docs(mcp): add README, examples, and changelog

- README.md: install/quick start; configs for Claude Desktop, Claude
  Code, and Cursor; programmatic usage; tables covering all 21 tools,
  4 resources, and 3 prompts; limitations; development commands.
- CHANGELOG.md: 0.1.0 entry in Keep a Changelog format.
- examples/generate-apartment.md: prose transcript using from_brief
  to build an 80 m² 2-bed apartment, showing apply_patch, set_zone,
  cut_opening, validate_scene.
- examples/renovate-from-photos.md: prose transcript using the vision
  tools + renovation_from_photos prompt.
- examples/embed-in-agent.ts: compilable TypeScript showing
  programmatic usage via InMemoryTransport.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
Adrian Perez
2026-04-18 17:51:37 +02:00
co-authored by Claude Opus 4.7
parent 441e97b2b6
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# Changelog
All notable changes to `@pascal-app/mcp` will be documented in this file.
The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
## [0.1.0] - 2026-04-18
### Added
- Initial release.
- `SceneBridge` headless adapter for `@pascal-app/core` with RAF polyfill so
the Zustand store and Zundo temporal middleware run cleanly in Node.
- 19 MCP tools covering scene querying (`get_scene`, `get_node`,
`describe_node`, `find_nodes`, `measure`), mutation (`apply_patch`,
`create_level`, `create_wall`, `place_item`, `cut_opening`, `set_zone`,
`duplicate_level`, `delete_node`), undo/redo (`undo`, `redo`), export
(`export_json`, `export_glb`), validation (`validate_scene`,
`check_collisions`), plus 2 vision tools (`analyze_floorplan_image`,
`analyze_room_photo`) backed by MCP sampling.
- 4 MCP resources: `pascal://scene/current`,
`pascal://scene/current/summary`, `pascal://catalog/items`, and
`pascal://constraints/{levelId}`.
- 3 MCP prompts: `from_brief`, `iterate_on_feedback`, and
`renovation_from_photos`.
- stdio and Streamable HTTP transports.
- `pascal-mcp` CLI binary with `--stdio`, `--http --port`, and `--scene`
flags.
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# @pascal-app/mcp
Model Context Protocol server for the Pascal 3D editor. Drives the
`@pascal-app/core` scene graph from any MCP-compatible AI host.
The server runs headlessly in Node — no browser, no WebGPU, no React — and
exposes the same scene mutations used by the editor UI (create walls, place
items, cut openings, undo, etc.) as MCP tools, resources, and prompts.
## Install
```bash
bun add @pascal-app/mcp # or: npm i @pascal-app/mcp
```
`@pascal-app/core` is a peer dependency; Bun workspaces resolve it automatically.
## Quick start
Launch the server over stdio in one line:
```bash
bunx pascal-mcp # or: npx pascal-mcp
```
Load an initial scene from disk:
```bash
pascal-mcp --stdio --scene ./my-scene.json
```
Expose it as HTTP for remote hosts:
```bash
pascal-mcp --http --port 8787
```
## Claude Desktop config
Edit `~/Library/Application Support/Claude/claude_desktop_config.json`
(macOS) or `%APPDATA%\Claude\claude_desktop_config.json` (Windows):
```json
{
"mcpServers": {
"pascal": {
"command": "bunx",
"args": ["pascal-mcp"]
}
}
}
```
If `bunx` isn't on your PATH, substitute `npx` or point `command` at the
absolute path of the `pascal-mcp` binary inside your project.
## Claude Code config
Via the CLI:
```bash
claude mcp add pascal bunx pascal-mcp
```
Or add to `.mcp.json` at the repo root:
```json
{
"mcpServers": {
"pascal": {
"command": "bunx",
"args": ["pascal-mcp"]
}
}
}
```
## Cursor config
In Cursor settings (`settings.json`):
```json
{
"mcp.servers": {
"pascal": {
"command": "bunx",
"args": ["pascal-mcp"]
}
}
}
```
## Programmatic use
Embed the server in your own Node process using the in-memory transport. The
example below runs a full client/server pair inside a single script — useful
for agent frameworks and tests.
