Files
vessel/README.md
vikingowl edd7c94507 docs: comprehensive documentation update
Updates README with:
- System prompts feature (model-specific, capability-based defaults)
- Custom model creation with embedded prompts
- Comprehensive Custom Tools Guide with examples
- Updated API reference with all endpoints
- Updated roadmap with completed features

Adds detailed documentation for custom tools:
- JavaScript, Python, and HTTP tool types
- Parameter definitions and templates
- Testing workflow and security notes
- Complete weather tool example
- Programmatic tool creation guide
2026-01-03 21:19:32 +01:00

21 KiB

Vessel

Vessel

A modern, feature-rich web interface for Ollama

Why VesselFeaturesScreenshotsQuick StartInstallationRoadmap

SvelteKit 5 Svelte 5 Go 1.24 TypeScript Tailwind CSS Docker

License GPL-3.0 PRs Welcome


Why Vessel

Vessel and open-webui solve different problems.

Vessel is intentionally focused on:

  • A clean, local-first UI for Ollama
  • Minimal configuration
  • Low visual and cognitive overhead
  • Doing a small set of things well

It exists for users who want a UI that is fast and uncluttered, makes browsing and managing Ollama models simple, and stays out of the way once set up.

open-webui aims to be a feature-rich, extensible frontend supporting many runtimes, integrations, and workflows. That flexibility is powerful — but it comes with more complexity in setup, UI, and maintenance.

In short

  • If you want a universal, highly configurable platform → open-webui is a great choice
  • If you want a small, focused UI for local Ollama usage → Vessel is built for that

Vessel deliberately avoids becoming a platform. Its scope is narrow by design.


Features

Core Chat Experience

  • Real-time streaming — Watch responses appear token by token
  • Conversation history — All chats stored locally in IndexedDB
  • Message editing — Edit any message and regenerate responses with branching
  • Branch navigation — Explore different response paths from edited messages
  • Markdown rendering — Full GFM support with tables, lists, and formatting
  • Syntax highlighting — Beautiful code blocks powered by Shiki with 100+ languages
  • Dark/Light mode — Seamless theme switching with system preference detection

System Prompts

  • Prompt library — Save and organize reusable system prompts
  • Model-specific prompts — Assign default prompts to specific models
  • Capability-based defaults — Auto-select prompts based on model capabilities (vision, tools, thinking, code)
  • Quick selection — Switch prompts mid-conversation with the prompt selector

Built-in Tools (Function Calling)

Vessel includes five powerful tools that models can invoke automatically:

Tool Description
Web Search Search the internet for current information, news, weather, prices
Fetch URL Read and extract content from any webpage
Calculator Safe math expression parser with functions (sqrt, sin, cos, log, etc.)
Get Location Detect user location via GPS or IP for local queries
Get Time Current date/time with timezone support

Custom Tools

Create your own tools that models can invoke:

  • JavaScript tools — Run in-browser with full access to browser APIs
  • Python tools — Execute on the backend with any Python libraries
  • HTTP tools — Call external REST APIs (GET/POST)
  • Built-in templates — Start from 8 pre-built templates
  • Test before saving — Interactive testing panel validates your tools

See the Custom Tools Guide for detailed documentation.

Model Management

  • Model browser — Browse, search, and pull models from Ollama registry
  • Custom models — Create models with embedded system prompts
  • Edit custom models — Update system prompts of existing custom models
  • Live status — See which models are currently loaded in memory
  • Quick switch — Change models mid-conversation
  • Model metadata — View parameters, quantization, and capabilities
  • Update detection — See which models have newer versions available

Developer Experience

  • Beautiful code generation — Syntax-highlighted output for any language
  • Copy code blocks — One-click copy with visual feedback
  • Scroll to bottom — Smart auto-scroll with manual override
  • Keyboard shortcuts — Navigate efficiently with hotkeys

Screenshots

Chat Interface - Dark Mode
Clean, modern chat interface
Code Generation
Syntax-highlighted code output
Web Search Results
Integrated web search with styled results
Light Mode
Light theme for daytime use
Model Browser
Browse and manage Ollama models

