MCP Tools & Schema

When the CrimsonMCPTools plugin is enabled, CrimsonInventory exposes six debug tools and a set of schema resources to MCP-aware clients (Claude Code, etc.). Tools query a running PIE session; schema resources are static class/pattern docs that work offline.

Inspection tools

Tool	Args	What it dumps
`crimson.inventory.list_items`	`ActorName` (optional, defaults to first player pawn)	Every entry on the actor's manager component: EntryId, slot, grid (X,Y), rotation, layout group, locked, stacks, definition, integer stat tags.
`crimson.inventory.list_constraints`	`ActorName` (optional)	Runtime constraint stack (active `UCrimsonInventoryConstraint` subobjects) + every int/float tag-stack cap with current/max values. The 'why won't this item add?' tool.
`crimson.inventory.inspect_layout`	`ActorName` (optional)	Layout asset class + path, capacity hint, rotation/stacking support, runtime cache stats (tracked entries, slot lookups, grid size + occupied/free cells), per-`LayoutGroupId` entry counts.
`crimson.inventory.inspect_container`	`ActorName` (REQUIRED - chest's outliner label)	Chest's `ContainerTag`, `Scope`, `DefaultLayout`, and a description of where the storage actually lives per scope. Flags missing tags for non-Shared scopes.
`crimson.inventory.list_instances`	(none)	Every active `ACrimsonInstancedInventoryActor` (PerParty / PerDungeonInstance) with its key, viewer count, and entry count. Server / standalone PIE only.
`crimson.inventory.list_routing`	`PlayerControllerName` (optional)	All `UCrimsonInventoryManagerComponent`s hosted on a PC's routing component - the personal (PerPlayer) container storage. Shows tag, layout class, and entry count per container.

Debugging a failed chest open

1. inspect_container <ChestLabel> - verify Scope and ContainerTag are set correctly.
2. For PerPlayer: list_routing <PCLabel> - confirm the personal container was created.
3. For PerParty / PerDungeonInstance: list_instances - confirm an instance actor exists and that the PC is in the viewer set.
4. list_constraints <Inv> - check if a constraint vetoed the open.

Schema resources

Class and pattern docs generated from the live UClass metadata + handwritten markdown. Use these for offline lookups; they don't need an active PIE session.

URI	Content
`crimson://schema/inventory/item-definition`	`UCrimsonInventoryItemDefinition` class doc
`crimson://schema/inventory/item-fragments`	All `UCrimsonInventoryItemFragment` subclasses with properties
`crimson://schema/inventory/state-fragments`	All `UCrimsonInventoryStateFragment` subclasses (Durability, Lifetime, etc.)
`crimson://schema/inventory/footprint-fragment`	`UCrimsonInventoryItemFragment_Footprint` class doc
`crimson://schema/inventory/layouts`	All `UCrimsonInventoryLayout` subclasses (FlatSlot, Grid, Weight)
`crimson://schema/inventory/constraints`	All `UCrimsonInventoryConstraint` subclasses (Slot, IntTag, FloatTag, TypeFilter, GridCellRule, StackLimit, CustomRule)
`crimson://schema/inventory/routing-component`	`UCrimsonInventoryRoutingComponent` class doc (RPCs, virtuals, save API)
`crimson://schema/inventory/container-actor`	`ACrimsonContainerActorBase` class doc (Scope, ContainerTag, OnScopedInstanceCreated)

Pattern guides

URI	Walkthrough
`crimson://patterns/inventory/consumable`	Health-potion-style stackable consumable + GAS consume ability
`crimson://patterns/inventory/weapon`	Unique weapon with Footprint dimensions + Equipment integration
`crimson://patterns/inventory/container-actor`	World chest: all four scopes, OnScopedInstanceCreated, per-scope save
`crimson://patterns/inventory/scoped-chest`	Deep dive: PerPlayer / PerParty / PerDungeonInstance with ResolvePartyKey override + lifecycle (viewer add/remove, instance destroy)
`crimson://patterns/inventory/bag-extension`	Runtime cap bumps via `ModifyIntConstraintValue` + rich-rule variant with a `_TypeFilter` constraint

How to invoke

From an MCP-aware client connected to your Unreal Editor, call the tool by name with the documented args. Schema resources are fetched as text/markdown by URI. The CrimsonMCPTools plugin must be enabled in the same project for any of this to be reachable.