Flecten

The desktop workspace for coding agents.
Conversations, files, tools, and changes in one window.

English · 简体中文 · Português (Brasil) · Español · 日本語 · Українська · Русский

_{Preview running on a local demo provider.}

[!WARNING]
Alpha. Flecten is early: there are a lot of bugs and a lot of unfinished pieces right now. Over the coming days I'm putting maximum effort into polishing and tightening everything up. Expect fast changes, and please report what breaks.

⚡ Why Flecten

The agent loop is table stakes. Flecten fixes what breaks after the demo.

20 built-in tools  ·  4 provider protocols  ·  7 interface languages  ·  85% coverage gate

🚀 Quick start

Requires Bun 1.4 or newer.

bun install
export OPENAI_API_KEY=...
bun run app:dev

bun run app:dev starts Vite, launches the core on Bun, and opens an Electron window with hot reload. The current directory is the project root; set FLECTEN_CWD to work elsewhere.

# or another provider
FLECTEN_PROVIDER=anthropic FLECTEN_MODEL=claude-sonnet-4-6 bun run app:dev

To inspect the UI in a browser without the core, run bun run dev:ui.

✨ What makes Flecten different

🗣️ Talk while it works

Keep talking while the Worker runs.
New chats split into a Talker in your language and a Worker on a focused assignment. Steer mid-task, ask questions, or stop just the Worker. Every call is a live card with its own log and stop button.

🖥️ A full IDE, one toggle away

Agent and IDE in the same window.
Flip the header to IDE: file tree, editor tabs, project search and replace, go to line, source control, terminal. The conversation stays available as an island.

🩹 Diffs you can trust

Review every edit. Undo without git surgery.
Each change lands as a reviewable diff; accept or discard per file. Saving checks the on-disk version, so a conflict never clobbers your draft. Checkpoints and a shadow git power /undo and /redo.

🧠 Memory that survives the chat

Your project, remembered across sessions.
The model decides what to keep: preferences, lessons, decisions. Each entry is backed by your own words, versioned, and organized by topic. Stale entries invalidate themselves.

📖 A dictionary for your terms

Your vocabulary, resolved before the model is called.
A public design and AI dictionary syncs from GitHub; local project terms win. Fuzzy matching even fixes layout typos: мшиусщвштп → vibecoding. Your message stays word for word.

🔌 Providers in one click

Pick from a catalog, not a JSON file.
Add a known service with logos and model lists, or point at your own server. Flecten probes the connection and discovers models. Four protocols, with visible failover when one drops.

📊 Answers that are live HTML

A result you can interact with, not just read.
Final answers can be sandboxed HTML: sortable tables, tabs, charts, and buttons that open settings or a file. Rendered as it streams, with no network and no external scripts.

🪞 It learns your voice

A Twin that works like you, not like a generic assistant.
It learns from your past sessions and sources, writes specs in your terms, and rejects work that is not yours. Memory and a profile close the loop.

✅ And everything else you would expect

🏗️ Architecture

The UI never reads files or calls models. It sends commands to a Bun sidecar over a JSONL protocol and receives typed events back. The core never imports Electron or the UI.

flowchart LR
  U[You] --> UI[Svelte 5 UI]
  UI <-->|commands / events| SC[Sidecar on Bun]
  SC <--> CORE[Agent core]
  CORE --> PROV[Providers<br/>OpenAI · Anthropic · Gemini]
  CORE --> TOOLS[20 tools + Skills + MCP]
  TOOLS --> SEC[Security<br/>permissions · sandbox · hooks]
  CORE --> STORE[(events.jsonl<br/>checkpoints · shadow git)]

Events carry seq, ts, and schemaVersion, so a reopened window rebuilds the task from events.jsonl and catches up with the live stream from its cursor.

🔗 Connect your stack

The default provider is openai with gpt-5.1. Keys come from environment variables: OPENAI_API_KEY, ANTHROPIC_API_KEY, OPENROUTER_API_KEY, DEEPSEEK_API_KEY. Any compatible service can be added in the window or in flecten.config.json:

{
  "provider": "local",
  "model": "qwen3-coder",
  "providers": {
    "local": {
      "protocol": "openai-chat",
      "baseUrl": "http://127.0.0.1:11434/v1"
    }
  }
}

A provider without a key works without authentication, which suits local servers. Advanced fields set headers, proxy, and transportTimeoutMs; a key can come from apiKeyEnv or an auth.command. Pick a reasoning level in the composer: auto, low, medium, high.

• 🧩 Skills load from ~/.agents/skills and the project's .agents/skills; the model sees a catalog and opens a full SKILL.md on demand.
• 🔌 MCP servers expose their tools, resources, and prompts, with OAuth discovery and PKCE.
• 🪝 Hooks can block startup, a prompt, or a tool; a failClosed hook blocks the action when it crashes.
• 📦 Modules bundle tools, instructions, hooks, and services, activated per task after content review.

{
  "mcp": {
    "servers": {
      "docs": { "command": "bun", "args": ["mcp/docs-server.ts"] }
    }
  },
  "hooks": {
    "preToolUse": [
      { "command": "bun .agents/hooks/guard.ts", "matcher": "bash" }
    ]
  }
}

⚠️ Project configuration with MCP, hooks, or skills launches processes. Only open it in a repository you trust.

Full contract: docs/EXTENSIONS.md.

⌨️ Commands

A change is not ready until it passes bun run verify.

📚 Documentation

• 🏗️ Architecture · 🗣️ Talker and Worker · 🧠 Memory · 📖 Dictionary
• 🧩 Extensions · 📦 Modules · 🎙️ Voice
• 🗂️ Structure · 🎨 Design · 📐 Conventions
• 🚢 Release · 📝 Changelog · 🖼️ UI guidelines · 🐚 Shell guidelines

🚦 Status

The agent foundation works and is covered by tests and snapshots. Still in progress: release signing, the Windows sandbox, per-command resource isolation, and native platform acceptance testing. Windows PTY uses ConPTY from Bun 1.4.2.

Auto-update uses FLECTEN_UPDATE_URL and verifies an Ed25519 manifest with an embedded public key before downloading the installer.

🤝 Contributing

Before opening a PR, read CONTRIBUTING.md and CODE_OF_CONDUCT.md. Report vulnerabilities according to SECURITY.md, not in a public issue.

📄 License

AGPL-3.0. See LICENSE. Free to use, modify, and share; community norms live in ETHICS.md and the Code of Conduct.

_{Flecten was previously called Liquid Harness. Existing liquid.config.json files, LIQUID_* variables, liquid-harness:// links, and saved profiles still work. The primary names are now flecten.config.json, FLECTEN_*, and flecten://. The .liquid/ folder keeps sessions, attachments, and checkpoints without a data migration.}

_{The interface starts in English. Choose a language in Settings → General → Interface language. The choice is saved on this device and is separate from the language of agent replies.}