Simpy

SimPy gives you process-based discrete-event simulation in Python using generator functions and an event scheduling system. You model entities competing for shared resources over time, like customers waiting for servers, packets moving through networks, or parts flowing through manufacturing lines. The framework handles three resource types (Resource, Container, Store) with priority and preemptive variants, plus event composition with AllOf and AnyOf operators. It's built for queue analysis and capacity planning where things arrive at irregular intervals and wait for constrained resources. If your simulation runs on fixed time steps or processes don't share resources, this isn't the right tool.

skills.sh installs: 2.1K
GitHub stars: 56.6K
last updated: Aug 21, 2026

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Install

$ npx -y skills add k-dense-ai/scientific-agent-skills --skill simpy --agent claude-code

Installs into .claude/skills of the current project.

Files

SimPy

Scope

Use this skill for process-based discrete-event models where active entities yield events and contend for resources: queues, production systems, logistics, networks, service operations, inventory, and other event-driven systems.

SimPy supplies an event scheduler and modeling primitives. It does not choose a scientifically valid conceptual model, input distribution, warm-up, run length, replication count, estimand, or causal interpretation. Treat those as simulation-study methodology, not SimPy API behavior.

Current release and installation

Reviewed 2026-10-01 against current official documentation and the released source:

Latest stable: SimPy 4.1.2, released on PyPI 2026-05-24; source tag 4.1.2 points to commit f4381649.
Package metadata requires Python >=3.8 and classifies CPython 3.8-3.14 plus PyPy. SimPy has no runtime dependencies.
4.1.2 adds Python 3.13/3.14 support and modern-interpreter test fixes.
Upstream and this skill are MIT-licensed.

Create a reproducible environment:

SKILL.md on GitHub