A sound starting skeleton for driving STK from an agent, but three tools, no licence and an unproven HTTP launcher make it a code sample rather than something to point an analyst at. We rate it 2.7 out of 5.

How much does STK-MCP cost?

The server is free to download but has no licence; it needs a paid, licensed Ansys STK 12 Desktop or STK Engine installation (prices not published).

What are the downsides of STK-MCP?

Only 3 tools; no TLE, sensors, coverage or link analysis; no satellite creation on Linux STK Engine; no licence file, so reuse is all rights reserved; hTTP launcher looks broken against MCP SDK 1.14.0; issues unanswered.

How much does STK-MCP cost for a team or in production?

The server costs nothing; the STK Desktop or STK Engine licence is the real bill, quoted by Ansys sales and not published. Each MCP session holds one STK instance behind a global lock, so parallel agents need parallel licences.

Is STK-MCP safe for company data?

Runs locally and drives a local STK instance; nothing is sent to a third party except what reaches your model provider. The HTTP endpoint has no authentication, so it must stay on localhost.

STK-MCP MCP server review (updated)

What is STK-MCP?

STK-MCP, from the GitHub user alti3, connects an MCP client to Ansys Systems Tool Kit (STK), the commercial mission-analysis software used to model satellites, ground stations and their lines of sight. It starts and manages its own STK 12 instance, either STK Desktop on Windows or STK Engine on Windows or Linux, and exposes 3 tools and 5 read-only resources: set up a scenario, create a facility or place, create a satellite from apogee, perigee, RAAN and inclination, list objects, and compute access intervals and latitude-longitude-altitude ephemeris.

It is a young, single-developer project: 43 GitHub stars, 10 forks, no tagged releases (version 0.2.0 in pyproject.toml) and a last commit on 19 January 2026. The repository carries no licence file. It needs a licensed STK installation and the agi.stk12 Python wheel that ships with it; Ansys does not publish STK prices.

How to install STK-MCP

git clone https://github.com/alti3/stk-mcp && cd stk-mcp && uv add ./agi.stk12-12.10.0-py3-none-any.whl && uv sync

Is STK-MCP worth it?

STK-MCP covers the first ten minutes of an STK tutorial and stops. You can create a scenario with a time window (48 hours from 20 January 2020 by default), drop a ground facility at a latitude and longitude, add a satellite on a two-body orbit from apogee, perigee, RAAN and inclination, then ask for access intervals between the two or the satellite's ephemeris at 60-second steps. That is enough to answer "when does this orbit see Boulder", and nothing more: no TLE or SGP4 import, no sensors, no constraints, no coverage, no link budgets, none of the analysis people buy STK for.

The platform split is narrower than the README's headline suggests. Satellite creation imports its STK types only when the operating system is Windows, and the README's own table marks create_satellite as unavailable on STK Engine for Linux, so a headless Linux server can build scenarios and ground sites but not satellites. macOS is not supported at all. Everything is written against the agi.stk12 API and pinned to a 12.10 wheel, while Ansys's PySTK compatibility table already lists STK 13.0 and 13.1; the README says nothing about STK 13.

The catch: we are not confident the server, as committed, answers an MCP client. In our reading of cli.py, the run command hands the FastMCP object directly to uvicorn and assigns a lifespan afterwards; in the locked MCP Python SDK 1.14.0, FastMCP is not itself a web app (that is what sse_app() and streamable_http_app() return). Issue 2, a start-up error report from May 2025, and issue 5 have no replies. It binds to 127.0.0.1:8765 by default with no authentication, so changing the host to share it would hand any caller control of a licensed STK session.

The missing licence matters for anyone at a company. With no LICENSE file and no licence in pyproject.toml, the default is all rights reserved: you can read the code on GitHub, but copying or modifying it inside an aerospace programme is legally unclear until the author adds one.

Our take: STK's own Python API, PySTK, is MIT-licensed and documented; a team that already pays for STK will get further writing its own small server on that, using this repository as a 16-commit map of where the sharp edges are.

Where it earns its place

A mission analyst at a small-satellite start-up with an STK 12 Desktop seat
Ask when a proposed orbit passes over the company's ground station
setup_scenario for the planned window, create_location for the station, create_satellite from apogee, perigee, inclination and RAAN, then read resource://stk/analysis/access/Satellite/<name>/Facility/<site>. Two-body only, so check results against a proper propagator before quoting them.
A software engineer on an aerospace tools team
Prototype an internal agent that drives STK Engine
Read the stk_logic modules for how STK is started, locked and retried, then rebuild on PySTK under your own licence. Saves a day of discovery; shipping this code itself is unsafe until it has a licence.

Before you commit

Setup: git clone, uv venv, uv add the agi.stk12 wheel from your STK install's CodeSamples folder, uv sync, then uv run -m stk_mcp.cli run --mode engine (or --mode desktop on Windows). Python 3.12+. Listens on http://127.0.0.1:8765; documented only for the MCP Inspector.
Integrations: 3 tools (setup_scenario, create_location, create_satellite) and 5 resources: all objects, objects by type, health, access between two objects, and LLA ephemeris. All tools write to the STK scenario; resources only read.
Data and privacy: Runs locally and drives a local STK instance; nothing is sent to a third party except what reaches your model provider. The HTTP endpoint has no authentication, so it must stay on localhost.
Cost at scale: The server costs nothing; the STK Desktop or STK Engine licence is the real bill, quoted by Ansys sales and not published. Each MCP session holds one STK instance behind a global lock, so parallel agents need parallel licences.
Limits: Two-body propagation only; no TLE, sensors, coverage or reports beyond LLA. STK 12 API only. Satellite creation Windows-only. One developer, no releases, two unanswered issues.

What’s good

Supports both STK Desktop and STK Engine
Access intervals and LLA ephemeris as MCP resources
Serialises STK calls with a lock and retries flaky Connect commands
Input checks on apogee, inclination and RAAN

What’s not

Only 3 tools; no TLE, sensors, coverage or link analysis
No satellite creation on Linux STK Engine
HTTP launcher looks broken against MCP SDK 1.14.0; issues unanswered

Best for

Engineers who already hold an STK 12 licence and want a starting point for their own agent integration, not a finished tool.

STK-MCP: common questions

Is STK-MCP worth it?: A sound starting skeleton for driving STK from an agent, but three tools, no licence and an unproven HTTP launcher make it a code sample rather than something to point an analyst at. We rate it 2.7 out of 5.
How much does STK-MCP cost?: The server is free to download but has no licence; it needs a paid, licensed Ansys STK 12 Desktop or STK Engine installation (prices not published).
What are the downsides of STK-MCP?: Only 3 tools; no TLE, sensors, coverage or link analysis; no satellite creation on Linux STK Engine; no licence file, so reuse is all rights reserved; hTTP launcher looks broken against MCP SDK 1.14.0; issues unanswered.
Who is STK-MCP best for?: Engineers who already hold an STK 12 licence and want a starting point for their own agent integration, not a finished tool.
How much does STK-MCP cost for a team or in production?: The server costs nothing; the STK Desktop or STK Engine licence is the real bill, quoted by Ansys sales and not published. Each MCP session holds one STK instance behind a global lock, so parallel agents need parallel licences.
Is STK-MCP safe for company data?: Runs locally and drives a local STK instance; nothing is sent to a third party except what reaches your model provider. The HTTP endpoint has no authentication, so it must stay on localhost.

Answers checked Nov 9, 2026.