Quick Start

Prerequisites

  • Docker and Docker Compose
  • Ollama installed and running locally

Ollama Configuration

Ollama must listen on all interfaces for Docker containers to connect. Configure it by setting OLLAMA_HOST=0.0.0.0:

Option A: Using systemd (Linux, recommended)

sudo systemctl edit ollama

Add these lines:

[Service]
Environment="OLLAMA_HOST=0.0.0.0"

Then restart:

sudo systemctl daemon-reload
sudo systemctl restart ollama

Option B: Manual start

OLLAMA_HOST=0.0.0.0 ollama serve

One-Line Install

curl -fsSL https://somegit.dev/vikingowl/vessel/raw/main/install.sh | bash

Or Clone and Run

git clone https://somegit.dev/vikingowl/vessel.git
cd vessel
./install.sh

The installer will:

  • Check for Docker, Docker Compose, and Ollama
  • Start the frontend and backend services
  • Optionally pull a starter model (llama3.2)

Once running, open http://localhost:7842 in your browser.


Installation

The install script handles everything automatically:

./install.sh              # Install and start
./install.sh --update     # Update to latest version
./install.sh --uninstall  # Remove installation

Requirements:

  • Ollama must be installed and running locally
  • Docker and Docker Compose
  • Linux or macOS

Option 2: Docker Compose (Manual)

# Make sure Ollama is running first
ollama serve

# Start Vessel
docker compose up -d

Option 3: Manual Setup (Development)

Prerequisites

Frontend

cd frontend
npm install
npm run dev

Frontend runs on http://localhost:5173

Backend

cd backend
go mod tidy
go run cmd/server/main.go -port 9090

Backend API runs on http://localhost:9090


Configuration

Environment Variables

Frontend

Variable Default Description
OLLAMA_API_URL http://localhost:11434 Ollama API endpoint
BACKEND_URL http://localhost:9090 Vessel backend API

Backend

Variable Default Description
OLLAMA_URL http://localhost:11434 Ollama API endpoint
PORT 8080 Backend server port
GIN_MODE debug Gin mode (debug, release)

Docker Compose Override

Create docker-compose.override.yml for local customizations:

services:
  frontend:
    environment:
      - CUSTOM_VAR=value
    ports:
      - "3000:3000"  # Different port

Architecture

vessel/
├── frontend/               # SvelteKit 5 application
│   ├── src/
│   │   ├── lib/
│   │   │   ├── components/ # UI components
│   │   │   ├── stores/     # Svelte 5 runes state
│   │   │   ├── tools/      # Built-in tool definitions
│   │   │   ├── storage/    # IndexedDB (Dexie)
│   │   │   └── api/        # API clients
│   │   └── routes/         # SvelteKit routes
│   └── Dockerfile
│
├── backend/                # Go API server
│   ├── cmd/server/         # Entry point
│   └── internal/
│       ├── api/            # HTTP handlers
│       │   ├── fetcher.go  # URL fetching with wget/curl/chromedp
│       │   ├── search.go   # Web search via DuckDuckGo
│       │   └── routes.go   # Route definitions
│       ├── database/       # SQLite storage
│       └── models/         # Data models
│
├── docker-compose.yml      # Production setup
└── docker-compose.dev.yml  # Development with hot reload

Tech Stack

Frontend

Backend


Development

Running Tests

# Frontend unit tests
cd frontend
npm run test

# With coverage
npm run test:coverage

# Watch mode
npm run test:watch

Type Checking

cd frontend
npm run check

Development Mode

Use the dev compose file for hot reloading:

docker compose -f docker-compose.dev.yml up

API Reference

Backend Endpoints

Method Endpoint Description
POST /api/v1/proxy/search Web search via DuckDuckGo
POST /api/v1/proxy/fetch Fetch URL content
GET /api/v1/location Get user location from IP
POST /api/v1/tools/execute Execute Python/JS tools
GET /api/v1/models/local List local models with filtering
GET /api/v1/models/local/updates Check for model updates
GET /api/v1/models/remote Browse Ollama model registry
POST /api/v1/models/remote/sync Sync registry from ollama.com
POST /api/v1/chats Create new chat
GET /api/v1/chats/grouped List chats grouped by date
POST /api/v1/sync/push Push local changes to backend
GET /api/v1/sync/pull Pull changes from backend

