---

What Is This?

Civil3D-MCP bridges AI assistants (Claude, Cline, Cursor, etc.) to a live, open Civil 3D drawing using the Model Context Protocol. Give Claude your design brief — it reads your drawing, runs calculations, and makes changes in real time.

MCP client  <-- stdio ----------->  civil3d-mcp (Node.js)
HTTP client <-- HTTP :3000 ------>  civil3d-mcp (Node.js)
civil3d-mcp <-- JSON-RPC/TCP :8080 --> Civil3DMcpPlugin.dll --> Civil 3D 2026 API

This is the MCP server (TypeScript). You also need the Civil 3D .NET plugin — see Installation.

What Changed Recently

• Production-ready host execution now includes bounded queues and jobs,
  cancellation, idempotency, structured telemetry, readiness endpoints, and
  observable rotating plugin logs.
• New: civil3d_help searches the locally installed Autodesk Civil 3D help,
  returns cited topics with screenshots, and surfaces matching tutorial videos in chat.
• The default MCP surface is compact: 34 public tools cover every domain. The
  complete 219-tool surface can be enabled when a client needs specialized aliases.
• Native workflow handlers cover major QC, grading, hydrology, plan-production,
  and data-shortcut flows instead of relying only on client-side orchestration.
• Claude Code can be registered with a single project-scoped command that
  installs dependencies, builds the Node server, and writes the repo .mcp.json entry.
• Claude Desktop now has a self-contained MCPB installer plus a legacy DXT
  compatibility artifact, generated with npm run package:claude.
• The release-checked inventory is generated from the runtime manifest at
  docs/tools.generated.md.

---

Autodesk Help in Chat

Agents can now answer Civil 3D how-to questions from the Autodesk Offline Help
installed on the user's machine. The civil3d_help tool auto-discovers Civil 3D
help under Program Files, builds a local search index, and returns:

• cleaned, version-matched Autodesk topic text with a canonical citation;
• useful screenshots and diagrams directly in the chat response;
• the best matching Autodesk tutorial video as a player resource;
• a direct MP4 link when the chat client cannot embed the player.

For example, an agent can search for grading guidance:

{
  "action": "search",
  "query": "how do I create grading criteria?",
  "version": "2026"
}

Or request only matching videos:

{
  "action": "search_videos",
  "query": "create grading criteria",
  "maxVideos": 2
}

The bundled 2026 catalog currently contains 47 Civil 3D tutorial videos. See the
Autodesk grading-criteria video
for an example. Topic and image retrieval remains local and works without the
Civil 3D drawing plugin; Autodesk-hosted video playback requires internet access.

The first topic query creates a compressed cache under
%LOCALAPPDATA%\Civil3DMcp\help-index. Later queries reuse that cache and full
topic retrieval is effectively immediate. See Local Autodesk help search
for configuration and additional examples.

---

Quick Start

If you want the fastest path from clone to a working Claude + Civil 3D setup on Windows:

For Claude Desktop, a release .mcpb is the easiest Node-side installation:

1. Open Settings > Extensions > Advanced settings > Install Extension.
2. Select civil3d-mcp-<version>.mcpb and keep ports 8080 and 3000 unless
   your local setup uses different ports.
3. Open Civil 3D and load the native plugin with NETLOAD or the APPLOAD
   Startup Suite.
4. Ask Claude to run civil3d_health.

The extension installs the Node MCP server and its production dependencies. It
does not install the native Autodesk plugin. Maintainers can build both the
current .mcpb and legacy .dxt files with:

npm install
npm run package:claude

For a source-based or Claude Code installation:

1. Clone and build the Node side:

   git clone https://github.com/Sacred-G/Civil3D-mcp.git
   cd Civil3D-mcp
   npm install
   npm run build
   

2. Build and NETLOAD the Civil 3D plugin:

   dotnet build .\Civil3D-MCP-Plugin\Civil3DMcpPlugin.csproj -c Release `
     /p:Civil3DReferencesPath="C:\Program Files\Autodesk\AutoCAD 2026\C3D"
   

3. Register Claude Code for this repo:

   npm run claude:add
   

4. Open Civil 3D, load the plugin, and start asking for real work:

   • "Audit this drawing before design starts."
   • "Create a grading surface from this feature line."
   • "Delineate the watershed and estimate runoff."
   • "Publish the plan/profile sheets to PDF."

