feat(mcp): add guided construction workflows

packages/mcp/src/tools/place-item.test.ts

@@ -2,7 +2,7 @@ import { beforeEach, describe, expect, test } from 'bun:test'
 import { Client } from '@modelcontextprotocol/sdk/client/index.js'
 import { InMemoryTransport } from '@modelcontextprotocol/sdk/inMemory.js'
 import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'
-import { WallNode } from '@pascal-app/core/schema'
+import { SlabNode, WallNode } from '@pascal-app/core/schema'
 import { SceneBridge } from '../bridge/scene-bridge'
 import { registerPlaceItem } from './place-item'
 
@@ -29,7 +29,7 @@ describe('place_item', () => {
     const result = await client.callTool({
       name: 'place_item',
       arguments: {
-        catalogItemId: 'chair:basic',
+        catalogItemId: 'shelf',
         targetNodeId: wall.id,
         position: [5, 0, 0],
       },
@@ -37,20 +37,48 @@ describe('place_item', () => {
     expect(result.isError).toBeFalsy()
     const parsed = JSON.parse((result.content as Array<{ type: string; text: string }>)[0]!.text)
     expect(parsed.itemId).toMatch(/^item_/)
-    expect(parsed.status).toBe('catalog_unavailable')
+    expect(parsed.status).toBe('ok')
     const item = bridge.getNode(parsed.itemId)
     expect(item).not.toBeNull()
     // Midpoint of a [0..10] wall at x=5 → wallT = 0.5.
     expect((item as { wallT?: number }).wallT).toBeCloseTo(0.5, 3)
+    expect((item as { position: [number, number, number] }).position[0]).toBeCloseTo(5, 3)
   })
 
-  test('rejects placement on a level', async () => {
+  test('places a floor item through a slab target but parents it to the level for rendering', async () => {
     const level = Object.values(bridge.getNodes()).find((n) => n.type === 'level')!
+    const slab = SlabNode.parse({
+      polygon: [
+        [0, 0],
+        [4, 0],
+        [4, 4],
+        [0, 4],
+      ],
+    })
+    bridge.createNode(slab, level.id)
+
+    const result = await client.callTool({
+      name: 'place_item',
+      arguments: {
+        catalogItemId: 'sofa',
+        targetNodeId: slab.id,
+        position: [2, 0, 2],
+      },
+    })
+    expect(result.isError).toBeFalsy()
+    const parsed = JSON.parse((result.content as Array<{ type: string; text: string }>)[0]!.text)
+    const item = bridge.getNode(parsed.itemId)
+    expect(item?.parentId).toBe(level.id)
+    expect(bridge.validateScene().valid).toBe(true)
+  })
+
+  test('rejects placement on an unsupported node', async () => {
+    const building = Object.values(bridge.getNodes()).find((n) => n.type === 'building')!
     const result = await client.callTool({
       name: 'place_item',
       arguments: {
         catalogItemId: 'foo',
-        targetNodeId: level.id,
+        targetNodeId: building.id,
         position: [0, 0, 0],
       },
     })