What is AEC Model Bridge?
AEC Model Bridge, maintained by A. Sam Mohammad, lets Claude, Codex, Cursor and other MCP clients read and edit the model open in Revit 2024 to 2027. It has two parts: a Python MCP server that talks to the client over stdio, and a native C# Revit add-in that listens on 127.0.0.1 and runs actions on Revit's main thread. Read-only tools run straight away; by default, tools that change the model are blocked until a person approves a plan in the Revit panel or on the command line. The same server also reads IFC files without Revit and drives Rhino, Grasshopper and Speckle.
The repository was created in January 2026, has about 109 stars and 27 forks, and released v1.4.0 on 9 October 2026, with the last push on 28 October 2026. It is licensed GPL-3.0-or-later with a Revit Linking Exception, or under a commercial licence from the maintainer. The README states plainly that nothing in it has yet been verified in a live Revit session.
How to install AEC Model Bridge
uvx --from git+https://github.com/Sam-AEC/aec-model-bridge#subdirectory=packages/mcp-server-revit aec-model-bridgeIs AEC Model Bridge worth it?
AEC Model Bridge has thought harder about letting an AI change a BIM model than any other Revit server we have read about, and it has not yet proved that any of it works. Its own README says nothing has been verified in a live Revit session: the Python server is tested against mock providers, and CI compiles the add-in for Revit 2024 to 2027 without ever starting Revit. That makes it a project to pilot on a copy of a model, not one to point at a live client job.
The architecture is conventional and sound. A Python hub speaks stdio to the client and routes each call to a provider; the Revit provider talks to a native C# add-in on a dynamic loopback port, with a random bearer token created each session. It does not use pyRevit: a pyRevit bridge module exists, but the add-in side that would run the scripts is not implemented. The default setup lists 219 tools, 103 of them for Revit, and the generated catalogue marks 42 of those as reads and 61 as writes. The write side includes revit_execute_python and revit_invoke_method, which reach the whole public Revit API, but both are flagged as mutating and so sit behind the gate.
The gate is the reason to look at this project. In the default ask_first mode the assistant drafts a plan with plan_actions; approve_plan, reject_plan and rollback_plan are never offered to the AI, and a person approves in the Revit panel or with the aec-model-bridge-approve command. An approval is tied to a content hash of the plan, and each approved action runs once. The security document lists the gaps with unusual candour. The panel does not show the assistant's review notes, so the command line's show view is the only full check. Before-values are captured only for revit_set_parameter_value. Approvals do not expire or bind to a document, so a plan drafted in one open Revit can run in another. Any process running as your Windows user can read the panel token and approve, so an AI client with a shell on that account defeats the whole scheme.
Undo is per action. Each parameter or model edit runs in its own named transaction, so Ctrl+Z undoes one action per press; saves, syncs to central and scripts are not covered. Model data the tools return goes to whichever AI provider sits behind your client, which matters when the model is a client's confidential design. The project itself sends no telemetry, and its plans and proof files, which hold element names and parameter values, stay in a local workspace folder.
The licence needs reading before a firm builds on it. GPL-3.0-or-later lets a practice use and modify it internally for free, but the Revit Linking Exception does not allow the code inside a proprietary add-in; that takes a commercial licence. The field is crowded and young. mcp-servers-for-revit/revit-mcp has about 475 stars but no push since February 2026, and Autodesk's own Revit Public MCP Server is a technical preview for Revit 2027.2 only, whose help page asks you to review proposed changes and back up the model. AEC Model Bridge covers four Revit years and has the strongest written answer to who approves a change; what it lacks is the evidence that the answer holds inside Revit.
Where it earns its place
A BIM coordinator at a 60-person architecture practice
Triage model warnings before the weekly coordination meeting
Run the server in look_only mode, ask the assistant to group revit_get_warnings output by description and list the affected element IDs. Nothing can change the model in that mode, so the risk is limited to what the warnings reveal to the AI provider.
A BIM manager cleaning up parameters on a hospital project
Fill in missing Comments or Mark values across hundreds of walls
Have the agent draft the batch with plan_actions, read it with aec-model-bridge-approve show, then approve and read the values back. Keep plans to a few hundred actions, and expect several Ctrl+Z presses to undo one plan.
