Best AI Sidebar Extensions (Work Inside ChatGPT, No Tab Switching)

TL;DR: The best AI sidebar extension depends on the job. For AI on every web page, Sider and Monica have the largest user bases, Merlin and MaxAI are close alternatives, and HARPA leans into automation. For writing better prompts inside ChatGPT, Claude, or Gemini without leaving the chat, a prompt sidebar like Prompt Architects fits better.

What does tab switching actually cost you?

It costs steps, and the steps add up because they repeat. We didn't run a stopwatch study, and we won't quote one we can't source. What we can do is count the steps in a task most ChatGPT users do daily: improving a rough prompt before sending it.

Without a sidebar (separate tool in another tab):

1. Select your rough prompt in ChatGPT and copy it.
2. Switch to the tab with your prompt tool or document.
3. Paste, then run the improvement or find your saved version.
4. Select the result and copy it.
5. Switch back to ChatGPT.
6. Select the old text, paste over it, and check nothing was lost.

With a prompt sidebar inside ChatGPT:

1. Open the sidebar with a hotkey or click.
2. Enhance the prompt, or pick a saved one.
3. Insert it into the chat box with one click.

That's six steps with two context switches against three with none. The saving per prompt is small. The saving across 30 prompts a day, every day, is what people actually notice. You can time it yourself with the script near the end of this page.

What kinds of AI sidebar extensions are there?

Two, and mixing them up is the most common buying mistake.

• General AI sidebars open on any web page. You chat with one or more models, summarize the article in front of you, translate, draft replies, and often generate images. Sider, Monica, Merlin, HARPA, MaxAI, and Google's Gemini in Chrome are in this group.
• Prompt sidebars open inside AI chat sites. They don't give you another chatbot; they help you write, improve, store, and reuse what you send to the chatbot you already use. Prompt Architects is in this group.

If you mostly want AI help while reading or writing on ordinary websites, you want the first kind. If you already spend your day inside ChatGPT, Claude, or Gemini and lose time re-writing prompts, you want the second.

The best AI sidebar extensions compared

1. Sider: the biggest general sidebar

Best for: people who want many models, group chat across them, and AI on every page.

Sider's Chrome Web Store listing showed 5,000,000 users, 4.9 from 114.4K ratings, and version 5.32.9, updated September 15, 2026. The listing describes a sidebar that brings ChatGPT, DeepSeek, Gemini, Claude, and Grok together for search, reading, and writing, a group chat where several models answer at once, and a prompt library you open by typing a slash. Its pricing page now groups the product into Chat, Hand (browser automation), Code, and Create.

For pricing, free-plan limits, and a direct comparison, read our Sider vs Monica breakdown and the longer Sider AI review rather than a summary here.

Weaknesses: it's a broad product, so the prompt library is one feature among dozens, not the centre of it.

2. Monica: the closest rival to Sider

Best for: people who want an all-in-one assistant with agents and media generation.

Monica's listing showed 3,000,000 users and 4.9 from 32.3K ratings. It opens with Cmd/Ctrl+M and describes Monica Agent, a Browser Operator that controls the browser for repetitive tasks, Deep Research, slide generation, multi-model chat, a prompt library opened with a slash, and image and video generation. Our Monica vs Merlin comparison goes feature by feature.

Weaknesses: the feature list is long enough that the sidebar can feel like a second app rather than a quick helper.

3. Merlin: a strong alternative with cross-device accounts

Best for: people who want the same assistant across Chrome, phone, and Windows.

Merlin's listing showed 900,000 users and 4.8 from 8.8K ratings. It describes summoning AI with Ctrl+M or Cmd+M from any tab, chatting with web pages, videos, and documents, and saving custom prompts for retrieval with a slash. It also says one account works across Chrome, iOS, Android, and Windows.

Weaknesses: like Sider and Monica, prompts are a side feature rather than a managed library.

4. MaxAI: a cleaner, lighter interface

Best for: people who want an AI sidebar and a right-click menu without much clutter.

MaxAI's listing showed 700,000 users and 4.7 from 14.5K ratings. It describes two surfaces: a sidebar for questions about the current page, and a context menu for selected text. Its free tier, per the listing, includes asking about pages and files, AI web search, writing and reply help, translation, and creating reusable prompts.

Weaknesses: the listing's model list names some older models, so check the current lineup in the product before buying for model access alone.

5. HARPA AI: best for automation and monitoring

Best for: people who want the sidebar to do things, not just chat.

HARPA's listing showed 400,000 users and 4.7 from 3.2K ratings. You call it with Alt+A or by typing a double slash, and it describes over 100 page-aware commands, price monitoring, data extraction, and video and PDF summaries. The listing says HARPA keeps your data locally and relies on AI APIs that don't train on your data; that's the developer's statement, so read its privacy policy for the details.

Weaknesses: the command-driven design has a learning curve if you just want to chat.

6. Gemini in Chrome: the built-in option

Best for: Chrome users who'd rather not install anything.

Google's Gemini in Chrome page describes assistance that summarizes pages, compares options across open tabs, works with Google apps, and can run tasks through "auto browse." The same page says auto browse is rolling out first in preview to Google AI Pro and Ultra subscribers in the U.S., and that other features are rolling out to eligible users in select regions.