---

Features

• Compact default MCP surface with 34 public tools; all 219 registered
  routes remain internally callable or available as opt-in aliases
• Local Autodesk help in chat — version-matched topics, screenshots,
  diagrams, citations, and playable Civil 3D tutorial videos
• Native workflow execution for corridor QC, surface comparison, project startup, grading conversion, plan publish, data shortcuts, and hydrology pipelines
• Full road design pipeline — alignments, profiles, corridors, cross-sections, superelevation
• Surface analysis — elevation bands, slope distribution, aspect, watershed, cut/fill volumes
• Pipe & pressure network design, validation, and hydraulic analysis
• Plan production — sheet sets, Plan/Profile sheets, PDF export
• QC checks — alignment, profile, corridor, surface, pipe network, drawing standards
• Quantity takeoff — earthwork, corridor materials, pipe lengths, parcel areas, CSV export
• Cost estimation — pay items, material costs, construction estimates
• Hydrology — flow path tracing, watershed delineation, Rational Method runoff, time of concentration
• Grading — feature lines, grading groups, grading criteria, surface generation
• COGO/Survey — inverse, traverse, curve solve, survey figures, LandXML import
• Storm & Sanitary Analysis (SSA) integration and detention basin sizing
• Intersection design and corridor target mapping
• Sight distance calculations and AASHTO stopping sight distance checks
• Assembly/subassembly creation and editing

Protected action flow

Destructive, file-writing, import/export, and other non-retryable drawing
mutations use a three-step policy flow:

1. Call civil3d_preview_action with the target toolName, action, and the
   exact parameters to validate the operation and learn whether approval is required.
2. If required, call civil3d_request_approval with the same values. It issues
   a short-lived, single-use token bound to the active drawing and those exact parameters.
3. Retry the target tool call with approvalToken. Changing the drawing,
   action, or parameters invalidates the token.

Set CIVIL3D_APPROVAL_MODE=disabled only for isolated local development or
test environments; production deployments should retain the default policy.

Canonical tools and aliases

Aliases do not unlock extra Civil 3D capabilities. They are narrower convenience
names for actions already available through a canonical domain tool.

Surface	Exposed tools	How to call an operation
Default MCP client	34	Call a canonical domain tool and provide action.
MCP client with aliases enabled	219	Use either canonical tools or specialized alias names.
HTTP /execute and orchestration	219	All registered routes remain internally callable in either mode.

For example, these calls are equivalent:

{
  "tool": "civil3d_surface",
  "parameters": {
    "action": "volume_calculate",
    "baseSurface": "Existing Ground",
    "comparisonSurface": "Finished Grade"
  }
}

{
  "tool": "civil3d_surface_volume_calculate",
  "parameters": {
    "baseSurface": "Existing Ground",
    "comparisonSurface": "Finished Grade"
  }
}

The compact default is recommended because it gives the model fewer overlapping
tool descriptions while preserving every operation. To expose all specialized
aliases, set this variable in the environment that starts the MCP server, then
restart the client connection:

$env:CIVIL3D_ENABLE_TOOL_ALIASES = "true"
npm run start

For a client-managed server, put the variable in its MCP configuration:

{
  "mcpServers": {
    "civil3d-mcp": {
      "command": "node",
      "args": ["C:/path/to/civil3d-mcp/build/index.js"],
      "env": {
        "CIVIL3D_ENABLE_TOOL_ALIASES": "true"
      }
    }
  }
}

Discover operations through the civil3d://catalog/tools MCP resource or
docs/tools.generated.md. Canonical rows list
their supported actions; alias rows provide the corresponding convenience name.
Approval requirements are identical for canonical and alias calls.

---

Architecture

flowchart LR
    Client["MCP Client\n(Claude / Cline / Cursor)"] <-->|"MCP stdio"| Server["civil3d-mcp\nNode.js"]
    HttpClient["Local HTTP Client"] -->|"HTTP :3000"| Server
    Server <-->|"JSON-RPC/TCP :8080"| Plugin

    subgraph Civil3D ["Autodesk Civil 3D"]
        Plugin["Civil3DMcpPlugin.dll\nTCP Listener"]
        Queue["Bounded Host Queue"]
        Context["ExecuteInCommandContextAsync"]
        Safety["Document Lock + Transaction"]
        API["Civil 3D 2026 .NET API"]

        Plugin --> Queue --> Context --> Safety --> API
    end

Civil 3D database operations execute inside Autodesk command context under a
bounded, serialized host gate. Mutations additionally use a document lock and a
narrow transaction; callers never mutate a drawing directly from Node.js.