Ollama API Proxy

All Ollama API endpoints are proxied through /api/v1/ollama/*:

Method Endpoint Description
GET /api/v1/ollama/api/tags List installed models
POST /api/v1/ollama/api/show Get model details
POST /api/v1/ollama/api/pull Pull a model (streaming)
POST /api/v1/ollama/api/create Create custom model (streaming)
DELETE /api/v1/ollama/api/delete Delete a model
POST /api/v1/ollama/api/chat Chat completion (streaming)
POST /api/v1/ollama/api/embed Generate embeddings

Custom Tools Guide

Vessel allows you to create custom tools that LLMs can invoke during conversations. Tools extend the model's capabilities beyond text generation.

Creating a Tool

  1. Navigate to Tools in the sidebar
  2. Click Create Custom Tool
  3. Fill in the tool details:
    • Name — Unique identifier (alphanumeric + underscores)
    • Description — Explains to the model when to use this tool
    • Parameters — Define inputs the model should provide
    • Implementation — Choose JavaScript, Python, or HTTP
    • Code/Endpoint — Your tool's logic

Tool Types

JavaScript Tools

JavaScript tools run directly in the browser. They have access to browser APIs and execute instantly.

// Example: Format a date
// Parameters: { date: string, format: string }

const d = new Date(args.date);
const formats = {
  'short': d.toLocaleDateString(),
  'long': d.toLocaleDateString('en-US', {
    weekday: 'long', year: 'numeric', month: 'long', day: 'numeric'
  }),
  'iso': d.toISOString()
};
return formats[args.format] || formats.short;

Key points:

  • Access parameters via the args object
  • Return any JSON-serializable value
  • Use await for async operations
  • Full access to browser APIs (fetch, localStorage, etc.)

Python Tools

Python tools execute on the backend server. They can use any Python libraries installed on the server.

# Example: Calculate statistics
# Parameters: { numbers: array }

import json
import sys
import statistics

# Read args from stdin
args = json.loads(sys.stdin.read())
numbers = args['numbers']

result = {
    'mean': statistics.mean(numbers),
    'median': statistics.median(numbers),
    'stdev': statistics.stdev(numbers) if len(numbers) > 1 else 0
}

# Output JSON result
print(json.dumps(result))

Key points:

  • Read arguments from stdin as JSON
  • Print JSON result to stdout
  • 30-second timeout (configurable up to 60s)
  • Use any installed Python packages
  • Stderr is captured for debugging

HTTP Tools

HTTP tools call external REST APIs. Configure the endpoint and Vessel handles the request.

Configuration:

  • Endpoint — Full URL (e.g., https://api.example.com/data)
  • Method — GET or POST
  • Parameters — Sent as query params (GET) or JSON body (POST)

The tool returns the JSON response from the API.

Defining Parameters

Parameters tell the model what inputs your tool expects:

Field Description
Name Parameter identifier (e.g., query, count)
Type string, number, integer, boolean, array, object
Description Explains what this parameter is for
Required Whether the model must provide this parameter
Enum Optional list of allowed values

Built-in Templates

Vessel provides 8 starter templates to help you get started:

JavaScript:

  • API Request — Fetch data from REST APIs
  • JSON Transform — Filter and reshape JSON data
  • String Utilities — Text manipulation functions
  • Date Utilities — Date formatting and timezone conversion

Python:

  • API Request — HTTP requests with urllib
  • Data Analysis — Statistical calculations
  • Text Analysis — Word frequency and sentiment
  • Hash & Encode — MD5, SHA256, Base64 operations

Testing Tools

Before saving, use the Test panel:

  1. Enter sample parameter values
  2. Click Run Test
  3. View the result or error message
  4. Iterate until the tool works correctly

Enabling/Disabling Tools

  • Global toggle — Enable/disable all tools at once
  • Per-tool toggle — Enable/disable individual tools
  • Disabled tools won't be sent to the model

