rvt-mcp

What it is

An early all-C# MCP implementation for Revit — researched and implemented since March 2026.

rvt-mcp is a local bridge between an MCP client and a running Revit session. A .NET 8 server talks MCP over stdio; a thin add-in per Revit year (2022–2027) runs inside Revit and is reached over localhost TCP (≤2024) or a named pipe (≥2025). Nothing leaves the machine, it is C# end to end, and lengths are millimetres at the tool boundary. Details: ARCHITECTURE.md.

Agents get a typed tool surface for common Revit work, a C# escape hatch for everything else, and an optional way to turn repeated patterns into personal tools (ToolBaker): start from a shared runtime and grow your tools on top. Family Editor authoring is out of scope for now.

Related MCP server: RevitMCPBridge2026

Install

Let an AI agent install it for your target client. Use an agent that can run PowerShell and edit local files on this Windows machine (Claude Code, Codex, Cursor, …), not a chat session without local tools. The agent installing it can be different from the client where you will use Revit tools. It follows AGENTS.md, previews changes and asks before applying them; you may still need to approve a UI step or restart an app.

For Claude Desktop, paste:

Install rvt-mcp for Claude Desktop on this Windows machine.
First read https://github.com/bimwright/rvt-mcp/blob/master/AGENTS.md.
Configure only Claude Desktop, not other clients. Inspect existing installations,
preview changes and ask before writing. Tell me if I need to use the UI or restart an app.

For another client, replace Claude Desktop with its name. Claude Code and Claude Desktop are different targets: installer option claude means Code; claude-desktop means Desktop.

Or run the installer yourself (Claude Desktop, direct config). Close Revit and fully quit Claude Desktop (including its tray process), then in PowerShell:

$tag = (Invoke-RestMethod https://api.github.com/repos/bimwright/rvt-mcp/releases/latest).tag_name
$dir = "$env:TEMP\RvtMcp.Setup-$tag-win-x64"
Invoke-WebRequest "https://github.com/bimwright/rvt-mcp/releases/download/$tag/RvtMcp.Setup-$tag-win-x64.zip" -OutFile "$dir.zip"
Expand-Archive "$dir.zip" -DestinationPath $dir -Force
powershell -ExecutionPolicy Bypass -File "$dir\install.ps1" -WhatIf -Client claude-desktop
# Review the preview before applying:
powershell -ExecutionPolicy Bypass -File "$dir\install.ps1" -Client claude-desktop

This installs the add-in for every detected Revit 2022–2027 and registers rvt-mcp only in Claude Desktop (the config is backed up first). For Claude Code use -Client claude; for multiple requested clients use a comma list. Omitting -Client wires every detected client; -Client none leaves configs untouched. The server lives at %LOCALAPPDATA%\Bimwright\rvt-mcp\server\current\rvt-mcp.exe (per-client steps, including Desktop classic/MSIX paths).

Check it works: restart your AI client, open a model in Revit, start MCP from the ribbon (Add-Ins → RvtMcp) and ask the agent to call revit_get_current_view_info. It should return the active view's name and type.

Upgrade: close Revit and gateway clients, back up the product data folder, then run the new installer in place without uninstalling first. Settings and ToolBaker data are kept. MCPB users use -Client none, update Setup and extension from the same release, then check Desktop settings and permissions before reconnecting. See the upgrade sequence. Uninstall: uninstall.ps1 -Yes removes add-ins and the server; personal data is kept unless you add -Purge. To remove client entries too, first run install.ps1 -Uninstall -Client auto.

Upgrading from v0.8.1 or v0.6.x: those versions keep your settings and ToolBaker data in %LOCALAPPDATA%\RvtMcp\; v1.0.0 uses %LOCALAPPDATA%\Bimwright\rvt-mcp\, and the installer moves the old folder there. Close Revit and every MCP client first, because a running old server locks the folder. Check in PowerShell with Test-Path "$env:LOCALAPPDATA\RvtMcp". If the installer stops with Both … exist or Could not move …, it has undone what it moved: keep the folder that holds your settings and ToolBaker data, rename the other one (for example to RvtMcp.bak) instead of deleting it, close the clients that were using it, and run the installer again.

Claude Desktop extension (MCPB, optional): direct config above is the default for agent-assisted installs. If you want the extension/settings UI, use Setup with -Client none, then install the .mcpb through Desktop's extension UI. Choose one route, not both. -Client none does not remove an existing manual registration. Use the bundle from the same selected release as Setup; it does not install the gateway/add-ins and requires that release's exact server build. Check the release notes for its signing status. See MCPB installation and settings.

