Model MCP

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Place Families

revit_place_families

Destructive

Load optional families and place instances at coordinates or by room in Revit, combining all changes into one transaction and undo entry.

Instructions

Load optional families and place instances in one transaction and undo entry.

Input Schema

Name	Required	Description
`load`	No
`dry_run`	No
`at_rooms`	No
`document`	No	Title or file name substring of the target open document; needed when several are open.
`placements`	No
`stop_on_error`	No
`timeout_seconds`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed28 schema fields changedv0.10.0Oct 14, 2026
- removedInput schema / $defs / FamilyPlacement / properties / family / title
```
Removed value: -"Family"
```
- removedInput schema / $defs / FamilyPlacement / properties / host_id / title
```
Removed value: -"Host Id"
```
- removedInput schema / $defs / FamilyPlacement / properties / level / title
```
Removed value: -"Level"
```
- removedInput schema / $defs / FamilyPlacement / properties / parameters / title
```
Removed value: -"Parameters"
```
- removedInput schema / $defs / FamilyPlacement / properties / rotation_deg / title
```
Removed value: -"Rotation Deg"
```
- removedInput schema / $defs / FamilyPlacement / properties / type_name / title
```
Removed value: -"Type Name"
```
- removedInput schema / $defs / FamilyPlacement / properties / x_mm / title
```
Removed value: -"X Mm"
```
- removedInput schema / $defs / FamilyPlacement / properties / y_mm / title
```
Removed value: -"Y Mm"
```
- removedInput schema / $defs / FamilyPlacement / properties / z_mm / title
```
Removed value: -"Z Mm"
```
- removedInput schema / $defs / FamilyPlacement / title
```
Removed value: -"FamilyPlacement"
```
- removedInput schema / $defs / RoomPlacement / properties / family / title
```
Removed value: -"Family"
```
- removedInput schema / $defs / RoomPlacement / properties / level / title
```
Removed value: -"Level"
```
- removedInput schema / $defs / RoomPlacement / properties / parameters / title
```
Removed value: -"Parameters"
```
- removedInput schema / $defs / RoomPlacement / properties / rooms / title
```
Removed value: -"Rooms"
```
- removedInput schema / $defs / RoomPlacement / properties / rotation_deg / title
```
Removed value: -"Rotation Deg"
```
- removedInput schema / $defs / RoomPlacement / properties / type_name / title
```
Removed value: -"Type Name"
```
- removedInput schema / $defs / RoomPlacement / properties / z_mm / title
```
Removed value: -"Z Mm"
```
- removedInput schema / $defs / RoomPlacement / title
```
Removed value: -"RoomPlacement"
```
- changedInput schema / properties / document / description
```
Previous value: -"Case-insensitive substring of the target open document's title or file name. Required to disambiguate when the Revit process has more than one document open; omit only when a single document is open (the active document is used). An unknown or ambiguous reference is rejected before any change."New value: +"Title or file name substring of the target open document; needed when several are open."
```
- removedInput schema / properties / document / title
```
Removed value: -"Document"
```
- removedInput schema / properties / dry_run / title
```
Removed value: -"Dry Run"
```
- removedInput schema / properties / load / title
```
Removed value: -"Load"
```
- removedInput schema / properties / placements / title
```
Removed value: -"Placements"
```
- removedInput schema / properties / response_timeout_s
```
Removed value: -{
-  "default": 600,
-  "maximum": 3600,
-  "minimum": 30,
-  "title": "Response Timeout S",
-  "type": "integer"
-}
```
- removedInput schema / properties / stop_on_error / title
```
Removed value: -"Stop On Error"
```
- addedInput schema / properties / timeout_seconds
```
Added value: +{
+  "default": 600,
+  "maximum": 3600,
+  "minimum": 30,
+  "type": "integer"
+}
```
- removedInput schema / title
```
Removed value: -"revit_place_familiesArguments"
```
- removedOutput schema / title
```
Removed value: -"revit_place_familiesDictOutput"
```
Addedv0.9.1Oct 7, 2026

TDQS

C2.8/5.0

Behavior3/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare destructiveHint=true, readOnlyHint=false and idempotentHint=false, so the safety profile is covered. The description usefully adds that everything happens in one transaction and one undo entry, but it omits the notable dry_run parameter and stop_on_error behavior, which materially affect what the call actually does.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness3/5

Is the description appropriately sized, front-loaded, and free of redundancy?

It is a single front-loaded sentence with no wasted words, which is good structure. But the brevity here reflects under-specification rather than economy, since core behaviors and parameters go unmentioned.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness2/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For a destructive, 7-parameter batch placement tool with nested placement objects, the description is too thin. It could reassure the agent about dry_run safety, document targeting, and atomic rollback, but instead leaves most operational detail to a schema that is only 14% documented.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters2/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is only 14% across 7 parameters, so the description must carry the load, and it largely does not. 'Load optional families' gestures at the load parameter and 'place instances' at placements, but dry_run, document, stop_on_error, timeout_seconds, and the at_rooms/placements structure are entirely unexplained.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose4/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb+resource set: optionally loading family definitions and then placing family instances. However, it never distinguishes this batch tool (families, plural) from the very similar sibling revit_place_family, leaving the agent to infer the batch nature from the name alone.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines2/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

There is no when-to-use guidance, no prerequisites (e.g. an open document), and no routing to alternatives such as revit_place_family or revit_load_family. The agent gets no signal about when this is the correct tool versus its near-duplicate sibling.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.

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