```ts
import { createPascalMcpServer, SceneBridge } from '@pascal-app/mcp'
import { Client } from '@modelcontextprotocol/sdk/client/index.js'
import { InMemoryTransport } from '@modelcontextprotocol/sdk/inMemory.js'
const bridge = new SceneBridge()
bridge.loadDefault()
const server = createPascalMcpServer({ bridge })
const [srvT, cliT] = InMemoryTransport.createLinkedPair()
const client = new Client({ name: 'my-agent', version: '0.1.0' })
await Promise.all([server.connect(srvT), client.connect(cliT)])
const tools = await client.listTools()
console.log('available tools:', tools.tools.map((t) => t.name))
const scene = await client.callTool({ name: 'get_scene', arguments: {} })
console.log(scene)
```
See [`examples/embed-in-agent.ts`](./examples/embed-in-agent.ts) for a
compilable version.
## Tools
All tools validate their inputs and outputs with Zod. Mutation tools are
captured by Zundo's temporal middleware as a single undoable step.
| Name | Purpose | Key input | Output |
| --- | --- | --- | --- |
| `get_scene` | Return the full scene graph. | — | `{ nodes, rootNodeIds, collections }` |
| `get_node` | Fetch a node by id. | `{ id }` | the node, or `InvalidParams` if not found |
| `describe_node` | Node summary with ancestry, children count and properties. | `{ id }` | `{ id, type, parentId, ancestry[], childrenCount, properties, description }` |
| `find_nodes` | Filter nodes by type / parent / zone / level. | `{ type?, parentId?, zoneId?, levelId? }` | `{ nodes: AnyNode[] }` |
| `measure` | Distance between two nodes; area when applicable. | `{ fromId, toId }` | `{ distanceMeters, areaSqMeters?, units: 'meters' }` |
| `apply_patch` | Batched create/update/delete/move, validated and dry-run before commit. | `{ patches: Patch[] }` | `{ applied: number }` |
| `create_level` | Add a new level to a building. | `{ buildingId, elevation, height, label? }` | `{ levelId }` |
| `create_wall` | Add a wall to a level. | `{ levelId, start, end, thickness?, height? }` | `{ wallId }` |
| `place_item` | Place a catalog item on a slab, ceiling, or wall with placement validation. | `{ catalogItemId, targetNodeId, position, rotation? }` | `{ itemId }` or `{ error: 'invalid_placement', reason }` |
| `cut_opening` | Cut a door or window opening into a wall. | `{ wallId, type: 'door' \| 'window', position, width, height }` | `{ openingId }` |
| `set_zone` | Create a zone/room polygon on a level. | `{ levelId, polygon, label, properties? }` | `{ zoneId }` |
| `duplicate_level` | Clone a level and all of its descendants. | `{ levelId }` | `{ newLevelId, newNodeIds[] }` |
| `delete_node` | Delete a node; cascades when `cascade: true`. | `{ id, cascade? }` | `{ deletedIds: [] }` |
| `undo` | Step back through temporal history. | `{ steps? }` | `{ undone: number }` |
| `redo` | Step forward through temporal history. | `{ steps? }` | `{ redone: number }` |
| `export_json` | Serialize the scene graph as JSON. | `{ pretty? }` | `{ json: string }` |
| `export_glb` | Stubbed: GLB export requires the browser renderer. | — | throws `not_implemented` |
| `validate_scene` | Zod-validate every node and parent-child integrity. | — | `{ valid, errors: { nodeId, path, message }[] }` |
| `check_collisions` | Find overlapping items and out-of-bounds placements. | `{ levelId? }` | `{ collisions: { aId, bId, kind }[] }` |
| `analyze_floorplan_image` | Vision tool: extract walls, rooms, and approximate dimensions from a floorplan image. | `{ image, scaleHint? }` | `{ walls, rooms, approximateDimensions, confidence }` |
| `analyze_room_photo` | Vision tool: extract approximate dimensions and fixtures from a room photo. | `{ image }` | `{ approximateDimensions, identifiedFixtures, identifiedWindows }` |
The vision tools require the MCP host to support the sampling capability
(`createMessage`). Hosts that don't will see a structured
`sampling_unavailable` error.
