fix(survival): sandbox creative kit no longer fills the backpack — mining works again (#677)

TODO.md

@@ -6971,6 +6971,20 @@ is **pre-approved** (keys in `tools/ai-assets/.env`, run via `uv`).
 
 ---
 
+## ✅ Done (2026-08-03): Sandbox mining unblocked — creative kit materials go to the cargo hold (#677)
+
+In Sandbox (and Creative with the kit ticked) a fresh player could not mine most blocks: the forced
+creative starter kit (23 stacks) plus the protected starter gear filled all 24 backpack slots, and since
+#600 `BreakBlockAt` refuses any break whose drops don't fit (`@inventory_full`) — on foot the pool counts
+the backpack only. Neither side ever gated mining on `GameMode.Creative`; it was pure inventory pressure.
+
+- **`GameServer.ApplyCreativeGrants`**: kit *tools* (titanium_drill, advanced_scanner) go to the backpack;
+  every *material* stack goes straight to the active ship's cargo hold (starter hold: 48 slots). Leftovers
+  are logged, never spilled back into the backpack — free backpack slots ARE the fix. The ship is saved
+  with the one-time flag so the hold's kit survives a crash before autosave.
+- Tests (`CreativeModeTests`): kit lands in cargo + backpack keeps ≥5 free slots; regression "fresh
+  creative player mines mud on foot"; persistence test moved to cargo counts.
+
 ## ✅ Done (2026-08-03): flora reads varied, not stamped — per-plant size/placement/tint variation (#675)
 
 All flora of a species rendered identically: solid flora (cactus/crystal/mushroom/…) stamped the same

src/BlocksBeyondTheStars.GameServer/GameServer.cs

@@ -2543,7 +2543,8 @@ private PlayerState CreateNewPlayer(string name)
 
     /// <summary>A curated "Creative" starter set (singleplayer): a couple of better tools + generous stacks of
     /// the key materials/ores/components so you can build right away. Survival mechanics still apply, so this is a
-    /// head start, not infinite resources. Unknown keys are skipped. (Inventory + ship cargo absorb the stacks.)</summary>
+    /// head start, not infinite resources. Unknown keys are skipped. (Tools go to the backpack; the material
+    /// stacks go to the ship's cargo hold so the backpack keeps free slots for mining — #677.)</summary>
     private static readonly (string Item, int Count)[] CreativeKit =
     {
         ("titanium_drill", 1), ("advanced_scanner", 1),
@@ -2598,18 +2599,41 @@ private void ApplyCreativeGrants(PlayerSession session)
 
         if (_meta.CreativeStarterKit && !_meta.CreativeKitGranted)
         {
-            var pool = new MaterialPool(_content, p, _ship);
+            // Only the kit's TOOLS go into the backpack; the material stacks land in the ship's cargo hold.
+            // The backpack has 24 slots and the starter gear already occupies five — stuffing the ~21 material
+            // stacks in there left it 24/24 full, and a full backpack refuses every on-foot mine since #600
+            // ("inventory full" on each swing), which players read as "mining is broken in Sandbox" (#677).
+            // The starter hold (48 slots) absorbs the whole kit; leftovers are dropped with a log rather than
+            // spilled back into the backpack, because free backpack slots ARE the fix.
+            int overflow = 0;
             foreach (var (item, count) in CreativeKit)
             {
-                if (_content.GetItem(item) is not null)
+                if (_content.GetItem(item) is not { } idef)
                 {
-                    pool.Add(item, count);
+                    continue;
+                }
+
+                int maxStack = _content.MaxStackOf(item);
+                if (idef.Category == ItemCategory.Tool)
+                {
+                    int left = p.Inventory.Add(item, count, maxStack);
+                    overflow += left > 0 ? _ship.Cargo.Add(item, left, maxStack) : 0;
+                }
+                else
+                {
+                    overflow += _ship.Cargo.Add(item, count, maxStack);
                 }
             }
 
+            if (overflow > 0)
+            {
+                _log.Warn($"Creative kit: {overflow} item(s) did not fit the cargo hold and were dropped.");
+            }
+
             _meta.CreativeKitGranted = true;
             _repo.SaveMetadata(_meta);
             _repo.SavePlayer(p); // persist the granted kit so a reload keeps it (and the one-time flag holds)
+            _repo.SaveShip(ShipSaveKey(p.PlayerId), _ship); // the kit lives in the hold now — persist it with the flag
             SendInventory(session);
         }
     }

tests/BlocksBeyondTheStars.Tests/CreativeModeTests.cs

@@ -6,6 +6,7 @@
 using BlocksBeyondTheStars.Persistence;
 using BlocksBeyondTheStars.Shared.Configuration;
 using BlocksBeyondTheStars.Shared.Content;
+using BlocksBeyondTheStars.Shared.Geometry;
 using Xunit;
 using SvGameServer = BlocksBeyondTheStars.GameServer.GameServer;
 
