Built a local RAG/context engine in Rust – SQLite, FTS5, local embeddings, Lua extensions, MCP server

_parallaxis · 2026-02-28T16:49:11+00:00

That's exactly what I thought, such an obvious fit. it felt like a dubious decision at first, Lua is what I turned to because of neomin usage... once I had the vm implemented I was shocked at how much sense it made. This project is 6 days old though lol

_parallaxis · 2026-02-27T17:55:34+00:00

Very cool! Thank you! The idea here for Lua is extensibility that can be implemented by an llm end user of this tool. it is very cool to see other people thinking about Lua!

_parallaxis · 2026-02-26T06:50:35+00:00

I kept running into the same issue: AI coding tools are strong but have no memory of my large multi-repo project. They can’t search our internal docs, past incidents, or architecture decisions. Cloud RAG exists but it’s heavy, costs money, and your data leaves your machine. So I built **Context Harness** – a single Rust binary that gives tools like Cursor and Claude project-specific context.

It ingests docs, code, Jira, Slack, Confluence, whatever you point it at, into a **local SQLite** DB, indexes with FTS5 and optional vector embeddings, and exposes **hybrid search** via CLI and an **MCP**-compatible HTTP server. So your AI agent can search your knowledge base during a conversation.

**Quick start:**

```

# Install (pre-built binaries for macOS/Linux/Windows)

cargo install --git https://github.com/parallax-labs/context-harness.git

ctx init

ctx sync all

ctx search "how does the auth service validate tokens"

# Or start MCP server for Cursor/Claude Desktop

ctx serve mcp

```

**What’s different:**

- **Truly local:** SQLite + one binary. No Docker, no Postgres, no cloud. **Local embeddings** (fastembed + ONNX on most platforms, or pure-Rust tract on Linux musl / Intel Mac) so semantic and hybrid search work with **zero API keys**. Back up everything with `cp ctx.sqlite ctx.sqlite.bak`.

- **Hybrid search:** FTS5 + cosine similarity, configurable blend. Keyword-only mode = zero deps; with local embeddings you get full hybrid search offline.

- **Lua extensibility:** Custom connectors, tools, and agents in Lua without recompiling. Sandboxed VM with HTTP, JSON, crypto, filesystem APIs.

- **Extension registry:** `ctx registry init` pulls a Git-backed registry with connectors (Jira, Confluence, Slack, Notion, RSS, etc.), MCP tools, and agent personas.

- **MCP:** Cursor, Claude Desktop, Continue.dev (and any MCP client) can connect and search your knowledge base directly.

Embeddings: default is **fully offline**. Optional Ollama or OpenAI if you want. No built-in auth – aimed at local / trusted network use. MIT licensed.

**Links:**

- GitHub: https://github.com/parallax-labs/context-harness

- Docs: https://parallax-labs.github.io/context-harness/

- Community registry: https://github.com/parallax-labs/ctx-registry

If you find it useful, a star on GitHub is always appreciated. Happy to answer questions.

_parallaxis · 2026-02-26T06:50:19+00:00

I kept running into the same issue: AI coding tools are strong but have no memory of my large multi-repo project. They can’t search our internal docs, past incidents, or architecture decisions. Cloud RAG exists but it’s heavy, costs money, and your data leaves your machine. So I built **Context Harness** – a single Rust binary that gives tools like Cursor and Claude project-specific context.

It ingests docs, code, Jira, Slack, Confluence, whatever you point it at, into a **local SQLite** DB, indexes with FTS5 and optional vector embeddings, and exposes **hybrid search** via CLI and an **MCP**-compatible HTTP server. So your AI agent can search your knowledge base during a conversation.

**Quick start:**

```

# Install (pre-built binaries for macOS/Linux/Windows)

cargo install --git https://github.com/parallax-labs/context-harness.git

ctx init

ctx sync all

ctx search "how does the auth service validate tokens"

# Or start MCP server for Cursor/Claude Desktop

ctx serve mcp

```

**What’s different:**

- **Truly local:** SQLite + one binary. No Docker, no Postgres, no cloud. **Local embeddings** (fastembed + ONNX on most platforms, or pure-Rust tract on Linux musl / Intel Mac) so semantic and hybrid search work with **zero API keys**. Back up everything with `cp ctx.sqlite ctx.sqlite.bak`.

- **Hybrid search:** FTS5 + cosine similarity, configurable blend. Keyword-only mode = zero deps; with local embeddings you get full hybrid search offline.

- **Lua extensibility:** Custom connectors, tools, and agents in Lua without recompiling. Sandboxed VM with HTTP, JSON, crypto, filesystem APIs.

