simulate-network-latency - Skill Definition

1. Overview

Injects controlled network degradation (packet loss, jitter, high latency) to stress-test netcode rollback and prediction algorithms. Validates the robustness of client-server synchronization under extreme conditions, identifying desynchronization points that would break multiplayer gameplay. Output: structured network_test.md with failure categorization and severity mapping.

2. When to Use

Use when:

• You have multiplayer netcode and want to stress-test rollback and prediction under degraded conditions.
• Players report desyncs, hit registration issues, or movement stutter that may be network-related.
• Validating rejoin/reconnection behavior after transient high latency or packet loss.

Do not use when:

• The game is single-player with no netcode — this skill targets multiplayer synchronization.
• Basic connectivity isn't established yet — fix the happy path first.

3. Triggers & Red Flags

• Triggers: simulate-network-latency, network test, packet loss, latency test, rollback, prediction, netcode, network simulation, lag testing.
• Red Flags:
  • Critical Desynchronization (Desync): Observed divergence in game state between clients that cannot be reconciled by existing mechanisms.
  • Prediction/Reconciliation Failure: Client prediction consistently fails to align with server truth under moderate conditions.
  • Unrecoverable Connection Drop: Total failure to handle rejoin or reconnection attempts after transient high latency/loss scenarios.

3. Core Pattern

1. Condition Profiling — Define a matrix of test scenarios ranging from LAN to Worst-case (Satellite) conditions, specifying Ping, Packet Loss, and Jitter for each scenario.
2. Stress Testing Execution — Monitor key metrics including Player Movement (prediction accuracy), Combat Hits (registration precision), State Sync (consistency), and Resilience.
3. Failure Categorization & Severity Mapping — Classify failures by severity: Low (negligible), Medium (noticeable), High (degrading experience), or Critical (unplayable/desync).
4. Root Cause Analysis (RCA) — For high-severity failures, identify technical causes (e.g., insufficient prediction windows or lack of validation).
5. Specification Export — Write the finalized analysis into {TARGET_FOLDER}/docs/network_test.md.

4. Intercepts & Guards

• [Desync Detection Intercept]: If two clients show divergent game states: "I've detected a critical state desynchronization between Client A and Client B at [Time/Event]. This is a 'Critical' failure that must be resolved before further testing."
• [Prediction Failure Intercept]: If client prediction fails to reconcile with server truth: "The rollback mechanism failed to reconcile the position of [Entity] during [Condition]. This indicates an insufficient prediction window. Should we increase the buffer or refine reconciliation logic?"

5. Strategic Imperative

Treat "Network Unreliability" as the baseline reality. Never assume a stable connection; if high-severity failures occur under extreme conditions, they MUST be addressed before multiplayer release is considered viable.