## Resources
| URI | MIME | Purpose |
| --- | --- | --- |
| `pascal://scene/current` | `application/json` | Full `{ nodes, rootNodeIds, collections }` snapshot. |
| `pascal://scene/current/summary` | `text/markdown` | Human-readable summary with node counts, bounding box, and level areas. |
| `pascal://catalog/items` | `application/json` | Item catalog; returns `{ status: 'catalog_unavailable', items: [] }` in headless mode if no catalog is provided. |
| `pascal://constraints/{levelId}` | `application/json` | Slab footprints and wall polygons for the given level — useful as planner context. |
## Prompts
| Name | Args | Purpose |
| --- | --- | --- |
| `from_brief` | `{ brief: string, constraints?: string }` | Guided workflow for turning a prose brief (e.g. "2-bed apartment in 80 m²") into an incremental sequence of `apply_patch` calls starting from an empty site. |
| `iterate_on_feedback` | `{ feedback: string }` | Minimal-diff instructions: examine the current scene, then propose the smallest patch set that satisfies the feedback. |
| `renovation_from_photos` | `{ currentPhotos: string[], referencePhotos: string[], goals: string }` | Chains the vision tools with the scene mutation tools to produce a renovation plan grounded in photos. |
## Limitations
- `export_glb` returns `not_implemented`. GLB export depends on the Three.js
renderer and isn't reachable headlessly without a large additional effort.
- Vision tools require MCP host sampling support. Claude Desktop supports
this; some MCP clients don't.
- Systems (wall mitering, slab triangulation, CSG cutouts, roof / stair
generation) run inside React hooks in the editor. Headless mode doesn't
regenerate derived geometry — but all node data remains fully manipulable.
Consumers that need rendered geometry run `@pascal-app/viewer` in a browser
host.
- Core's `loadAssetUrl` / `saveAsset` are browser-only; items that reference
`asset://<id>` URLs aren't resolvable in Node. Supply absolute URLs or
`data:` URLs for item assets if you need them usable outside the browser.
- `dirtyNodes` accumulates in headless mode because no renderer consumes it.
Call `bridge.flushDirty()` if observability matters to your consumer.
## Development
```bash
bun install
bun run --cwd packages/mcp build
bun test
```
Smoke-test the stdio binary end-to-end:
```bash
bun run --cwd packages/mcp smoke
```
## License
MIT
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/**
* Programmatic `@pascal-app/mcp` usage.
*
* Runs a full MCP client/server pair over the in-memory transport inside a
* single Node process. Useful for agent frameworks and tests that want to
* drive Pascal without spawning a subprocess.
*
* Compile with the package's `tsc --build`, or run directly with Bun:
*
* bun run packages/mcp/examples/embed-in-agent.ts
*/
import { Client } from '@modelcontextprotocol/sdk/client/index.js'
import { InMemoryTransport } from '@modelcontextprotocol/sdk/inMemory.js'
import { createPascalMcpServer, SceneBridge } from '@pascal-app/mcp'
async function main(): Promise<void> {
// 1. Spin up the headless bridge. `loadDefault()` seeds a Site → Building →
// Level stack so the client has something to query immediately.
const bridge = new SceneBridge()
bridge.loadDefault()
const server = createPascalMcpServer({ bridge })
// 2. Link the server to an in-memory client. Exactly the same API surface
// as the stdio / HTTP transports, but without any process boundary.
const [srvT, cliT] = InMemoryTransport.createLinkedPair()
const client = new Client({ name: 'my-agent', version: '0.1.0' })
await Promise.all([server.connect(srvT), client.connect(cliT)])
// 3. Discover available capabilities.
const tools = await client.listTools()
console.log(
'available tools:',
tools.tools.map((t) => t.name),
)
// 4. Inspect the current scene.
const scene = await client.callTool({ name: 'get_scene', arguments: {} })
console.log('scene snapshot:', JSON.stringify(scene, null, 2))
// 5. Find the default level, create a 5 m wall, and undo it.
const levels = await client.callTool({
name: 'find_nodes',
arguments: { type: 'level' },
})
const levelId = (levels.structuredContent as { nodes: Array<{ id: string }> }).nodes[0]?.id
if (levelId) {
const created = await client.callTool({
name: 'create_wall',
arguments: {
levelId,
start: [0, 0],
end: [5, 0],
thickness: 0.2,
height: 2.5,
},
})
console.log('created wall:', created.structuredContent)
const undone = await client.callTool({ name: 'undo', arguments: { steps: 1 } })
console.log('undone:', undone.structuredContent)
}
// 6. Validate and export.
const validation = await client.callTool({ name: 'validate_scene', arguments: {} })
console.log('validation:', validation.structuredContent)
const exported = await client.callTool({
name: 'export_json',
arguments: { pretty: true },
})
console.log('export size:', (exported.structuredContent as { json: string }).json.length)
await client.close()
await server.close()
}
main().catch((err) => {
console.error(err)
process.exit(1)
})
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# Generate a 2-bed apartment from a brief
This example walks through a realistic session with an MCP host (Claude
Desktop, Claude Code, or Cursor) that has `pascal-mcp` configured. The agent
uses the `from_brief` prompt to turn a short brief into a concrete scene.
