BIM-MODE Connector for Revit

Author: Hire me. Upgrade prepared 19 October 2026.

Supported build targets

Compilation is not a live-validation claim. See VALIDATION.md for the tested scope. Revit 2021 lacks native PDF export and ceiling creation APIs. Four bundled handlers (PDF export and create/bind/remove shared parameters) explicitly report their 2022+ requirement on 2021; floor creation uses the older API. All other operations still require suitable model content and valid parameters.

Related MCP server: Revit MCP Server

Native tools and compatibility

The existing BIM-MODE native category, element, view, sheet, and documentation tools remain. There are now 224 bundled native handlers, with their own real schemas, running in the selected Revit process without a separate server or the BIM-MODE Python engine. Apache-2.0 attribution and third-party notices are included.

The old extended catalog is retained for provenance/tests, but its approximate aliases are no longer registered. Fourteen old gateway/lifecycle aliases are retired; see native-tool-inventory.json. BIM-MODE provides its own session selection, C# execution, custom tools, and change-event history below. BIM-MODE does not include a separate gateway process, history database, failure store, asynchronous operation store, model-lineage reconciliation, or suggestion-driven baker.

Gateway mode exposes search/describe/call tools. Use bim_search_tools, then bim_describe_tool, then bim_call_tool. bim_capabilities reports registered providers and limits; counts do not mean every tool has been live-tested.

Write and run Revit code

• bim_validate_csharp: compile a C# body without executing it.

• bim_execute_csharp: compile/run C# on Revit's API thread.

• bim_bake_tool: compile and persist a reusable custom_<name> tool.

• bim_list_baked_tools: list saved tools; invoke them through bim_call_tool.

• bim_change_history: recent committed document events, including manual edits and undo/redo, with affected element IDs and transaction names.

C# has uiapp, uidoc, doc, and a JsonObject named args. Return JSON-serializable values. Imports include System, LINQ, collections, Revit DB/UI, and JSON nodes. A transaction is supplied: do not start another top-level transaction.

Example arguments to bim_execute_csharp:

{"code":"return new { title = doc.Title, levels = new FilteredElementCollector(doc).OfClass(typeof(Level)).GetElementCount() };","preview":true}

preview defaults to true and rolls back model edits. Use false to commit. Errors roll back the enclosing transaction. Code is full-trust, not a sandbox: filesystem, network, and other external side effects cannot be rolled back. Running code must return promptly; there is no safe forced timeout for code already on Revit's UI thread. Read-only mode blocks execution/baking, and destructive approval applies to both. Python runs through bundled IronPython 3.4.2 in the same Revit process. Use bim_validate_python to check syntax and run_python_script (or execute_revit_code) to run it. Variables are doc, uidoc, uiapp, __revit__, and the Python dictionary args; assign JSON-compatible output to result. Preview defaults to true. The runtime is full-trust and cannot safely interrupt code already running on Revit's API thread. CPython binary packages and newer Python syntax are not supported. No external Python installation, pyRevit service or additional MCP server is required.

bim_engine_health checks provider catalogs, bundled Python execution and Revit API responsiveness. The connector no longer registers the external BIM-MODE HTTP provider or approximate basic aliases. Those basic commands now have local implementations and explicit input schemas. Specialized workflows from the old APIAI Python extension are not imported automatically: search the registered capabilities before relying on a particular legacy workflow. This is an integrated execution foundation, not a claim that every legacy workflow has been migrated.

Recipes: %APPDATA%/BIM-MODE/recipes/. History: Documents/BIM-MODE/logs/changes-<pid>.jsonl. History rotates at 20 MB; it stores change events, not previous geometry snapshots.

Three concurrent sessions

The add-in claims the first available port from 48890, 48891, 48892 (configurable base). A fourth process is refused if all three slots are occupied. Discovery is per process, so one shutdown cannot remove another session's record.

