Revit Model MCP

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List Instances

revit_list_instances

Read-onlyIdempotent

List running Revit processes and active documents to find the exact instance before querying a model. Returns document names, paths, versions, process IDs, and plugin status.

Instructions

List Revit processes and their active documents.

Returns instances with documentName, documentPath, revitVersion, processId and pluginResponding; heartbeats also expose fileChannelVersion, startedUtc and httpPort when available. For file channel v2, pluginResponding means a bounded correlated ping confirmed the PID and startup identity. Busy or unresponsive processes remain listed with pluginResponding=false; processes without a fresh heartbeat remain visible when no document filter is given. Legacy heartbeat presence is only a pre-check. No matching instances return instances=[]. Local and SSH modes use add-in heartbeats with process fallback; fallback records have an empty document and pluginResponding=false. HTTP mode reports only its connected process; transport failures raise errors. Use this tool before choosing a unique document substring for other tools. Every successful result has skipped=[] and skippedCount=0; non-empty skipped means the answer is incomplete.

Input Schema

TableJSON Schema

Name	Required	Description	Default
`document`	No	Case-insensitive substring of the target active document title or file name. Reads require exactly one matching instance; omitted document requires exactly one running instance. Zero or multiple matches fail before publishing. revit_list_instances returns all matching instances, or all running instances when omitted.

Output Schema

TableJSON Schema

Name	Required	Description	Default
No arguments

Schema Changelog

Changes observed during successful MCP inspections.

Changed5 schema fields changedv0.7.0Sep 30, 2026

changedInput schema / properties / document / description

Previous value: -"Case-insensitive substring of the target active document title or file name; default null leaves requests unaddressed, so any instance may respond. Use a unique substring with multiple instances; revit_list_instances instead returns all matching instances, or all instances when omitted."New value: +"Case-insensitive substring of the target active document title or file name. Reads require exactly one matching instance; omitted document requires exactly one running instance. Zero or multiple matches fail before publishing. revit_list_instances returns all matching instances, or all running instances when omitted."

addedOutput schema / additionalProperties
```
Added value: +true
```

removedOutput schema / properties

Removed value: -{
-  "result": {
-    "items": {
-      "additionalProperties": true,
-      "type": "object"
-    },
-    "title": "Result",
-    "type": "array"
-  }
-}

removedOutput schema / required
```
Removed value: -[
-  "result"
-]
```

changedOutput schema / title

Previous value: -"revit_list_instancesOutput"New value: +"revit_list_instancesDictOutput"

Changed1 schema field changedv0.1.1Sep 15, 2026

addedInput schema / properties / document / description

Added value: +"Case-insensitive substring of the target active document title or file name; default null leaves requests unaddressed, so any instance may respond. Use a unique substring with multiple instances; revit_list_instances instead returns all matching instances, or all instances when omitted."

First observedSep 15, 2026

TDQS

A4.3/5.0

Behavior5/5

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

With readOnly/idempotent annotations already covering safety, the description still adds substantial behavioral depth: what pluginResponding means under file channel v2, that busy/unresponsive processes stay listed with pluginResponding=false, mode-specific sourcing (local/SSH heartbeats with fallback vs HTTP single-process), and that transport failures raise errors. This is well beyond what annotations convey.

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?

Purpose and the returned field list are front-loaded, and most sentences carry distinct operational meaning. The closing sentence about skipped/skippedCount overlaps with the available output schema and is slightly redundant, but overall it is tight for the amount of behavior it must convey.

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

Completeness4/5

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

The tool has an output schema and rich annotations, yet the description still covers edge cases (empty results, unresponsive processes, incomplete answers via skipped) and mode differences, so an agent can call and interpret it confidently. A minor gap is that it re-explains return fields the output schema already defines.

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

Parameters3/5

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

Schema coverage is 100% and the single 'document' parameter is already fully documented in the schema, including substring matching and the exactly-one-match read rule. The description adds only marginal semantics (no matches returns instances=[]), so the baseline 3 is appropriate.

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

Purpose5/5

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

The first sentence gives a specific verb and resource ('List Revit processes and their active documents'), and the following sentences enumerate exactly what an instance record contains (documentName, processId, pluginResponding, etc.). This clearly separates it from document-scoped siblings like revit_documents or revit_document_info.

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

Usage Guidelines4/5

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

'Use this tool before choosing a unique document substring for other tools' gives a concrete sequencing rule that positions it as the discovery step ahead of the document-scoped tools. It does not name specific alternatives or exclusions, but the when-to-use context is explicit and actionable.

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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