Lacis — branching AI conversations in your editor

Every message is a node. Every reply can fork into N branches. The model only ever sees the chain of ancestors of the current node — never the parallel branches. Explore alternatives without polluting your context window.

It's git branch, but for your AI conversations — right inside VS Code, Cursor, Windsurf, VSCodium and other compatible editors.

And a context tree that travels with you: define your identity, rules and skills once, and Lacis injects only the relevant pieces into every reply, on every branch.

Why a tree?

Linear chat forces every tangent into one ever-growing thread. The model re-reads the whole history each turn, and unrelated detours bleed into each other. Lacis lets you branch: ask a follow-up as a sibling, try three prompts in parallel, keep a clean main line. Each branch sends only its own ancestor chain — cheaper, sharper, and easier to navigate.

This works the same whatever model you run it on.

Context that follows you

This is the heart of Lacis. Set up a small context tree once — typed branches for your identity, your rules, your skills — and Lacis routes them automatically: each reply pulls in only the branches relevant to what you just asked, on every branch of every conversation. A banner shows exactly which context was loaded, so it's never a black box.

Your standards and who-you-are are always present, without re-pasting them into every prompt — and without bloating the context with things that don't apply.

Bring your model

Lacis is provider-agnostic. Pick whichever path fits your editor:

• GitHub Copilot (VS Code) — if you have a Copilot subscription, Lacis uses it through the official vscode.lm API. No API key, no configuration.
• Your own API key (everywhere, including Cursor / Windsurf / VSCodium) — point Lacis at OpenAI, Anthropic, or any OpenAI-compatible endpoint. Your key is stored in the OS secret store, never sent anywhere but your provider.

On editors without Copilot (Cursor, Windsurf, VSCodium, Theia…), use the API key path — it's first-class, not a fallback.

Features

• Context tree (auto-routed) — reusable identity / rules / skills branches, injected into a reply only when relevant. Set your context once; it follows every branch, and a banner shows what was loaded.
• Branch anywhere — fork from any message to try another approach, and keep both side by side.
• Clean context per branch — the model only sees the current path, never the sibling branches. Less noise, sharper answers.
• Editor integration — ask about the current selection, file, or diagnostics; insert the last response at the cursor.
• Tree view, focus mode, tags, bookmarks, search — navigate large trees fast.
• Local by default — no account, no cloud. Your conversations stay on your machine.

Getting started

1. Install the extension.
2. Run Lacis: Open Tree from the Command Palette (⌘/Ctrl+Shift+P), or press ⌘/Ctrl+Shift+T.
3. Choose your model:
   • Have Copilot? You're ready — Lacis picks it up automatically.
   • No Copilot (or on Cursor/Windsurf)? Open Settings in the panel and add a provider: base URL + API key + model.
4. Type a message. Press ⏎ to send, Shift+⏎ for a newline. Use / for slash commands (/note, /focus, /help).

That's it. Hit Branch on any reply to explore a second approach.

Commands

Settings

Telemetry

Lacis collects anonymous, structure-only usage data (tree shape, token counts, model/provider IDs, feature usage) to guide development. It never collects message content, titles, tags, file paths, or keys.

Collection happens only when both your editor's global telemetry setting is on and the lacis.telemetry.enabled toggle is on (default). Setting either to off stops all collection immediately. The only identifier is your editor's anonymous machineId.

👉 Full disclosure (every event, every field) and configuration instructions: see TELEMETRY.md, bundled with this extension and in the repository under packages/vscode/.

Privacy

The model only ever receives the ancestor chain of the current node. Your API keys and provider URLs stay in your editor's secret store and are never transmitted to telemetry. Conversations are stored locally in the extension's storage.

Built by GengAd. Issues and feedback welcome.