The QCOS quantum SDK: Python, the command line and AI agents
The SoftQuantus quantum SDK is a set of versioned packages on PyPI that reach QCOS, the SoftQuantus quantum operating system. Write a program in Python or HiQ, run it from a notebook, a shell or an AI agent, and get back a result with the evidence to recheck it.
Every package speaks to the same REST API, so a job submitted from the CLI and one submitted from an agent leave the same sealed record.
- Python
- softqcos-sdk
- Shell
- softqcos CLI
- AI agents
- softqcos-mcp
The packages
What each package does
Install only what you need. Every package carries a version number on PyPI, so you decide when to upgrade.
| Package | What it does | Stage |
|---|---|---|
| softqcos-sdk | Python client for the QCOS API: list backends, submit jobs, wait for results, read artifacts and evidence | Available |
| softqcos | Command-line interface for the same calls, including login and key handling | Available |
| softqcos-mcp | MCP server that offers the QCOS runtime to AI agents as tools | Available |
| softquantus-verify | Open-source (MIT) verifier that recomputes an evidence seal offline | Available |
| quantumlock | Python client for QuantumLock licence validation | In production |
| TypeScript, Go and Rust clients | The same contract in other languages | Roadmap |
Results from QCOS today come from the CPU state-vector simulator, up to 24 qubits. Each result carries an execution_mode label.
Install
Four packages, one pip line
Create an API key on platform.softquantus.com first. The SDK reads it from api_key=, then QCOS_API_KEY, then softqcos login.
pip install softqcos-sdk softqcos softqcos-mcp softquantus-verify
export QCOS_API_KEY="your-api-key"Beyond Python
A quantum API, a language and an agent interface
The SDK is a thin layer over the QCOS REST API at api.softquantus.com. Any language that can send an HTTPS request with an X-API-Key header can use QCOS today.
HiQ is the SoftQuantus programming language for quantum computers, with four layers from objects to pulses. QCOS checks and compiles HiQ programs.
REST API
Circuits, algorithms, error correction and evidence verification.
HiQ
Objects, Script, Assembly and Pulse, checked and compiled by QCOS.
MCP
The same contract for AI agents, with the tools listed by the server.
Evidence
Every job sealed under a SHA-256 Merkle root, rechecked offline.
Questions
Quantum SDK questions
What is a quantum SDK?
A software development kit for writing quantum programs, sending them to a quantum computer or simulator and reading the results. The SoftQuantus quantum SDK is the set of QCOS packages on PyPI.
Which quantum SDK does SoftQuantus publish?
softqcos-sdk for Python, the softqcos CLI, the softqcos-mcp server for AI agents and the softquantus-verify evidence verifier. The quantumlock package validates QuantumLock licences, and the post-quantum SDK page covers signing.
Is there a quantum computing API without an SDK?
Yes. QCOS is a REST API at api.softquantus.com. The API page lists the routes and shows a full request with curl.
Can AI agents use the quantum SDK?
Yes, through softqcos-mcp, an MCP server that offers the QCOS runtime to agents as tools. See MCP integration.
Does the SDK run programs on quantum hardware?
Not yet. Programs run on the QCOS CPU state-vector simulator, up to 24 qubits. Quantum hardware is reached through Softquantus Cloud, which is in development.
Is the SDK open source?
The client packages are published on PyPI under SoftQuantus's licence. The verifier softquantus-verify is open source under MIT. QCOS source code is private.
Read next
More for developers
Run a first job in a few minutes
Create a key, install softqcos-sdk and submit a circuit to the simulator. The evidence of the run comes back with the result.