Videos

Community videos of rvt-mcp at work. Install steps shown in a video can be older than this README — follow the steps above.

• Connecting ChatGPT Astra to Revit | Testing AI Changes in a Real Project — Revit Mentor

• Exploring Revit + GPT 6 Astra — BIM Pure

• GPT-6 Astra Built a Revit House in 14 Minutes — Archi Vlogs

Tools

Counts exclude your personal baked tools. The installer writes the seeded default only when rvtmcp.config.json doesn't already set toolsets — your own list survives upgrades, and removing the key (or setting your own CSV) returns a bare server to the 46-tool surface. Read-only filters individual tools by ReadOnly=true, including reads inside mixed toolsets. Tools that can write files are excluded even when their default output is inline.

send_code, ToolBaker, ribbon and languages

• revit_send_code_to_revit (on by default) compiles and runs a C# body inside Revit when no typed tool fits; --read-only or --disable-send-code removes it. See docs/send-code.md, and docs/stairs-workflow.md for stairs.

• ToolBaker: revit_list_baked_tools / revit_run_baked_tool need --toolsets toolbaker. Adaptive bake (--enable-adaptive-bake, off by default) suggests tools from repeated calls; nothing is added until you accept one. Bake compiles inside Revit — no Visual Studio needed. See docs/bake.md.

• Ribbon: start or stop the connection, open History to search and re-run past calls, and switch completion Toasts (on by default).

• UI languages: the add-in UI comes in 15 languages and follows Revit's UI language; change it with the Language button in the ribbon slide-out — it opens Settings → General → Language (BIMWRIGHT_UI_LANGUAGE still wins). Tool names and payloads stay English. See docs/localization.md.

Why activity toasts exist

Toasts are work feedback, not just decoration. They grew out of three practical needs:

• Free users from watching the chat. In real-world MCP workflows, an AI agent can work for a long time while Revit gives little visible feedback. Watching the chat just to check whether the agent is doing anything wastes attention. The activity card reports completed tool calls so users can turn to other work between updates.

• Support multitasking. The maintainer develops and repeatedly tests several desktop applications in parallel. Compact notifications make it easier to follow those sessions without keeping every chat in view.

• Modernize the experience. Revit-side feedback makes automation feel more responsive and understandable, without interrupting work with modal dialogs.

A toast reports a tool result, not progress inside a running tool or completion of the entire task. Repeated results share one card; notifications may wait while Revit is minimized or blocked by a modal dialog. They do not replace reviewing the agent's work.

Each card names the gateway and Revit year (for example rvt-mcp 2022), the latest tool, and the Success · Failed · Capture counts. A capture preview stays on the card for at least 5 seconds.

Deliberate hover opens an activity timeline showing the newest three results, each with its local completion time (HH:mm:ss). Scroll up for earlier calls in that card. Incoming results follow the bottom with a short glide-in (the rows rise, the new row fades in and its outcome dot pops; none of this with reduced motion); while you read older calls, your position stays put. Click inside the timeline to read without closing it; clicking the rest of the card opens History. This works with branding off. Summaries are bounded and redacted, stay in memory only, and clear when the card closes. Script objects/arrays show counts; an incomplete survey remains explicitly incomplete. Server-local tools do not gain toast coverage from this UI change.

Notifications are on by default and can be turned off. In Settings → Toast, choose the idle duration (10/20/30/60 seconds; default 20) and Show branding (off by default), which shows the wordmark on hover. The choice applies immediately and is saved across Revit restarts; users do not need to display branding to get activity feedback.

Position: choose Horizontal alignment (Left/Right) and Vertical alignment (Top/Bottom) independently in Settings → Toast; the default is top-left. Changes apply to the open card and are saved immediately, and changing a corner clears any saved drag position. Turn on Allow dragging the card to move it by its title row; a plain click still opens History. Turning drag off keeps the saved position, turning it on restores it, and Reset position clears it. The position is stored relative to the Revit window and kept inside the monitor's work area. A card anchored at the bottom grows upward, and falls back to the other side when there is no room. Motion follows the Windows animation setting. A failed save is shown under the setting while the choice stays active for the session. Hovering the latest-tool line or a timeline row shows the sanitized result, Success/Failed, the completion time and the measured duration when available. Coordination between toasts of several Autodesk applications is not part of this.

