Revit Model MCP

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Build Walls from CAD

revit_walls_from_cad

Destructive

Generate Revit walls from CAD lines by pairing parallel lines, bridging openings, and joining basic walls in one undo entry; dry_run previews join numbers.

Instructions

Bridge openings, pair parallel CAD lines and join basic walls in one undo entry. Dimensions are mm. Joins Revit rejects are left out and reported as unjoinedEnds with unjoinedReasons; dry_run reports the same join numbers.

Input Schema

Name	Required	Description
`join`	No
`level`	Yes
`cad_id`	Yes
`layers`	Yes
`dry_run`	No
`document`	No	Title or file name substring of the target open document; needed when several are open.
`height_mm`	No
`wall_type`	No
`max_gap_mm`	No
`min_length_mm`	No
`timeout_seconds`	No
`max_thickness_mm`	No
`min_thickness_mm`	No

Output Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed17 schema fields changedv0.10.0Oct 14, 2026

removedInput schema / properties / cad_id / title
```
Removed value: -"Cad Id"
```

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 / height_mm / title
```
Removed value: -"Height Mm"
```
removedInput schema / properties / join / title
```
Removed value: -"Join"
```
removedInput schema / properties / layers / title
```
Removed value: -"Layers"
```
removedInput schema / properties / level / title
```
Removed value: -"Level"
```
removedInput schema / properties / max_gap_mm / title
```
Removed value: -"Max Gap Mm"
```
removedInput schema / properties / max_thickness_mm / title
```
Removed value: -"Max Thickness Mm"
```
removedInput schema / properties / min_length_mm / title
```
Removed value: -"Min Length Mm"
```
removedInput schema / properties / min_thickness_mm / title
```
Removed value: -"Min Thickness Mm"
```

removedInput schema / properties / response_timeout_s

Removed value: -{
-  "default": 600,
-  "maximum": 3600,
-  "minimum": 30,
-  "title": "Response Timeout S",
-  "type": "integer"
-}

addedInput schema / properties / timeout_seconds

Added value: +{
+  "default": 600,
+  "maximum": 3600,
+  "minimum": 30,
+  "type": "integer"
+}

removedInput schema / properties / wall_type / title
```
Removed value: -"Wall Type"
```

removedInput schema / title

Removed value: -"revit_walls_from_cadArguments"

removedOutput schema / title

Removed value: -"revit_walls_from_cadDictOutput"

Addedv0.9.1Oct 7, 2026

TDQS

B3.2/5.0

Behavior4/5

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

Annotations already flag destructiveHint=true and non-idempotent, and the description adds genuine value beyond them: it states the operation is a single undo entry, that Revit-rejected joins are omitted and surfaced as unjoinedEnds/unjoinedReasons, and that dry_run returns the same join numbers. This discloses failure handling and reversibility granularity not present in the annotations.

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

Conciseness4/5

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

Two to three front-loaded sentences: the action leads, followed by unit convention and error/dry-run behavior. Compact and mostly waste-free, though the geometric jargon is dense.

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

Completeness3/5

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

An output schema exists so return values need not be described, and the description usefully covers undo scope and rejected-join reporting. However, for a 13-parameter mutation tool with 8% schema coverage, the near-total absence of parameter documentation leaves a substantial gap.

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 8%, so the description carries the burden, yet it explains almost nothing. It gives only the global unit convention ('Dimensions are mm') and the dry_run behavior, leaving 13 parameters including layers, cad_id, level, wall_type, max_gap_mm, min/max thickness and height 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 name/title plus 'pair parallel CAD lines and join basic walls' make it clear this builds Revit walls from CAD geometry. The mechanical verb phrasing is a bit jargon-heavy, and it does not explicitly differentiate itself from the sibling revit_create_wall, but the action is unmistakable.

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 explicit when-to-use, when-not-to-use, or named alternative versus revit_create_wall or revit_link_cad. The mention that dry_run 'reports the same join numbers' faintly implies a preview-first workflow, but no real usage routing is provided.

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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