The stdio bridge exposes bim_list_sessions and bim_select_session (argument pid). With multiple sessions, choose explicitly. Each bridge stays pinned to its selected PID; if that process closes, it returns an error instead of selecting another model. You can also launch with --pid <PID> or a fixed --url.

All active providers execute inside their selected Revit process. The archived pyRevit route is no longer installed or called by the connector.

Install (GitHub / gitinstall & npm)

Option 1: GitHub installer (gitinstall.ps1)

git clone https://github.com/BIM-MODE/BIM-MODE-Connector.git
cd BIM-MODE-Connector
powershell -NoProfile -ExecutionPolicy Bypass -File gitinstall.ps1 -RevitVersion 2026

Or install directly from PowerShell:

irm https://raw.githubusercontent.com/BIM-MODE/BIM-MODE-Connector/main/gitinstall.ps1 | iex

Option 2: npm / npx (MCP stdio bridge wrapper)

npx github:BIM-MODE/BIM-MODE-Connector --install 2026
npx github:BIM-MODE/BIM-MODE-Connector

Once published to the npm registry (npm publish):

npm install -g bim-mode-mcp
bim-mode-mcp --install 2026

Option 3: Release archive

Download the release ZIP from GitHub Releases, extract it, and run INSTALL.bat or ./install.ps1 -RevitVersion 2026 (supports Revit 2021-2027).

The installer uses a new version folder, backs up the manifest, and takes effect in a new Revit process. It never closes existing models. The bridge has its own folder so its .NET 8 core cannot overwrite the .NET Framework core used by older Revit. Use the ribbon's Connect AI apps feature only for clients you intend to configure.

Attribution and support

Part of the bundled handler source is Apache-2.0 licensed open-source code. See LICENSE-APACHE-2.0.txt and THIRD-PARTY-NOTICES.txt. Modified files are marked. No third-party or Autodesk endorsement or vendor support is included. No comparative performance or reliability claim against other products has been established.

New model evidence tools

• bim_capture_model_snapshot: persist a scoped instance-data snapshot with unique IDs and selected parameters.

• bim_compare_model_snapshots: report additions, removals and changed captured values; reject mismatched scopes.

• bim_list_model_snapshots: discover saved snapshots across sessions (latest 100).

• bim_check_parameter_rule: required-value, duplicate-value or regex checks returning failing UniqueIds.

These tools do not compare geometry or certify building-code compliance. Parameter names are exact, localized instance names; numeric values use Revit internal units. Missing parameters are distinguished from empty values. Capture refuses truncation and ambiguous parameter names. Snapshot capture writes local files and goes through the write approval gate, without opening a model transaction. See VALIDATION.md for the precise live-test scope.

Connecting AI apps

The AI Connector > Connect AI apps window sets up the following apps with one click (Connect, Reconnect, Remove): Claude Desktop, Claude Code, Cursor, Windsurf, Gemini CLI, VS Code (Copilot) and Insiders, LM Studio, Kimi (desktop app and Code CLI), Kimi CLI (older), OpenAI Codex, Google Antigravity, DeepSeek Harness, PawWork and Cline (app, CLI and VS Code extension). ChatGPT and OpenCode have a Setup guide button. Apps that only run in a browser or offer Google-hosted connectors only (for example the Gemini desktop app) cannot start a local MCP program and cannot be connected. Restart the AI app (or start a new chat) after connecting.

Code mode helpers

bim_run_code runs one Python script that calls many tools and returns only the answer. Besides tools.call, it offers tools.recipe('model_summary' | 'qa' | 'coordination' | 'sheets') (a whole check in one call), tools.many([[name, args], ...]), tools.pick(rows, 'id', 'name'), tools.brief(x, 20), tools.models(), tools.links(), tools.safe(name, args) and tools.help(topic). Results over about 12,000 characters are shortened automatically (pass full_output=true to keep everything). There is no default time limit; timeout_sec sets one. Tool-call waits in the apps are set to 24 hours.