A contractor's design manager receiving consultant models
Check an IFC file's storeys and properties without opening Revit
Use ifc_get_spatial_structure, ifc_get_properties and ifc_validate, which read IFC through IfcOpenShell on any machine. No Revit seat is needed for this part, and the tools do not edit the file.
A software lead at an engineering firm with in-house Revit tools
Decide whether to fold the bridge into the firm's own add-in
Evaluate the tool list in mock mode or the Docker image first. Shipping it inside a proprietary add-in needs the commercial licence, whose terms and price are agreed with the maintainer and not published.
Before you commit
- Setup
- Needs Windows 10 or 11, a licensed Revit 2024 to 2027, Python 3.11 or later and uv. The v1.4.0 Windows installer picks your Revit years, needs no admin rights and can configure Claude Desktop and VS Code after backing up their settings; otherwise add the uvx line to the client and run install.ps1 for the add-in. An AEC Bridge ribbon tab and a /health check confirm the connection.
- Integrations
- 219 tools in the default setup: 103 for Revit, plus IFC, Rhino and Grasshopper, Speckle, snapshot QA/QC modules and an in-progress Navisworks provider. Tools carry readOnlyHint and destructiveHint annotations. Setup is documented for Claude Desktop, VS Code with GitHub Copilot, Cursor and Codex; other stdio clients are untested.
- Data and privacy
- Server and add-in run locally and the bridge listens on loopback only; whatever the tools read from the model goes to your AI provider, and the panel's built-in chat sends to Anthropic. No telemetry. Plans and proof bundles store element names and parameter values in the workspace folder, and file access is limited to MCP_REVIT_ALLOWED_DIRECTORIES.
- Cost at scale
- The software is free under the GPL. The real costs are a Revit subscription for every person who runs it live, the AI client's plan or tokens, and the context taken by a 219-tool list in every session. Commercial licence prices are not published.
- Limits
- Live Revit behaviour is unverified throughout; the README describes the dev branch, which may run ahead of the latest release. Plan execution slows with size, so plans should stay under a few hundred actions. rollback_plan has no panel button or command, and the official MCP Registry entry still lists v1.0.1.
What’s good
- Write tools blocked until a person approves a hashed plan
- Approval tools never exposed to the AI
- Covers Revit 2024 to 2027, plus IFC without Revit
- Security limits documented in unusual detail
What’s not
- Never verified in a live Revit session, by its own account
- Panel approval hides the assistant's review notes
- Approvals do not expire or bind to a document
- GPL blocks embedding in proprietary add-ins without a paid licence
Best for
BIM coordinators and digital practice leads willing to pilot an agent on copies of Revit models, where a human sign-off on every change is a requirement.
AEC Model Bridge: common questions
- Is AEC Model Bridge worth it?
- An unusually careful approval design for putting an agent inside Revit, from a maintainer honest enough to say none of it has yet run in a live Revit session. We rate it 3.4 out of 5.
- How much does AEC Model Bridge cost?
- Free under GPL-3.0-or-later with a Revit Linking Exception, or a commercial licence on request (price not published). Needs a licensed Revit 2024 to 2027.
- What are the downsides of AEC Model Bridge?
- Never verified in a live Revit session, by its own account; panel approval hides the assistant's review notes; approvals do not expire or bind to a document; gPL blocks embedding in proprietary add-ins without a paid licence.
- Who is AEC Model Bridge best for?
- BIM coordinators and digital practice leads willing to pilot an agent on copies of Revit models, where a human sign-off on every change is a requirement.
- How much does AEC Model Bridge cost for a team or in production?
- The software is free under the GPL. The real costs are a Revit subscription for every person who runs it live, the AI client's plan or tokens, and the context taken by a 219-tool list in every session. Commercial licence prices are not published.
- Is AEC Model Bridge safe for company data?
- Server and add-in run locally and the bridge listens on loopback only; whatever the tools read from the model goes to your AI provider, and the panel's built-in chat sends to Anthropic. No telemetry. Plans and proof bundles store element names and parameter values in the workspace folder, and file access is limited to MCP_REVIT_ALLOWED_DIRECTORIES.
Answers checked Oct 31, 2026.