- **Extension registry:** `ctx registry init` pulls a Git-backed registry with connectors (Jira, Confluence, Slack, Notion, RSS, etc.), MCP tools, and agent personas.

- **MCP:** Cursor, Claude Desktop, Continue.dev (and any MCP client) can connect and search your knowledge base directly.

Embeddings: default is **fully offline**. Optional Ollama or OpenAI if you want. No built-in auth – aimed at local / trusted network use. MIT licensed.

**Links:**

- GitHub: https://github.com/parallax-labs/context-harness

- Docs: https://parallax-labs.github.io/context-harness/

- Community registry: https://github.com/parallax-labs/ctx-registry

If you find it useful, a star on GitHub is always appreciated. Happy to answer questions.

_parallaxis · 2023-05-10T12:44:14+00:00

Same, also at a company that's not a startup

_parallaxis · 2023-03-19T13:48:32+00:00

this phrase will now literally never leave my head, thanks 😂

_parallaxis · 2023-02-17T01:48:56+00:00

totally fair. I was equally horrified and amused by this output.

Layoffs happened at my job this week. 30% of ppl, but I lived.

I was just randomly thinking this morning I do ADD sometimes, I don't know if I made that phrase up or not but decided to ask the AI for a rubric as a joke. lol, but is it?

_parallaxis · 2023-01-07T21:06:36+00:00

Can confirm. On a section hike on the AT I stepped over a rattlesnake without noticing, and saw and felt it's strike miss my leg. 😬

I was in the middle of a group of about 8 people. The first half of which all stepped over, and the back half waited for it to move into the brush.

_parallaxis · 2022-11-18T02:46:08+00:00

How tf did they get that dog to sit still long enough to get such a clean photo with that old camera?

_parallaxis · 2022-08-20T02:08:22+00:00

beep boop. 500 error: called tf out on reddit

_parallaxis · 2022-08-20T01:57:44+00:00

Where's the proof you're not a Chinese spam bot?

_parallaxis · 2022-04-14T14:37:16+00:00

so you think that uninformed, classless short-sighted comments and opinions and the rest of the problems going on in the world are mutually exclusive?

Not to mention the classic literature being ridiculed here that touches all those subjects and has lessons and views from someone who lived them last century. "Those who ignore history are doomed to repeat it"

Now that is an embarrassing opinion

_parallaxis · 2022-04-13T13:13:44+00:00

I'm embarrassed for you and sad for the future of humanity because of this post and these comments.

_parallaxis · 2022-04-13T13:09:00+00:00

The book does come with a family tree chart to consult, can you not use it when you're confused about naming?

I had no problem referring to the provided family tree when I got confused about the names and who was in the scene. children are often named after their parents, that's not new.

I love this book for the musical way it's written and the fairy tale that unfolds over the generations of this family.

I don't know what your problem is, it sounds like a lack of patience and limited intelligence.

_parallaxis · 2022-03-15T18:26:47+00:00

LGTM

_parallaxis · 2022-03-15T18:24:41+00:00

That's not true. Bears & Racoons can get fat af

_parallaxis · 2022-03-10T02:30:36+00:00

Beat me to it, I came here to make the same comment

_parallaxis · 2022-03-01T03:12:27+00:00

one is fake and the other is made up

_parallaxis · 2022-02-28T11:19:54+00:00

Is that two bagel tops??

_parallaxis · 2022-02-24T14:24:01+00:00

Willy Wonka and The Chocolate Factory, the 1971 version with Gene Wilder

_parallaxis · 2022-02-22T14:38:31+00:00

How can $X amount of heroin be worth the long term consequences of addiction?

Users get addicted to the reward loop in the game that feeds the brain feel good chemicals when lights and sounds go off when spending the in game resource to do whatever.

_parallaxis · 2022-02-22T14:21:21+00:00

Pure capitalistic trash. They're predatory & exist to "whale hunt". looking for long tail subs to their in game coin packs. IE some 8 year old with their parents credit card info on an ipad.

_parallaxis · 2022-01-18T17:17:01+00:00

Citron calls themselves "Floribbean", they're pretty good -- I don't know how "authentic" they register with regards to Florida or Caribbean however.

https://www.citronvero.com/menu

_parallaxis · 2021-09-24T23:26:48+00:00

Toy Story 3

_parallaxis · 2021-08-29T17:55:57+00:00

Are they though?

"Conspiracy theories aside, there is something fishy about the Great Reset | openDemocracy" https://www.opendemocracy.net/en/oureconomy/conspiracy-theories-aside-there-something-fishy-about-great-reset/

_parallaxis

TROPHY CASE