lattis 0.4.0

A pluggable agent toolkit (server + TUI + web UI)

Lattis

Lattis is a pluggable agent toolkit built on pydantic-ai: a FastAPI server with a Textual TUI and a bundled web UI. Agents are loaded as plugins, and each thread can select a different agent.

What you get

• Server + clients: FastAPI API, Textual TUI, and a web UI (served by the same server).
• Pluggable agents: built-ins, third-party entry points, or local module:attribute specs.
• Per-thread agent selection: pick an agent per thread (TUI + web UI + API).
• Persistent state: thread history in SQLite, plus a workspace directory for agents that write files/tools.

Requirements

• uv
• Python 3.14+ (uv can install it automatically)
• An API key for at least one model provider (Gemini, Anthropic, OpenAI, etc.)

Quick start

uv sync
uv run lattis

Run the server (API + web UI):

uv run lattis server

Then open http://localhost:8000.

CLI

lattis                 # Run the TUI (default)
lattis tui             # Run the TUI explicitly
lattis server          # Run the API server (and web UI, if built)

lattis tui

--server <url>          Connect to a specific server URL
--local                 Force local mode (skip server auto-discovery)
--agent <id|name>       Default agent for local/in-process mode
--agents <specs>        Extra plugins (comma-separated `module:attr` specs) for local/in-process mode

By default, the TUI auto-discovers a server on http://127.0.0.1:8000 and connects if it matches the current project; otherwise it runs in local (in-process) mode.

lattis server

--host <host>           Host interface to bind (default: 127.0.0.1)
--port <port>           Port to bind (default: 8000)
--reload                Enable auto-reload
--workspace             Workspace mode: local | central
--agent <id|name>       Default agent id or name
--agents <specs>        Extra plugins (comma-separated `module:attr` specs)

Agents

Built-in agents:

• binsmith — a script-building developer agent that can write reusable, composable tools
• poetry — a simple example agent

Select an agent per thread

• TUI: use /agent, /agent list, /agent set <id|number>, /agent default
• Web UI: use the sidebar agent selector
• API: PATCH /sessions/{session_id}/threads/{thread_id}/state with {"agent": "<id-or-name>"} (or null to reset)

Client integration

See docs/client-integration.md for the thin-client API flow (bootstrap, thread state, model options, streaming).

Add your own agent plugins

Lattis discovers agents automatically from:

1. lattis.agents.builtins (included with Lattis)
2. Python entry points in the group lattis.agents
3. Extra module:attribute specs via AGENT_PLUGINS / --agents

Entry point example (pyproject.toml in your plugin package):

[project.entry-points."lattis.agents"]
my-agent = "my_package.my_agent:plugin"

Your plugin can be:

• an AgentPlugin, or
• a pydantic_ai.Agent, or
• a callable that returns an Agent (optionally taking model).

Storage

Workspace modes:

• local (default): per-project .lattis/ under the current directory
• central: ~/.lattis/

Typical layout:

.lattis/
  lattis.db
  session_id
  workspace/

Configuration

Variable	Default	Description
AGENT_DEFAULT	binsmith	Default agent id/name (server + local mode)
AGENT_PLUGINS	(unset)	Extra plugins (module:attr, comma-separated)
LATTIS_WORKSPACE_MODE	local	local (per-project) or central (~/.lattis)
LATTIS_SERVER_URL	(unset)	Server URL for clients that connect over HTTP
LATTIS_PROJECT_ROOT	(cwd)	Project root used for local storage mode
LATTIS_DATA_DIR	(derived)	Override the data directory
LATTIS_WORKSPACE_DIR	(derived)	Override the workspace directory
LATTIS_DB_PATH	(derived)	Override the SQLite DB path
LATTIS_SESSION_FILE	(derived)	Override the session id file path
LATTIS_SESSION_ID	(unset)	Force a specific session id

Web UI development

The server serves the web UI from lattis/web/static when it exists.

cd frontend
npm install
npm run build