Prompts

v1.0.0 provides six MCP prompts — pick /mcp__rvt-mcp__revit_<name> (Claude Code) or the prompts menu (Claude Desktop), and the agent follows the script with the tools it already has:

• revit_getting_started — orient in the open model (read-only, works on defaults).

• revit_drawing_layout — supply request: arrange the viewports of one sheet. Reads real sheet-space positions first (revit_get_viewport_geometry), agrees the alignment with you, shows a dry-run plan (revit_align_viewports), moves only after you confirm, then reads back. Needs query,sheets,view,meta. In read-only mode it reports and proposes only.

• revit_change — supply change: survey relationships, agree the smallest scope for this request, confirm the concrete proposal before writing, then read back and record the reason in the conversation. Needs query,meta; works without send_code. In read-only mode it stops at the survey/proposal. Missing or incomplete evidence stays "not checked"; readback is not a complete inventory of indirect changes, and the record is not a persistent change database.

• revit_model_audit — health audit: warnings, families, dry-run purge candidates (needs workflows,families,lint,meta).

• revit_pre_issue_check — checks resolved sheets before issue (needs sheets,view,annotation,lint,meta). Supply sheet numbers/IDs, an explicit number/name filter, or all; a named sheet set needs its member sheets. Sampled model warnings and incomplete checks are reported as NOT VERIFIED, not a sheet-level pass.

• revit_stairs — guided stair creation through send_code (writes only after your confirmation). Includes the transaction/failure/cleanup template; no source checkout is needed.

If a prompt's toolsets aren't enabled, it answers with the exact --toolsets line to add — nothing runs half-configured. Read-only protection stays on when the missing tools allow it; prompts requiring write-capable toolsets explain the conflict rather than silently changing configuration. Prompts are instructions for the agent, not server-enforced workflow locks.

Configuration

Since v1.0.0 the server reports _changes and local per-model _history. History defaults on independently of call logs; use --disable-change-history to disable recording. The meta tools revit_record_change, revit_get_change_records and revit_resolve_history_identity attach reasons to explicit call IDs, query stored changes and record the owner's history choice after a copy or Save As. See change tracking for privacy, limits and recovery.

revit_survey_change_impact is a tool in query: a bounded, read-only survey of ten relationship groups, including with send-code disabled. scopeThreshold is required for each request; view/schedule iteration is opt-in through maxViews > 0. Partial results remain explicit and parameter observations are not trusted history snapshots. See change-impact survey.

Precedence, high wins: CLI → env (BIMWRIGHT_*) → %LOCALAPPDATA%\Bimwright\rvt-mcp\rvtmcp.config.json.

After changing server flags, restart the MCP connection so the client picks up the new tool list.

Permissions & auto mode

These controls arrive in v1.0.0. The v0.8.1 package does not include the new switches or per-tool read-only filtering. send_code and run_baked_tool must be called directly; batch_execute rejects them.

MCP annotations describe each tool's document/file effects. Transient selection, active-view and zoom changes count as read-only. send_code has no annotations: keep it out of automatic permissions and confirm each arbitrary-code call. For Claude Code, copy only the read-only allow list below; do not allow the broad mcp__rvt-mcp__* wildcard. The list covers --toolsets all; your selected toolsets may expose fewer tools.

