Every time I open a new Claude Code or Cursor session on a project I've worked on for weeks, it starts from zero. It has to re-read files, re-grep the structure, re-guess what exists — every single session, forever. And when it tells me something about my codebase, I have no real way to check if it's true or just a plausible-sounding guess.
That's what Rune fixes. It's a small runtime that sits underneath your AI coding tools, keeps a persistent "understanding graph" of your codebase up to date as you edit, and exposes it over MCP so any AI client can query it instead of re-deriving everything cold.
The part I actually care about: every answer traces back to real evidence, not an assertion. Here's real output from my own repo tonight, asking for an architecture summary:
Code
$ rune explain derived_1
{
"type": "architecture_summary",
"description": "Detected stack: Express, React. 2 React component(s),
10 Express route(s) across the scanned source tree.",
"confidence": "high",
"evidenceChain": [
{ "type": "react_component", "file": "components/UserCard.jsx",
"line": 3, "evidence": "export function UserCard({ user }) {" },
{ "type": "express_route", "method": "POST", "routePath": "/",
"file": "routes/users.js", "line": 8,
"evidence": "router.post(\"/\", (req, res) => {" },
... 10 more, each with file + line + exact matched code
]
}
It's not just claiming "this is an Express + React app" — it's showing exactly which facts, at which files and lines, prove it.
Shipped an upgrade tonight moving the core extractor (imports, components, hooks) from regex pattern-matching to a real AST parser (Babel) — more accurate detection, fewer false positives. Route detection (Express/Next.js) is still regex for now — that's next, not hidden.
Feedback welcome, especially on where it breaks.
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[ 0.21 ms ] story [ 3.4 ms ] threadIt's not just claiming "this is an Express + React app" — it's showing exactly which facts, at which files and lines, prove it. Shipped an upgrade tonight moving the core extractor (imports, components, hooks) from regex pattern-matching to a real AST parser (Babel) — more accurate detection, fewer false positives. Route detection (Express/Next.js) is still regex for now — that's next, not hidden. Feedback welcome, especially on where it breaks.