Security Considerations

  • JavaScript runs in the browser with your session's permissions
  • Python runs on the backend with server permissions
  • HTTP tools can call any URL — be careful with sensitive endpoints
  • Tools are stored locally in your browser (IndexedDB)

Programmatic Tool Creation

Tools are stored in localStorage. You can manage them programmatically:

// Tool definition structure
interface CustomTool {
  id: string;
  name: string;
  description: string;
  parameters: {
    type: 'object';
    properties: Record<string, {
      type: 'string' | 'number' | 'boolean' | 'array' | 'object';
      description: string;
      enum?: string[];
    }>;
    required: string[];
  };
  implementation: 'javascript' | 'python' | 'http';
  code?: string;        // For JS/Python
  endpoint?: string;    // For HTTP
  httpMethod?: 'GET' | 'POST';
  enabled: boolean;
  createdAt: number;
  updatedAt: number;
}

// Access via localStorage
const tools = JSON.parse(localStorage.getItem('customTools') || '[]');

Example: Weather Tool

Here's a complete example of a JavaScript tool that fetches weather:

Name: get_weather

Description: Get current weather for a city. Use this when the user asks about weather conditions.

Parameters:

Name Type Required Description
city string Yes City name (e.g., "London", "New York")
units string No Temperature units: "celsius" or "fahrenheit"

Code (JavaScript):

const city = encodeURIComponent(args.city);
const units = args.units === 'fahrenheit' ? 'imperial' : 'metric';

const response = await fetch(
  `https://api.openweathermap.org/data/2.5/weather?q=${city}&units=${units}&appid=YOUR_API_KEY`
);

if (!response.ok) {
  throw new Error(`Weather API error: ${response.status}`);
}

const data = await response.json();
return {
  city: data.name,
  temperature: data.main.temp,
  description: data.weather[0].description,
  humidity: data.main.humidity
};

Roadmap

Vessel is intentionally focused on being a clean, local-first UI for Ollama. The roadmap prioritizes usability, clarity, and low friction over feature breadth.

Core UX Improvements (Near-term)

These improve the existing experience without expanding scope.

  • Improve model browser & search
    • better filtering (size, tags, quantization, capabilities)
    • clearer metadata presentation
    • update detection for installed models
  • Custom tools system
    • JavaScript, Python, and HTTP tool creation
    • built-in templates and testing panel
  • System prompt management
    • prompt library with model-specific defaults
    • capability-based auto-selection
  • Custom model creation
    • embed system prompts into Ollama models
    • edit existing custom models
  • Keyboard-first workflows
    • model switching
    • prompt navigation
  • UX polish & stability
    • error handling
    • loading / offline states
    • small performance improvements

Local Ecosystem Quality-of-Life (Opt-in)

Still local-first, still focused — but easing onboarding and workflows.

  • Docker-based Ollama support (for systems without native Ollama installs)
  • Optional voice input/output (accessibility & convenience, not a core requirement)
  • Presets for common workflows (model + tool combinations, kept simple)

Experimental / Explicitly Optional

These are explorations, not promises. They are intentionally separated to avoid scope creep.

  • Image generation support (only if it can be cleanly isolated from the core UI)
  • Hugging Face integration (evaluated carefully to avoid bloating the local-first experience)

Non-Goals (By Design)

Vessel intentionally avoids becoming a platform.

  • Multi-user / account-based systems
  • Cloud sync or hosted services
  • Large plugin ecosystems
  • "Universal" support for every LLM runtime

If a feature meaningfully compromises simplicity, it likely doesn't belong in core Vessel.

Philosophy

Do one thing well. Keep the UI out of the way. Prefer clarity over configurability.


Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Issues and feature requests are tracked on GitHub: https://github.com/VikingOwl91/vessel/issues

  1. Fork the repository
  2. Create your feature branch (git checkout -b feature/amazing-feature)
  3. Commit your changes (git commit -m 'Add some amazing feature')
  4. Push to the branch (git push origin feature/amazing-feature)
  5. Open a Pull Request

License

Copyright (C) 2026 VikingOwl

This project is licensed under the GNU General Public License v3.0 - see the LICENSE file for details.


Made with Ollama and Svelte