OPEN SWISS LANGUAGE MODEL

How can I help?

Ask a question, develop an idea, or let Apertus reason through a problem and use tools.

Apertus can make mistakes. Verify important information. GPU use counts against your ZeroGPU quota.

Language model

Choose the chat model for this browser workspace.

ThinkingShow the reasoning trace.

Instructions

System prompt

Tools

Tool useLet the model select enabled tools when useful.

Tool-use policy

This policy is added to the system prompt only while Tool Use is active.

Remote MCP serversDiscover tools from the configured remote MCP servers RetrievalSearch the browser workspace's global document embeddings Current timeIANA timezones CalculatorSafe arithmetic expressions

Tool descriptions

Retrieval Current time Calculator

Max tool rounds 3

Planning

PlanningLoop 0 creates the plan; the final loop produces the answer.

Min loop 2 Max loop 3

Generation

Maximum new tokens 2048 Temperature 0.70

Top-p Top-k Min-p Repetition penalty

Seed Randomize

Context

History messages Input tokens

Retrieval tool

Files and embeddings are saved only in this browser workspace and are available in every conversation. The server creates embeddings transiently and does not retain document data.

Embedding model

Embedding device

CPUDefault · no ZeroGPU queue GPUFaster · uses ZeroGPU quota

Chunk size Overlap

Retrieved chunks 4

Document embeddings

Add document

Conversation data

Show raw tracesKeep complete traces stored, but control whether they appear below answers. Show feedbackDisplay local thumbs-up and thumbs-down controls below model answers.

The complete workspace stays in this browser. JSON export and import include chats, settings, documents and embeddings.

Hugging Face datasets

The SFT dataset contains positively rated answers. Feedback labels contain every rated answer with a +1 or −1 label for reward modelling or later alignment preparation; they are not DPO preference pairs. Both use the complete local history.

Remote MCP servers

Remote MCP servers are discovered when Tools is enabled. The JSON follows the standard mcpServers format. Headers are stored in this browser and included in workspace exports.

Server configuration

Example: https://mcp.opencaselaw.ch provides searchable Swiss court decisions. Use an empty headers object when no key is required.

Local MCP endpoint

The endpoint follows the current app domain, including a configured custom domain.