@@ -24,7 +25,7 @@ public CreativeModeTests()
         _content = ContentLoader.LoadFromDirectory(TestPaths.DataDir());
     }
 
-    private SvGameServer Start(string name, out SqliteWorldRepository repo, bool creative)
+    private SvGameServer Start(string name, out SqliteWorldRepository repo, bool creative, bool placeShip = true)
     {
         repo = new SqliteWorldRepository(new SaveGamePaths(_root, name));
         var st = new LoopbackServerTransport(new LoopbackLink());
@@ -33,7 +34,7 @@ private SvGameServer Start(string name, out SqliteWorldRepository repo, bool cre
             WorldName = name,
             Seed = 1,
             AutoSaveIntervalMinutes = 9999,
-            PlaceStarterShip = true,
+            PlaceStarterShip = placeShip,
             CreativeUnlockAllBlueprints = creative,
             CreativeStartAllShips = creative,
             CreativeStarterKit = creative,
@@ -62,8 +63,37 @@ public void CreativeWorld_UnlocksAllBlueprints_OwnsAllShips_AndGrantsKit()
             Assert.Contains("scout", types);
             Assert.Contains("corvette", types);
 
-            // The curated kit was granted (a generous stack of a key material reached the inventory).
-            Assert.True(p.State.Inventory.CountOf("iron_ore") > 0, "the creative kit should grant materials");
+            // The curated kit was granted: material stacks land in the ship's cargo hold, NOT the backpack —
+            // a backpack stuffed full of kit stacks refused every on-foot mine ("inventory full", #677).
+            var starter = server.OwnedShips.Values.First(s => s.ShipType == "starter");
+            Assert.True(starter.Cargo.CountOf("iron_ore") > 0, "the creative kit materials should reach the cargo hold");
+            Assert.Equal(0, p.State.Inventory.CountOf("iron_ore"));
+
+            // The kit's tools DO go to the backpack, and the backpack keeps room for mining drops.
+            Assert.Equal(1, p.State.Inventory.CountOf("titanium_drill"));
+            int freeSlots = p.State.Inventory.Slots.Count(s => s is null || s.IsEmpty);
+            Assert.True(freeSlots >= 5, $"the backpack must keep free slots for mining drops, had {freeSlots}");
+        }
+    }
+
+    [Fact]
+    public void CreativeKit_LeavesRoomToMine_FreshPlayerMinesTerrainOnFoot()
+    {
+        // Regression for #677: the forced Sandbox kit used to fill all 24 backpack slots, and a full
+        // backpack refuses every break since #600 — a fresh Sandbox player could not mine anything.
+        var server = Start("sandboxmine", out var repo, creative: true, placeShip: false);
+        using (repo)
+        {
+            var p = server.AddLocalPlayer("Host");
+            p.State.AboardShip = false; // on foot: drops must fit the backpack alone (cargo doesn't count)
+            p.State.Position = new Vector3f(0.5f, 66f, 0.5f); // basic_drill is starter slot 0
+            var pos = new Vector3i(0, 64, 0);
+            server.World.SetBlock(pos, _content.GetBlock("mud")!.NumericId); // soft: one basic-drill hit
+
+            server.MineBlockOnce("Host", pos.X, pos.Y, pos.Z);
+
+            Assert.True(server.World.GetBlock(pos).IsAir, "a fresh creative/sandbox player must be able to mine terrain (#677)");
+            Assert.True(p.State.Inventory.CountOf("mud") > 0, "the mined drop should land in the backpack");
         }
     }
 
@@ -93,7 +123,7 @@ public void CreativeOptions_PersistAcrossRestart_AndKitIsGrantedOnce()
             using (repo1)
             {
                 var p = s1.AddLocalPlayer("Host");
-                ironAfterFirst = p.State.Inventory.CountOf("iron_ore");
+                ironAfterFirst = s1.OwnedShips.Values.First(s => s.ShipType == "starter").Cargo.CountOf("iron_ore");
                 Assert.True(ironAfterFirst > 0);
                 repo1.Flush();
             }
@@ -106,7 +136,8 @@ public void CreativeOptions_PersistAcrossRestart_AndKitIsGrantedOnce()
             var p = s2.AddLocalPlayer("Host");
             Assert.Equal(_content.Blueprints.Count, p.State.UnlockedBlueprints.Count); // still all unlocked
             Assert.Contains("corvette", s2.OwnedShips.Values.Select(s => s.ShipType)); // still owns all ships
-            Assert.Equal(ironAfterFirst, p.State.Inventory.CountOf("iron_ore"));       // kit NOT granted again
+            int ironAfterReload = s2.OwnedShips.Values.First(s => s.ShipType == "starter").Cargo.CountOf("iron_ore");
+            Assert.Equal(ironAfterFirst, ironAfterReload);                             // kit NOT granted again
         }
     }