessionsdownloadsnotificationsclipboardRead

Host access

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Screenshots