---

Requirements

Component	Version
Node.js	18+
Civil 3D	2026 (live validated)
.NET SDK	8.0
Civil 3D API refs	Licensed local installation or untracked reference directory
Visual Studio	2022 recommended

---

Installation

1 — Build the MCP Server (TypeScript)

git clone https://github.com/Sacred-G/Civil3D-mcp.git
cd Civil3D-mcp
npm install
npm run build

1.5 — One-Line Claude Code Setup

From the repo root on Windows, this project-scoped command adds the MCP server to Claude Code and creates the repo .mcp.json entry automatically:

claude mcp add --scope project --transport stdio civil3d-mcp -- powershell -NoProfile -ExecutionPolicy Bypass -File "$PWD\scripts\claude-bootstrap-and-run.ps1"

The registered launcher will automatically install npm dependencies and build the Node server the first time Claude starts it.

If you want a wrapper that does the install, build, and claude mcp add step for you immediately, run:

npm run claude:add

Useful variants:

npm run claude:add:user
npm run claude:print-add

1.6 — Claude Desktop Extension Package

Current Claude Desktop releases install MCP extensions from .mcpb files. The
former DXT format was renamed to MCPB, so the packaging command also emits a
byte-for-byte .dxt compatibility copy for older releases:

npm run package:claude

Generated files are written to dist/claude-desktop/ and include SHA-256
checksums. Install the .mcpb from Claude Desktop > Settings > Extensions >
Advanced settings > Install Extension. The package exposes installer fields
for the Civil 3D host and plugin port, alias mode, log level, and the local HTTP
bridge port (default 3000).

2 — Build & Load the C# Plugin

Prerequisites: Civil 3D 2026, .NET 8 SDK, and licensed local Civil 3D managed
API assemblies. Autodesk binaries are intentionally not tracked or published by
this repository.

$refs = "C:\Program Files\Autodesk\AutoCAD 2026\C3D"
dotnet build .\Civil3D-MCP-Plugin\Civil3DMcpPlugin.csproj -c Release `
  /p:Civil3DReferencesPath="$refs"
# Output: Civil3D-MCP-Plugin\bin\Release\net8.0-windows\Civil3DMcpPlugin.dll

An untracked C_References directory remains the local fallback when
Civil3DReferencesPath is omitted.

At minimum, the configured directory must contain:

accoremgd.dll
AcDbMgd.dll
acmgd.dll
AecBaseMgd.dll
AeccDbMgd.dll
AeccPressurePipesMgd.dll

Load into Civil 3D:

Method	Steps
Manual (NETLOAD)	Open Civil 3D → type NETLOAD → browse to Civil3D-MCP-Plugin.dll
Autoload (recommended)	Add registry key — see DEPLOYMENT.md

Once loaded, three commands are available in the Civil 3D command line:

Command	Description
C3DMCPSTART	Start the JSON-RPC server (auto-starts on plugin load)
C3DMCPSTOP	Stop the JSON-RPC server
C3DMCPSTATUS	Show server status, port, and queue depth

3 — Configure Your AI Client

Recommended for Claude Code

npm run claude:add

That command registers the bootstrap launcher in Claude Code and keeps the repo self-contained. Use npm run claude:print-add if you want to inspect the exact claude mcp add command without modifying config.

Claude Desktop — install the generated .mcpb package. For source-based
development, claude_desktop_config.json remains supported:

{
  "mcpServers": {
    "civil3d-mcp": {
      "command": "node",
      "args": ["C:/path/to/Civil3D-mcp/build/index.js"]
    }
  }
}

Claude Code — add via CLI:

claude mcp add --scope project --transport stdio civil3d-mcp -- powershell -NoProfile -ExecutionPolicy Bypass -File "$PWD\scripts\claude-bootstrap-and-run.ps1"

Restart your client. When you see the hammer icon, the MCP connection is live.

For Docker, npm publishing, environment variables, and alternate deployment paths see docs/DEPLOYMENT.md.

---

Example Conversations

"What alignments are in this drawing and how long is each one?"
→ civil3d_alignment → returns names, station ranges, lengths

"Run a full QC check on the corridor and give me a report."
→ civil3d_workflow with action: "corridor_qc_report"

"Trace the flow path from coordinate (5000, 3200) and estimate the peak runoff using the Rational Method."
→ civil3d_hydrology with action: "watershed_runoff_workflow"

"Publish the existing Plan Production sheet set to PDF."
→ civil3d_workflow with action: "plan_production_publish"

"Size the storm drain network for a 10-year storm and check all pipe velocities."
→ civil3d_pipe with action: "size_network", then action: "hydraulic_analysis"

"Calculate cut/fill volumes between the existing ground and proposed surface."
→ civil3d_surface with action: "volume_calculate", then action: "volume_report"

---

Tool Reference (217 catalog entries)

The generated, release-checked inventory is docs/tools.generated.md.
It includes both canonical tools and specialized aliases. Canonical rows list
one or more operations; alias rows show an em dash in the Operations column.

