From 3e73fb9ea2dc8c62e324c7329fc0d70dd668fdb5 Mon Sep 17 00:00:00 2001
From: starlight <ss14-Starlight@outlook.com>
Date: Mon, 1 Jun 2026 02:23:15 +0200
Subject: [PATCH] Make HTN planning budget configurable via cvar

---
 Content.Server/NPC/HTN/HTNSystem.cs                | 14 +++++++++++++-
 .../_Starlight/NPC/HTN/AdjustableJobQueue.cs       | 13 +++++++++++++
 Content.Shared/CCVar/CCVars.NPC.cs                 |  9 +++++++++
 3 files changed, 35 insertions(+), 1 deletion(-)
 create mode 100644 Content.Server/_Starlight/NPC/HTN/AdjustableJobQueue.cs

diff --git a/Content.Server/NPC/HTN/HTNSystem.cs b/Content.Server/NPC/HTN/HTNSystem.cs
index 7bfe43299865..18fe751f849c 100644
--- a/Content.Server/NPC/HTN/HTNSystem.cs
+++ b/Content.Server/NPC/HTN/HTNSystem.cs
@@ -2,6 +2,11 @@
 using System.Text;
 using System.Threading;
 using Content.Server.Administration.Managers;
+// Starlight start
+using Content.Server._Starlight.NPC.HTN;
+using Content.Shared.CCVar;
+using Robust.Shared.Configuration;
+// Starlight end
 using Robust.Shared.CPUJob.JobQueues;
 using Robust.Shared.CPUJob.JobQueues.Queues;
 using Content.Server.NPC.HTN.PrimitiveTasks;
@@ -22,8 +27,11 @@ public sealed class HTNSystem : EntitySystem
     [Dependency] private readonly IPrototypeManager _prototypeManager = default!;
     [Dependency] private readonly NPCSystem _npc = default!;
     [Dependency] private readonly NPCUtilitySystem _utility = default!;
+    [Dependency] private readonly IConfigurationManager _cfg = default!; // Starlight
 
-    private readonly JobQueue _planQueue = new(0.004);
+    // Starlight start - HTN plan budget is cvar-driven (npc.htn_plan_budget) instead of a hardcoded 0.004
+    private readonly AdjustableJobQueue _planQueue = new(0.004);
+    // Starlight end
 
     private readonly HashSet<ICommonSession> _subscribers = new();
 
@@ -40,6 +48,10 @@ public override void Initialize()
         SubscribeNetworkEvent<RequestHTNMessage>(OnHTNMessage);
         SubscribeLocalEvent<PrototypesReloadedEventArgs>(OnPrototypeLoad);
         OnLoad();
+
+        // Starlight
+        Subs.CVar(_cfg, CCVars.NPCHTNPlanBudget, value => _planQueue.SetMaxTime(value), true);
+        // Starlight end
     }
 
     private void OnHTNMessage(RequestHTNMessage msg, EntitySessionEventArgs args)
diff --git a/Content.Server/_Starlight/NPC/HTN/AdjustableJobQueue.cs b/Content.Server/_Starlight/NPC/HTN/AdjustableJobQueue.cs
new file mode 100644
index 000000000000..af44733cc20d
--- /dev/null
+++ b/Content.Server/_Starlight/NPC/HTN/AdjustableJobQueue.cs
@@ -0,0 +1,13 @@
+using Robust.Shared.CPUJob.JobQueues.Queues;
+
+namespace Content.Server._Starlight.NPC.HTN;
+
+public sealed class AdjustableJobQueue(double maxTime) : JobQueue
+{
+    private double _maxTime = maxTime;
+
+    public override double MaxTime => _maxTime;
+
+    public void SetMaxTime(double maxTime)
+        => _maxTime = maxTime;
+}
diff --git a/Content.Shared/CCVar/CCVars.NPC.cs b/Content.Shared/CCVar/CCVars.NPC.cs
index f0d5520195d0..71dde6fe2a9d 100644
--- a/Content.Shared/CCVar/CCVars.NPC.cs
+++ b/Content.Shared/CCVar/CCVars.NPC.cs
@@ -13,4 +13,13 @@ public sealed partial class CCVars
     ///     Should NPCs pathfind when steering. For debug purposes.
     /// </summary>
     public static readonly CVarDef<bool> NPCPathfinding = CVarDef.Create("npc.pathfinding", true);
+
+    // Starlight start
+    /// <summary>
+    ///     Per-tick wall-clock budget (seconds) the HTN planner is allowed to spend running plan jobs.
+    ///     Lower it to cap NPC planning cost under load. Was a hardcoded 0.004 (4ms) in HTNSystem.
+    /// </summary>
+    public static readonly CVarDef<float> NPCHTNPlanBudget =
+        CVarDef.Create("npc.htn_plan_budget", 0.004f, CVar.SERVERONLY);
+    // Starlight end
 }