## The brief
> **User:** Claude, create a 2-bedroom 1-bath apartment in 80 m² in Spain.
The host UI lets the user select the **`from_brief`** prompt and fills in:
```text
brief: "2-bedroom 1-bath apartment in 80 m² in Spain, open-plan living /
kitchen, bathroom on the interior wall"
constraints: "Spanish building regulations; ceiling height 2.5 m"
```
## What the agent does
The prompt returns a system message instructing the agent to start from an
empty site, read the current scene, and emit incremental `apply_patch` calls.
The agent proceeds roughly like this:
### 1. Inspect the current scene
```jsonc
// tool: get_scene
{ "name": "get_scene", "arguments": {} }
```
Response (trimmed):
```jsonc
{
"nodes": {
"site-1": { "type": "site", "id": "site-1", "children": [/* ... */] },
"building-1": { "type": "building", "id": "building-1", "parentId": "site-1" },
"level-1": { "type": "level", "id": "level-1", "parentId": "building-1",
"elevation": 0, "height": 2.5 }
},
"rootNodeIds": ["site-1"]
}
```
The default scene is a Site → Building → Level stack with no walls. The
agent decides to work on `level-1` and targets a 10 m × 8 m = 80 m² outline.
### 2. Create the perimeter walls
The agent chooses a rectangular outline with its origin at (0, 0):
```jsonc
// tool: apply_patch
{
"name": "apply_patch",
"arguments": {
"patches": [
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [0, 0], "end": [10, 0],
"thickness": 0.2, "height": 2.5 } },
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [10, 0], "end": [10, 8],
"thickness": 0.2, "height": 2.5 } },
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [10, 8], "end": [0, 8],
"thickness": 0.2, "height": 2.5 } },
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [0, 8], "end": [0, 0],
"thickness": 0.2, "height": 2.5 } }
]
}
}
```
Response:
```jsonc
{ "applied": 4 }
```
### 3. Create interior partitions
Two bedrooms on the east side, bathroom on the interior wall, open-plan
living / kitchen on the west.
```jsonc
// tool: apply_patch
{
"name": "apply_patch",
"arguments": {
"patches": [
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [5.5, 0], "end": [5.5, 8],
"thickness": 0.15, "height": 2.5 } },
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [5.5, 4], "end": [10, 4],
"thickness": 0.15, "height": 2.5 } },
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [5.5, 5.5], "end": [8, 5.5],
"thickness": 0.15, "height": 2.5 } },
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [8, 4], "end": [8, 5.5],
"thickness": 0.15, "height": 2.5 } }
]
}
}
```
### 4. Define zones
The agent declares the rooms so later queries and item placement can target
them by name:
```jsonc
// tool: set_zone (called once per zone)
{
"name": "set_zone",
"arguments": {
"levelId": "level-1",
"label": "Living / Kitchen",
"polygon": [[0, 0], [5.5, 0], [5.5, 8], [0, 8]]
}
}
// → { "zoneId": "zone-living" }
{
"name": "set_zone",
"arguments": {
"levelId": "level-1",
"label": "Bedroom 1",
"polygon": [[5.5, 0], [10, 0], [10, 4], [5.5, 4]]
}
}
// → { "zoneId": "zone-bed1" }
{
"name": "set_zone",
"arguments": {
"levelId": "level-1",
"label": "Bedroom 2",
"polygon": [[5.5, 5.5], [10, 5.5], [10, 8], [5.5, 8]]
}
}
// → { "zoneId": "zone-bed2" }
{
"name": "set_zone",
"arguments": {
"levelId": "level-1",
"label": "Bathroom",
"polygon": [[5.5, 4], [8, 4], [8, 5.5], [5.5, 5.5]]
}
}
// → { "zoneId": "zone-bath" }
```
### 5. Cut doors and windows
The agent uses `cut_opening` to add entry doors on each interior partition
and windows on the south and east façades:
```jsonc
// tool: cut_opening (called once per opening)
{
"name": "cut_opening",
"arguments": {
"wallId": "wall-south", // perimeter wall [0,0] → [10,0]
"type": "window",
"position": 0.25, // 25% along centerline
"width": 1.2,
"height": 1.2
}
}
// → { "openingId": "window-south-1" }
```
```jsonc
{
"name": "cut_opening",
"arguments": {
"wallId": "wall-bed1", // partition wall to Bedroom 1
"type": "door",
"position": 0.4,
"width": 0.9,
"height": 2.1
}
}
// → { "openingId": "door-bed1" }
```
The agent repeats this for Bedroom 2's door, the bathroom door, and two
more windows on the east façade.
