revit-bridge

Intent bridge between designers and AI for Autodesk Revit: an MCP server that executes code in a running Revit, keeps a library of reusable capability packs, and refuses to run anything the designer has not confirmed.

The package contains no model SDK, no vector store and no web framework. Your MCP host (Claude Desktop, Claude Code, any MCP client) brings the model; the revit-bridge-addin inside Revit executes the code.

Install

Prerequisites: Python 3.11+ with uv (for uvx), Revit 2026 with the add-in installed and its local TCP listener on (default 127.0.0.1:18080).

Claude Desktop — claude_desktop_config.json:

{
  "mcpServers": {
    "revit-bridge": {
      "command": "uvx",
      "args": ["revit-bridge"]
    }
  }
}

Claude Code - the plugin (skill + MCP server + confirmation hook, recommended):

/plugin marketplace add revitbridge/revit-bridge
/plugin install revit-bridge@revit-bridge

The plugin's .mcp.json starts the server with uvx; its hooks/hooks.json denies execute_code / run_tool calls that carry no confirmation token (uv run executes plugin/hooks/spec_gate.py, so uv must be on PATH). The skill is also installable on its own with npx skills add revitbridge/revit-bridge.

MCP server only, without the skill and hook:

claude mcp add revit-bridge -- uvx revit-bridge

Any MCP client — run uvx revit-bridge as a stdio server. Pass connection settings through environment variables (see Configure), for example in the env block of the host's server entry.

Your own host — the same flow is a package API: revit_bridge.execution (run_pack, run_code, revalidate) with your own ToolStore, Gate, Ledger and Revit client, plus revit_bridge.host_instructions() for a host whose interface does the confirmation.

From a checkout: uv sync then uv run revit-bridge.

Use

1. Start Revit, open a project and make sure the add-in is listening.

2. Check the connection:

   uvx revit-bridge check
   

   Prints host, port, whether a token is set, the open document's title (document, or document_error when the add-in answered but could not read it) and "status": "connected"; the exit code is 0 when the add-in answered, 1 otherwise.

3. In your host, the flow is snapshot → questions → confirmation → execution → validation:

   • get_project_snapshot — what the model contains (units, levels, grids, family types, selection, …); query(kind, args) answers single read-only questions (levels, grids, family_types, elements, selection, view_elements, units, counts). Neither needs confirmation.
   • list_tools — the capability packs (eight built-ins such as create_wall, create_structural_column, query_levels, plus your own); missing_params(tool, known) — the questions still open, with the real options; get_tool_choices(name) — levels, types or elements for a pack's dynamic parameters.
   • reconcile(spec, snapshot) — a draft TaskSpec against the model: values that do not exist, missing parameters, readings to confirm (units, "on F2"), a stale snapshot.
   • confirm_spec(spec) with the TaskSpec the designer confirmed, then run_tool(name, params, token) with exactly the confirmed values.

   execute_code takes arbitrary C# for tasks no pack covers. The code runs inside Revit with document in scope and a transaction already open; end it with return <object>;. solidify_tool saves code that worked as a new pack.

   A pack's validator (created_ids, count_delta or param_equals) asserts the outcome after the run: success is true only when Revit succeeded and the assertion held, and every execution leaves a line in the evidence ledger (evidence, validate(evidence_id)).

Confirmation gate. execute_code and run_tool return confirmation_required without a token. A token comes only from confirm_spec(spec): the TaskSpec lists every parameter with its value, source and evidence; the server validates it and issues a one-time token bound to exactly that tool and those parameters (or that code). Running anything else with it, reusing it, or using it after 10 minutes fails with confirmation_invalid. missing_params and reconcile help build the spec. Hosts that run their own confirmation flow can set REVIT_BRIDGE_ALLOW_UNCONFIRMED=1.

Resources: revit://stats, revit://tools/{name}, revit://evidence/recent, revit://connection-status.

The plugin ships an eval suite (plugin/evals/, the three baseline tasks and two second-turn cases, with mocks of the MCP server). Run it by hand from plugin/ with claude plugin eval . (on Windows in a UTF-8 console: chcp 65001 first, or the Chinese prompts reach the model garbled); it is not part of CI.

Configure

Development:

uv sync
uv run pytest
uv build
uvx --from . revit-bridge check

License: MIT. Issues and discussion: https://github.com/revitbridge/revit-bridge/issues.