Weaknesses: availability depends on your region and plan, and it's a Gemini-only assistant.

7. Prompt Architects: the sidebar for the prompts themselves

Best for: people who already use ChatGPT, Claude, or Gemini all day and want better prompts without leaving the chat.

This is our tool, and the only prompt sidebar on the list. Its Chrome Web Store listing showed about 1,000 users and 4.8 from 36 ratings on September 16, 2026. That's a fraction of the general sidebars' reach, and you should weigh it.

What it does inside the chat:

• Enhance. Turns a rough request into a structured prompt with a role, task, format, and constraints, with a before-and-after view.
• Insert. Drops the result straight into the chat input.
• Library. Saves prompts with tags and search.
• Global variables. {{company_name}} or {{target_audience}}, defined once and filled in wherever you use them.
• Context library. Brand guidelines or product specs you attach instead of pasting.
• Team plan. Shared prompts, variables, and context across 2 to 20 members.

Our FAQ lists variable support across ChatGPT, Claude, Gemini, Grok, Perplexity, V0, Bolt, Kimi, NotebookLM, and Base44. The free plan includes 5 enhancements a day; Pro is $4.99 a month at the time of writing, per our pricing page.

Weaknesses: it does nothing on ordinary web pages. If you want to summarize an article or draft a reply on LinkedIn, pick one of the general sidebars above.

Should you run a general sidebar and a prompt sidebar together?

Often, yes. They answer different questions. A general sidebar answers "help me with this page." A prompt sidebar answers "help me ask the chatbot well, and remember how I did it."

Two practical rules if you run both:

1. Give them different shortcuts. Monica and Merlin both list Cmd/Ctrl+M, and Promptly, a prompt tool, lists Ctrl+M too. Two extensions claiming the same shortcut is a common reason one "stops working." Chrome lets you reassign extension shortcuts at chrome://extensions/shortcuts.
2. Decide where your prompts live. If you save prompts in three places, you'll search three places. Pick one library and use the others only for their own features.

What should you test in the first week?

Listings describe features; a week of real use tells you whether a sidebar earns its space. These are the checks we'd run on any of the tools above, including ours.

1. Does the shortcut work where you actually are? Try it in your AI chat, your email, a Google Doc, and a PDF. Some pages block extensions or steal the key combination.
2. Does insert land in the right box? A sidebar that writes into the wrong field, or loses your formatting, costs more time than it saves.
3. Can you find a prompt from last Tuesday in under ten seconds? Save five prompts on day one and search for them on day five. If you can't find them, the library isn't working for you.
4. What happens when the chat site changes? AI sites update their layouts often. Note whether the sidebar keeps working after an update, and how quickly the developer fixes it when it doesn't.
5. Where do the credits go? General sidebars usually run on their own credit or query allowance. Check how fast a normal day uses it up before you pay.
6. Does it duplicate something you already pay for? If you pay for ChatGPT Plus and a sidebar's main feature is chatting with the same model, you may be paying twice for one job.

Keep the one that passes the most checks for your day, not the one with the longest feature list. Removing an extension you don't use is also a small privacy win.

How do you check an AI sidebar is safe to install?

Sidebars that read the page need broad access, which is exactly what makes them useful. That makes a five-minute check worth doing:

• Read the listing's privacy section on the Chrome Web Store, which states what data the developer says it collects.
• Read the developer's privacy policy, especially on training and retention.
• Check site access in Chrome's extension details. Many extensions let you limit access to specific sites or to "on click."
• Keep it off sensitive pages. Client records, health data, admin consoles, and banking don't need an AI panel reading them.
• Ask IT first at work. Some companies block unapproved extensions, and for good reason.

How do you choose the right AI sidebar extension?

On Edge, the options shift; our guide to Microsoft Edge extensions for ChatGPT and Copilot covers that browser. For wider shortlists, see the best free ChatGPT Chrome extensions and our test of 12 AI prompt manager extensions. And if you want AI outside the browser entirely, our Raycast AI alternatives guide covers desktop launchers.

Time your own workflow: a 10-minute test

Don't take our step count on faith. Time it. Pick five prompts you actually sent this week and run this twice, once your current way and once with a sidebar.

TAB-SWITCH TIMING TEST

Setup: one AI chat tab open. Phone stopwatch ready.
Use the same 5 real prompts in both rounds.

ROUND A - your current way
For each prompt:
  start timer
  -> find or write the prompt (notes app, doc, other tab)
  -> improve it if you normally do
  -> get it into the chat box
  stop timer when you press Send
Record: seconds per prompt, tab switches per prompt

ROUND B - with a sidebar
For each prompt:
  start timer
  -> open the sidebar
  -> pick or enhance the prompt
  -> insert it
  stop timer when you press Send
Record the same two numbers.

RESULT
Seconds saved per prompt  x  prompts per day  x  250
= seconds saved per working year. Divide by 3600 for hours.

Run round B a second time after a day of use. First-run numbers are always slower, and the honest comparison is against a tool you've learned.

The bottom line

"AI sidebar extension" covers two products that happen to share a shape. If you want AI beside every page you read, Sider and Monica lead on reach, with Merlin, MaxAI, and HARPA as real alternatives. If your time goes into writing and re-finding prompts inside the chat you already pay for, a prompt sidebar is the one that removes the tab switching you actually do.