### 6. Validate and report
```jsonc
// tool: validate_scene
{ "name": "validate_scene", "arguments": {} }
```
Response:
```jsonc
{ "valid": true, "errors": [] }
```
The agent then reads the scene summary for its response to the user:
```jsonc
// resource: pascal://scene/current/summary
{ "uri": "pascal://scene/current/summary" }
```
The host displays the returned Markdown: 1 site, 1 building, 1 level, 8
walls, 4 zones, 3 doors, 3 windows; usable area ~78 m²; perimeter ~36 m.
### 7. Iterate
The user follows up:
> **User:** Swap the bathroom and bedroom 2 — I want the bathroom near the
> entrance.
The agent loads the `iterate_on_feedback` prompt and issues a single
`apply_patch` that updates the polygon of `zone-bath` and `zone-bed2` and
moves the corresponding partition walls. Because mutation goes through the
Zustand store, the user can `undo` the change if they dislike it:
```jsonc
{ "name": "undo", "arguments": { "steps": 1 } }
// → { "undone": 1 }
```
## Takeaways
- Mutations batch inside a single `apply_patch` so that `undo` rolls back
the whole logical change.
- Zones are not walls — they're polygon annotations that make later queries
(`find_nodes({ zoneId })`) and planning steps much easier for the agent.
- The agent never needs to speak to `@pascal-app/viewer`: everything the
host sees flows through tools + resources + prompts.
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# Renovate an existing flat from photos
This example shows how an agent can combine the `renovation_from_photos`
prompt with the `analyze_floorplan_image` and `analyze_room_photo` vision
tools to propose a renovation plan grounded in real photos.
> **Note:** the vision tools use MCP sampling (`createMessage`), which
> Claude Desktop supports today. Hosts without sampling support will get a
> structured `sampling_unavailable` error; fall back to the text-only
> `from_brief` prompt in that case.
## The brief
The user drops four photos into the chat:
1. A floorplan PDF page (exported as PNG).
2. A photo of the current living room.
3. A photo of the current kitchen.
4. An inspirational photo from a magazine — a minimal Scandinavian loft.
And types:
> **User:** Claude, help me plan a renovation. Here's the current plan and
> two room photos. I want something like this Scandinavian reference —
> open-plan, neutral tones, keep the footprint.
## What the agent does
The host loads the **`renovation_from_photos`** prompt:
```text
currentPhotos: ["data:image/png;base64,...", "data:image/jpeg;base64,..."]
referencePhotos: ["data:image/jpeg;base64,..."]
goals: "Open-plan living/kitchen, neutral tones, keep the footprint."
```
The prompt tells the agent to (1) analyze the floorplan, (2) analyze each
room photo, (3) seed a scene from the floorplan, (4) compare against the
reference, and (5) propose patches.