{
  "permissions": {
    "allow": [
      "mcp__rvt-mcp__revit_activate_view",
      "mcp__rvt-mcp__revit_ai_element_filter",
      "mcp__rvt-mcp__revit_analyze_geometry_complexity",
      "mcp__rvt-mcp__revit_analyze_mep_network",
      "mcp__rvt-mcp__revit_analyze_model_statistics",
      "mcp__rvt-mcp__revit_analyze_sheet_layout",
      "mcp__rvt-mcp__revit_analyze_structural_connections",
      "mcp__rvt-mcp__revit_analyze_usage_patterns",
      "mcp__rvt-mcp__revit_analyze_view_naming_patterns",
      "mcp__rvt-mcp__revit_audit_families",
      "mcp__rvt-mcp__revit_clash_detection",
      "mcp__rvt-mcp__revit_compute_element_area",
      "mcp__rvt-mcp__revit_compute_element_volume",
      "mcp__rvt-mcp__revit_detect_firm_profile",
      "mcp__rvt-mcp__revit_detect_system_elements",
      "mcp__rvt-mcp__revit_find_elements_in_volume",
      "mcp__rvt-mcp__revit_find_mep_disconnects",
      "mcp__rvt-mcp__revit_find_overlapping_elements",
      "mcp__rvt-mcp__revit_find_schedule_elements",
      "mcp__rvt-mcp__revit_find_undimensioned_elements",
      "mcp__rvt-mcp__revit_find_untagged_elements",
      "mcp__rvt-mcp__revit_get_assembly_members",
      "mcp__rvt-mcp__revit_get_available_family_types",
      "mcp__rvt-mcp__revit_get_change_records",
      "mcp__rvt-mcp__revit_get_current_target",
      "mcp__rvt-mcp__revit_get_current_view_info",
      "mcp__rvt-mcp__revit_get_element_bounding_box",
      "mcp__rvt-mcp__revit_get_element_centroid",
      "mcp__rvt-mcp__revit_get_element_details",
      "mcp__rvt-mcp__revit_get_element_geometry",
      "mcp__rvt-mcp__revit_get_element_parameters",
      "mcp__rvt-mcp__revit_get_element_relationships",
      "mcp__rvt-mcp__revit_get_family_instances",
      "mcp__rvt-mcp__revit_get_group_members",
      "mcp__rvt-mcp__revit_get_link_coordinate_system",
      "mcp__rvt-mcp__revit_get_link_elements",
      "mcp__rvt-mcp__revit_get_material_properties",
      "mcp__rvt-mcp__revit_get_material_quantities",
      "mcp__rvt-mcp__revit_get_mep_element_connectors",
      "mcp__rvt-mcp__revit_get_model_warnings_summary",
      "mcp__rvt-mcp__revit_get_panel_schedule",
      "mcp__rvt-mcp__revit_get_print_settings",
      "mcp__rvt-mcp__revit_get_project_coordinate_system",
      "mcp__rvt-mcp__revit_get_room_boundaries",
      "mcp__rvt-mcp__revit_get_room_openings",
      "mcp__rvt-mcp__revit_get_schedulable_fields",
      "mcp__rvt-mcp__revit_get_schedule_data",
      "mcp__rvt-mcp__revit_get_schedule_definition",
      "mcp__rvt-mcp__revit_get_schedule_formulas",
      "mcp__rvt-mcp__revit_get_selected_elements",
      "mcp__rvt-mcp__revit_get_structural_loads",
      "mcp__rvt-mcp__revit_get_system_inventory",
      "mcp__rvt-mcp__revit_get_titleblock_parameters",
      "mcp__rvt-mcp__revit_get_type_parameters",
      "mcp__rvt-mcp__revit_get_view_visibility",
      "mcp__rvt-mcp__revit_get_viewport_geometry",
      "mcp__rvt-mcp__revit_list_areas",
      "mcp__rvt-mcp__revit_list_assemblies",
      "mcp__rvt-mcp__revit_list_available_targets",
      "mcp__rvt-mcp__revit_list_baked_tools",
      "mcp__rvt-mcp__revit_list_export_settings",
      "mcp__rvt-mcp__revit_list_family_types_in_family",
      "mcp__rvt-mcp__revit_list_groups",
      "mcp__rvt-mcp__revit_list_keynotes",
      "mcp__rvt-mcp__revit_list_linked_cad",
      "mcp__rvt-mcp__revit_list_linked_models",
      "mcp__rvt-mcp__revit_list_loaded_families",
      "mcp__rvt-mcp__revit_list_materials",
      "mcp__rvt-mcp__revit_list_mep_systems",
      "mcp__rvt-mcp__revit_list_phases",
      "mcp__rvt-mcp__revit_list_project_parameter_bindings",
      "mcp__rvt-mcp__revit_list_project_parameters",
      "mcp__rvt-mcp__revit_list_rebar",
      "mcp__rvt-mcp__revit_list_recent_models",
      "mcp__rvt-mcp__revit_list_revisions",
      "mcp__rvt-mcp__revit_list_rooms",
      "mcp__rvt-mcp__revit_list_saved_selections",
      "mcp__rvt-mcp__revit_list_schedules",
      "mcp__rvt-mcp__revit_list_shared_parameters",
      "mcp__rvt-mcp__revit_list_sheets",
      "mcp__rvt-mcp__revit_list_titleblocks",
      "mcp__rvt-mcp__revit_list_view_filters",
      "mcp__rvt-mcp__revit_list_view_templates",
      "mcp__rvt-mcp__revit_list_worksets",
      "mcp__rvt-mcp__revit_load_selection",
      "mcp__rvt-mcp__revit_measure_distance_between_elements",
      "mcp__rvt-mcp__revit_project_point_onto_face",
      "mcp__rvt-mcp__revit_raycast_from_point",
      "mcp__rvt-mcp__revit_select_elements",
      "mcp__rvt-mcp__revit_show_element_in_view",
      "mcp__rvt-mcp__revit_show_message",
      "mcp__rvt-mcp__revit_suggest_view_name_corrections",
      "mcp__rvt-mcp__revit_survey_change_impact",
      "mcp__rvt-mcp__revit_workflow_model_audit"
    ]
  }
}

