Once

What inspired me

Alexa is useful in one conversation and blank in the next. You tell it where something is, or that a plan changed, and later it acts like you never said it.

I did not want an app for one kitchen or one patient. I wanted a memory you can use for anything. Home, work, or a note you say once. The name is Once, because you should only have to say it once.

What it does

You say a fact in your own words. Later you ask a question, as if it is a new conversation. Once answers from what you said.

If you correct the fact, the new one wins. If you forget it, that memory is gone. The answer is not written in advance.

How I built it

Once has two parts.

The page is a website. You type, or you use the mic. You press Say it to store a line, then Check to ask a question.

Behind the page is a memory server written in Python. The page talks to it with MCP, the plug an assistant uses. The memory engine is Cognee, which is open source (Apache-2.0). Cognee saves the words as facts and can search them. A language model reads those facts and answers. I built the page, the server, and the way a new fact replaces an old one. I did not write Cognee.

The memory server is also on Azure, so it is not only on my laptop. The code is at github.com/tsj2003/once.

Challenges

The first demo felt fake, because a button told a fixed story instead of storing my words. I removed that. Say it now stores only the line you type or speak.

A newer fact could lose to an older one. I keep the lines in order, oldest first, and the later line wins when they disagree.

After forget, the next question crashed because the dataset was already gone. It now says that nothing stored answers that yet.

Putting the server on Azure took more than one try. An early deploy did not pick up the new code. A later deploy did, and a public check stored a place, answered from the new place, then returned nothing after forget.

What I learned

A memory demo is only real if a stranger’s sentence goes in and a different question comes back out. Saying which part I built, and which part is Cognee, matters as much as the feature.

Built With

• app
• azure
• cognee
• css
• express.js
• graph
• html
• http
• javascript
• knowledge
• mcp
• node.js
• openai
• python
• service
• speech
• streamable
• typescript
• uvicorn
• vite
• web
• zod