### 1. Extract the floorplan
```jsonc
// tool: analyze_floorplan_image
{
"name": "analyze_floorplan_image",
"arguments": {
"image": "data:image/png;base64,iVBORw0KGgoAAAANS...",
"scaleHint": "1 m grid, total footprint ~9.5 m × 7 m"
}
}
```
Under the hood, the tool issues an MCP sampling request to the host with
the image and a structured prompt asking for walls, rooms, and
approximate dimensions. The response is validated against the tool's
output schema:
```jsonc
{
"walls": [
{ "start": [0, 0], "end": [9.5, 0], "thickness": 0.25 },
{ "start": [9.5, 0], "end": [9.5, 7], "thickness": 0.25 },
{ "start": [9.5, 7], "end": [0, 7], "thickness": 0.25 },
{ "start": [0, 7], "end": [0, 0], "thickness": 0.25 },
{ "start": [4.5, 0], "end": [4.5, 7], "thickness": 0.15 },
{ "start": [4.5, 3.5], "end": [9.5, 3.5], "thickness": 0.15 }
],
"rooms": [
{ "label": "Living", "polygon": [[0, 0], [4.5, 0], [4.5, 7], [0, 7]] },
{ "label": "Kitchen", "polygon": [[4.5, 0], [9.5, 0], [9.5, 3.5], [4.5, 3.5]] },
{ "label": "Bedroom", "polygon": [[4.5, 3.5], [9.5, 3.5], [9.5, 7], [4.5, 7]] }
],
"approximateDimensions": { "widthMeters": 9.5, "depthMeters": 7, "areaSqMeters": 66.5 },
"confidence": 0.82
}
```
### 2. Analyze the room photos
```jsonc
// tool: analyze_room_photo
{
"name": "analyze_room_photo",
"arguments": { "image": "data:image/jpeg;base64,/9j/4AAQ..." }
}
```
Response:
```jsonc
{
"approximateDimensions": { "widthMeters": 4.4, "depthMeters": 5.8, "heightMeters": 2.5 },
"identifiedFixtures": [
{ "kind": "sofa", "approximatePosition": [2.2, 3.5] },
{ "kind": "coffee-table", "approximatePosition": [2.2, 2.4] },
{ "kind": "tv-unit", "approximatePosition": [0.3, 2.0] }
],
"identifiedWindows": [
{ "wallHint": "south", "approximateWidth": 1.4, "approximateHeight": 1.5 }
]
}
```
The kitchen photo is analyzed the same way.
### 3. Seed the scene
The agent reads `get_scene`, confirms the default empty Site → Building →
Level is present, and then batch-creates walls matching the floorplan:
```jsonc
// tool: apply_patch
{
"name": "apply_patch",
"arguments": {
"patches": [
{ "op": "create", "parentId": "level-1",
"node": { "type": "wall", "start": [0, 0], "end": [9.5, 0],
"thickness": 0.25, "height": 2.5 } },
/* ...remaining perimeter + partition walls from the vision result... */
]
}
}
```
The agent then calls `set_zone` three times to seed the Living / Kitchen /
Bedroom polygons from the floorplan rooms.
### 4. Cut the identified openings
For each window the vision tool reported, the agent calls `cut_opening`
against the corresponding perimeter wall:
```jsonc
{
"name": "cut_opening",
"arguments": {
"wallId": "wall-south",
"type": "window",
"position": 0.5,
"width": 1.4,
"height": 1.5
}
}
```
### 5. Propose the renovation
Guided by the reference photo's analysis (bright neutrals, open plan,
minimal furnishing), the agent proposes a single logical patch:
- Remove the partition wall between Living and Kitchen.
- Relocate the kitchen island further west.
- Delete the bulky TV unit item; leave the sofa and coffee table.
- Re-label the merged zone `"Open-Plan Living / Kitchen"`.
All of that goes into one `apply_patch`:
```jsonc
{
"name": "apply_patch",
"arguments": {
"patches": [
{ "op": "delete", "id": "wall-partition-living-kitchen", "cascade": false },
{ "op": "update", "id": "zone-living", "data": { "label": "Open-Plan Living / Kitchen",
"polygon": [[0, 0], [9.5, 0],
[9.5, 3.5], [0, 3.5]] } },
{ "op": "delete", "id": "zone-kitchen", "cascade": false }
/* + item moves / deletes for the TV unit etc. */
]
}
}
```
The user can walk back with `undo`; `redo` returns them to the proposal.
### 6. Sanity-check
```jsonc
// tool: validate_scene
{ "name": "validate_scene", "arguments": {} }
// → { "valid": true, "errors": [] }
// tool: check_collisions
{ "name": "check_collisions", "arguments": { "levelId": "level-1" } }
// → { "collisions": [] }
```
The agent reports a summary of the changes plus the approximate new
usable area (from the summary resource), and the user opens the scene in
`@pascal-app/viewer` to see the renovated 3D layout.
## Takeaways
- The vision tools only return **data**. They don't mutate the scene —
the agent is explicit about every structural change via `apply_patch`.
- Photos supply priors (approximate dimensions, fixture types) that a
brief-only workflow can't. Combine them with `from_brief`-style
prompts when the user has both a reference and concrete text goals.
- All renovation steps are a single temporal step per patch, so the user
can compare before/after with `undo` / `redo`.