Drawing Info & Context (7 tools)

Tool	Description
get_drawing_info	Retrieves basic information about the active Civil 3D drawing
list_civil_object_types	Lists major Civil 3D object types present in the current drawing
get_selected_civil_objects_info	Gets properties of currently selected Civil 3D objects
civil3d_health	Reports Civil 3D connection and plugin status
civil3d_drawing	Manages drawing state, document info, save/undo operations
civil3d_job	Checks status of long-running async operations or requests cancellation
list_tool_capabilities	Lists domain and capability metadata for the full MCP tool catalog

Drawing Primitives (6 tools)

Tool	Description
create_cogo_point	Creates a single COGO point
create_line_segment	Creates a simple line segment
acad_create_polyline	Creates an AutoCAD 2D polyline in model space
acad_create_3dpolyline	Creates an AutoCAD 3D polyline in model space
acad_create_text	Creates AutoCAD DBText in model space
acad_create_mtext	Creates AutoCAD MText in model space

Alignment (9 tools)

Tool	Description
civil3d_alignment	Reads alignments, converts stationing, create/delete
civil3d_alignment_report	Builds structured alignment geometry report
civil3d_alignment_get_station_offset	Returns station/offset of an XY point relative to an alignment
civil3d_alignment_add_tangent	Appends a fixed tangent entity to an alignment
civil3d_alignment_add_spiral	Appends a spiral (transition curve) to an alignment
civil3d_alignment_delete_entity	Deletes a tangent/curve/spiral entity by index
civil3d_alignment_offset_create	Creates a new offset alignment at a constant distance
civil3d_alignment_set_station_equation	Adds a station equation to an alignment
civil3d_alignment_widen_transition	Creates a variable-offset widening/narrowing transition region

Profile (10 tools)

Tool	Description
civil3d_profile	Reads profiles, create/delete
civil3d_profile_report	Builds structured profile report with station/elevation sampling
civil3d_profile_get_elevation	Samples elevation and grade at a given station
civil3d_profile_add_pvi	Adds a PVI to a layout profile
civil3d_profile_add_curve	Adds a parabolic vertical curve at an existing PVI
civil3d_profile_delete_pvi	Deletes the PVI nearest to a specified station
civil3d_profile_set_grade	Sets the grade of a tangent entity
civil3d_profile_check_k_values	Validates K-values against AASHTO minimums for design speed
civil3d_profile_view_create	Creates a profile view at a specified insertion point
civil3d_profile_view_band_set	Applies a band set style to an existing profile view

Superelevation (4 tools)

Tool	Description
civil3d_superelevation_get	Retrieve superelevation design data for an alignment
civil3d_superelevation_set	Apply superelevation using AASHTO attainment method
civil3d_superelevation_design_check	Validate max superelevation rates and attainment lengths
civil3d_superelevation_report	Generate formatted superelevation report

Surface (15 tools)

Tool	Description
civil3d_surface	Reads surface data, create/delete
civil3d_surface_edit	Modifies surface data: points, breaklines, boundaries, contours
civil3d_surface_statistics_get	Comprehensive statistics: elevation range, area, point/triangle count
civil3d_surface_contour_interval_set	Set minor and major contour display intervals
civil3d_surface_sample_elevations	Sample elevations at grid points, discrete points, or transect
civil3d_surface_analyze_elevation	Elevation band distribution (area and percentage per band)
civil3d_surface_analyze_slope	Slope distribution (area and percentage per slope range)
civil3d_surface_analyze_directions	Aspect/facing direction breakdown by cardinal sectors
civil3d_surface_volume_calculate	Calculate cut/fill volumes between two surfaces
civil3d_surface_volume_by_region	Cut/fill volumes within a polygon region
civil3d_surface_volume_report	Formatted human-readable cut/fill volume report
civil3d_surface_comparison_workflow	Structured two-surface comparison with cut/fill volumes
civil3d_surface_create_from_dem	Create TIN surface from DEM file (.dem, .tif, .asc, .flt)
civil3d_surface_watershed_add	Add watershed analysis: drainage basins and flow paths
civil3d_surface_drainage_workflow	Surface drainage workflow: flow path, elevation sampling, runoff estimate