send_code defaults on, independently of ToolBaker; call-log defaults off. CLI overrides environment variables, which override JSON. Authenticated server settings override plugin settings for that request only. Call-log off suppresses the server journal, plugin mcp-calls.jsonl and send-code body journal; in-memory History remains available. Body journaling needs both call-log on and its separate TTL opt-in. ToolBaker usage.jsonl is separate and follows adaptive-bake settings.

The response guard defaults on: UTF-8 warnings at 65536 bytes, strong warnings above 262144, a 716800-byte budget and a 1048576-byte transport cap. JSON escaping and MCP content/metadata are measured at the server. Oversized reads return RESPONSE_TOO_LARGE with narrowing guidance; completed writes return a compact summary. Arbitrary code output spills to a local file with mutation_applied: null; inspect the file instead of rerunning the command. A spill file is kept 36 hours by default (--spill-retention-hours, 1-8760; an invalid value uses 36) and no file-count cap deletes a younger file. Turning the guard off leaves the transport cap active. Byte limits must be integers >=1024, ordered warn <= strong <= budget <= max; adjust lower thresholds when lowering the budget.

Supported Revit versions

Full Revit desktop only; Revit Viewer is not a supported target. CI builds all six add-ins, but runtime depth varies by year — recheck baked tools and custom C# on the years you use.

Multiple Revit instances

The server binds to exactly one Revit instance — including when several instances of the same year run at once. It binds implicitly on the first call or explicitly through --target / BIMWRIGHT_TARGET / revit_switch_target. Selectors: auto, a 4-digit year (2024), pid:<n> or id:revit-<year>-<pid>; legacy R-codes like R24 are rejected.

When more than one instance runs — especially several of the same year — do not guess the target:

1. Call revit_list_available_targets: every live instance is listed with target_id, pid, host_year, window_title and source.

2. Pick the instance by pid and/or window_title.

3. Pin it with revit_switch_target("pid:<n>") — any selector form works, pid: is unambiguous.

4. revit_get_current_target shows the active binding, its generation and the proposed next_target_id.

Target error codes and how to react. Every code except TARGET_INTERRUPTED means the command was not sent:

After a Revit restart — even with a single Revit open — the next call returns TARGET_CHANGED and the server waits for one revit_switch_target call before it sends anything. This is deliberate: the restarted Revit can have a different model open, so the server never rebinds to it silently. The payload names the proposed instance; confirm it and repeat the call.

revit_switch_target is annotated non-read-only because it changes session routing, but it stays available under --read-only so the binding can always be recovered.

Security and privacy

• Local by default: loopback TCP or a local named pipe, with a per-session auth token in the discovery files under %LOCALAPPDATA%\Bimwright\rvt-mcp\.

• Tool arguments are schema-checked before handlers run; errors returned to the model are sanitized.

• send_code runs arbitrary C# in the Revit process — powerful and risky. Use --read-only or --disable-send-code if that is unacceptable.

• Adaptive bake, body cache and send_code journals are opt-in and stay under your user profile; defaults do not write raw send_code bodies to long-lived logs.

More: SECURITY.md, docs/bake.md.

Docs

Community contributions

Code, bug reports, reproducible examples and proposals help improve rvt-mcp. Thanks to:

The bimwright family

Open-source tools connecting AI assistants to BIM and CAD applications.

The name bimwright combines BIM with wright, an old word for a maker or builder—as in shipwright.

See how the gateway names are chosen.

• rvt-mcp — Autodesk® Revit®

• dwg-mcp — Autodesk® AutoCAD®

• nwd-mcp — Autodesk® Navisworks®

• ipt-mcp — Autodesk® Inventor®

• bim-wiki — Vietnamese-first BIM knowledge base

License

Apache-2.0 — LICENSE.

Forks and rebrands are welcome — the license terms are all that's required (keep LICENSE and the copyright notices, mark changed files). If rvt-mcp helped you, a star or a mention of BIMwright in your product is appreciated but entirely optional. Issues and PRs are always welcome.

Revit and Autodesk are trademarks of Autodesk, Inc. bimwright is an independent open-source project and is not affiliated with, sponsored by, or endorsed by Autodesk, Inc.