You solved a problem with ChatGPT three weeks ago. The answer was perfect. Today you need that exact fix again, and it’s gone. You don’t remember what you named the chat, which assistant you used, or whether it was even this month. So you re-ask the question, get a slightly different answer, and waste 15 minutes you didn’t have.
Multiply that by every prompt you’ve ever typed across ChatGPT, Claude, Gemini, and Perplexity. That’s the mess piling up in your AI chat history, and a free browser extension called LLMnesia is built to clean it up. It puts one search bar across everything, and your data stays on your machine.
What LLMnesia actually does
LLMnesia is a free Chrome and Edge extension that indexes your AI conversations locally in your browser. After a quick import, you press Ctrl+Shift+9 (Cmd on Mac) from any page, type a few words, and get results from every supported assistant at once. Click a result and you land on the exact message, not just the top of some chat you vaguely remember.
The search is semantic, which is the part that makes it feel like magic. You don’t need to recall the exact keyword. Type “that masonry fix” and it finds the conversation where you worked out a brick repointing problem, even if the word masonry never appeared in your prompt. For anyone whose AI chat history has become a second (or fifth) brain, this is the missing search layer.
Here’s the feature list that matters in daily use:
- One keystroke search across ChatGPT, Claude, Gemini, Perplexity, Copilot, DeepSeek, Grok, Mistral, Kimi, Qwen, and more
- One-click import of existing history from nine assistants, or load a ChatGPT data export if yours is huge
- Auto-capture of new conversations in the background, prompts and answers both
- Chats survive deletion: if the platform wipes something, your local copy still opens
- Star the chats you revisit so they never get cleaned up
- A local MCP connection that lets desktop AI like Claude Code or Cursor search your history too
That last one is more useful than it sounds. You can ask Claude Code a question and it can pull context from conversations you had in Gemini last month, then cite the source chat (we showed how to wire Claude Code to your notes a while back; this goes one step further). Your scattered AI chat history becomes one searchable workspace.
The privacy story, verified
The pitch is “local-first,” which gets thrown around a lot. Here’s what it means in practice: the search index lives in your browser’s IndexedDB storage, and the free search uploads nothing. No account required. No cloud copy. The founder’s page states it plainly: “Free search uploads nothing, ever.”
There is one paid add-on called Vault. It syncs your history across devices and keeps an encrypted backup, for £8 a month or £88 a year. Data gets encrypted on your device before upload, so the company says it stores ciphertext it can’t read. Do you need it? Only if you use multiple computers or want disaster insurance. The search works completely without it. If you got twitchy reading about AI note-takers recording your meetings, this local-first design is the direct answer to that worry.
| Feature | Free local search | Vault (£8/mo) |
|---|---|---|
| Search all AI chats | Yes | Yes |
| Data stays on device | Yes | Synced, E2E encrypted |
| Import old history | Yes | Yes |
| Backup if your laptop dies | No | Yes |
| Ask Vault (AI over history) | No | Yes |
| Account required | No | Yes |
Setting expectations: this extension is young. The Chrome Web Store listing shows a few hundred users and a 4.3 rating from a handful of reviews. It’s early-stage software from an independent founder, not an established vendor. Because everything is local, the downside of a buggy update is small. Still, treat it like a beta tool, and don’t let it be your only backup of anything critical.
Setting it up in about two minutes
The whole setup takes less time than making coffee.
- Install the LLMnesia extension from the Chrome Web Store or Edge Add-ons (no account needed)
- Open it once and run the one-click import for the assistants you use; ChatGPT, Claude, Gemini, Perplexity, DeepSeek, Grok, Character.AI, Z.ai, and Meta AI import existing history
- Just keep chatting as usual, since supported tools index automatically from then on
- Press Ctrl+Shift+9 anywhere and search for something you remember from an old chat
- Star the conversations you know you’ll need again
Step 2 is where the payoff lands for most people. Importing a year of history takes a few minutes for normal accounts, and suddenly your whole AI chat history is searchable again. If your history is enormous, export your ChatGPT data from your account settings and load that file instead.
Three ways this saves real time
The obvious win is retrieval. You stop re-asking questions you already paid for with tokens and patience. One search instead of ten minutes of scrolling through sidebar entries named “New chat (3)”.
The second win is continuity. Your AI chat history follows you: right-click any saved conversation and continue it in a different assistant, with the full thread carried over. A local summarizer can even condense a 40-turn chat before it moves, which keeps context tight. Switching from ChatGPT to Claude mid-project stops meaning starting over.
The third is the one nobody markets: durability. Platforms delete things. Accounts get flagged. Chats get lost to sync bugs. With auto-capture on, every conversation you have is copied to your own machine, so your AI chat history stops being something a company can take away. If you want a permanent, self-hosted research library instead of chat logs, that’s the same itch behind SurfSense. For people keeping client work or anything with real stakes in these tools, durability alone justifies the install.
Who should skip it
If you use one assistant casually a few times a week, your sidebar search is probably fine, and you don’t need another extension. Skip it if you’re on a locked-down work machine where extensions need IT approval, since that approval won’t come.
But if you juggle several AI tools daily, and your history is genuinely part of how you work, this is the tool that’s been missing. It costs nothing, requires no account, and sends nothing anywhere. Hard to beat that price.
The takeaway
Install LLMnesia, import your history, and press Ctrl+Shift+9 to find something you thought was gone. It takes two minutes, and the moment it saves you from re-solving one problem, it’s paid for itself. Your prompts are work product; start treating them that way.
