Why are BTreeMaps preferred over HashMaps in Nethercore?

HashMaps have non-deterministic iteration orders which vary between runs, leading to desyncs. BTreeMaps provide a stable, sorted order required for deterministic game state.

What is a sync test in Nethercore?

A sync test runs two identical game instances simultaneously and compares frame-by-frame checksums to ensure they stay in perfect synchronization without diverging.

Can I test specific game levels without playing through the whole game?

Yes, the skill supports debug actions that allow you to skip directly to specific frames or levels using structured TOML configurations for efficient scenario testing.

How does this skill help with game desyncs?

It identifies common non-deterministic patterns—such as system time usage, uninitialized memory, or floating-point math—and provides debugging workflows using logs and checksums.

Does it support regression testing for game updates?

Yes, you can record a 'known-good' build into a replay file and play it back against a new build to verify that game outcomes and logic remain identical.

Nethercore Game Testing

Name: Nethercore Game Testing
Author: nethercore-systems

bynethercore-systems

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Game Development

Automates determinism checks and regression testing for Nethercore engine games to ensure consistent multiplayer synchronization.

Nethercore Testing is a specialized Claude Code skill designed to help developers maintain game state integrity and synchronization. It provides comprehensive tools for running frame-by-frame sync tests, recording and replaying sessions for regression analysis, and identifying common causes of desyncs like non-deterministic RNG or floating-point errors. By integrating specific determinism rules and debug actions, this skill allows developers to efficiently simulate edge cases and validate game logic across different builds, ensuring a stable experience for multiplayer and rollback-based gameplay.

Key Features

01Frame-by-frame sync testing with automated checksum comparison

02Session recording and replay for robust regression validation

03Automated identification of common desync causes like non-deterministic RNG

04Debug action support for skipping directly to specific game states or levels

05Enforcement of determinism rules for Rust-based game logic and state

061 GitHub stars

Use Cases

01Detecting synchronization issues between local game instances during development

02Validating that new code changes do not break existing gameplay replays

03Debugging complex state desyncs by isolating forbidden non-deterministic patterns

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add nethercore-systems/nethercore-ai-plugins testing

For use in Claude.ai and ChatGPT

Download Skill