Corridor (6 tools)

Tool	Description
civil3d_corridor	Reads corridor data, rebuild, volume operations
civil3d_corridor_summary	Builds corridor summary with surfaces and volume analysis
civil3d_corridor_target_mapping_get	Retrieve subassembly target mappings for a corridor
civil3d_corridor_target_mapping_set	Set/update subassembly target mappings (surfaces, alignments, profiles)
civil3d_corridor_region_add	Add a new region to a corridor baseline
civil3d_corridor_region_delete	Delete a region from a corridor baseline

Sections & Section Views (6 tools)

Tool	Description
civil3d_section	Reads section data, sample line creation
civil3d_section_view_create	Create section views for a sample line group
civil3d_section_view_list	List section views in the drawing
civil3d_section_view_update_style	Update display/band set style on existing section views
civil3d_section_view_group_create	Create section views using the drawing's draft-placement settings
civil3d_section_view_export	Export section station, source, offset, and elevation data to CSV

Intersection Design (2 tools)

Tool	Description
civil3d_intersection_list	List all intersections in the drawing
civil3d_intersection_get	Get detailed properties of an intersection

Grading & Feature Lines (14 tools)

Tool	Description
civil3d_grading	Canonical grading domain tool for groups, gradings, criteria, and feature-line actions
civil3d_feature_line	Reads feature lines and exports them as 3D polylines
civil3d_feature_line_create	Create a new feature line from 3D points
civil3d_grading_group_list	List all grading groups in the drawing
civil3d_grading_group_create	Create a new grading group
civil3d_grading_group_get	Get detailed info about a grading group
civil3d_grading_group_delete	Delete a grading group and all its gradings
civil3d_grading_group_volume	Get cut/fill volume report for a grading group
civil3d_grading_group_surface_create	Create a surface from a grading group
civil3d_grading_criteria_list	List all available grading criteria sets
civil3d_grading_list	List all grading objects within a grading group
civil3d_grading_create	Create a new grading from a feature line
civil3d_grading_get	Get detailed properties of a grading object
civil3d_grading_delete	Delete a grading object by handle

Points & Point Groups (6 tools)

Tool	Description
civil3d_point	Reads, creates, imports, deletes COGO points and point groups
civil3d_point_export	Export COGO points to text/CSV (PNEZD, PENZ, XYZD, XYZ, CSV)
civil3d_point_transform	Transform points by translation, rotation, and/or scale
civil3d_point_group_create	Create a new point group with filter criteria
civil3d_point_group_update	Update filter criteria and description of a point group
civil3d_point_group_delete	Delete a point group (points are NOT deleted)

COGO & Survey (8 tools)

Tool	Description
civil3d_cogo_inverse	Calculate bearing and distance between two coordinate pairs
civil3d_cogo_direction_distance	Project a point from start coordinate given bearing and distance
civil3d_cogo_curve_solve	Solve a horizontal curve given any two curve elements
civil3d_cogo_traverse	Solve a traverse from start point through bearing/distance courses
civil3d_coordinate_system	Coordinate system info and coordinate transformations
civil3d_survey_database_list	List all survey databases
civil3d_survey_figure_list	List all survey figures
civil3d_survey_figure_get	Get 3D vertex data for a specific survey figure

Pipe Networks — Gravity (3 tools)

Tool	Description
civil3d_pipe_catalog	Lists available pipe parts lists and part names
civil3d_pipe_network	Reads pipe network data: networks, pipes, structures
civil3d_pipe_network_edit	Creates and modifies pipe networks, pipes, and structures

Pressure Networks (15 tools)

Tool	Description
civil3d_pressure_network_list	List all pressure networks
civil3d_pressure_network_create	Create a new pressure network
civil3d_pressure_network_get_info	Get detailed info about a pressure network
civil3d_pressure_network_delete	Delete a pressure network and all components
civil3d_pressure_network_assign_parts_list	Assign a parts list to a network
civil3d_pressure_network_set_cover	Set minimum cover depth for pipes in a network
civil3d_pressure_network_validate	Validate a network for cover violations and disconnections
civil3d_pressure_network_export	Export pressure network data as structured JSON
civil3d_pressure_network_connect	Connect two pressure networks by merging
civil3d_pressure_pipe_add	Add a pressure pipe segment
civil3d_pressure_pipe_get_properties	Get properties of a pressure pipe
civil3d_pressure_pipe_resize	Change pressure pipe size to a different catalog entry
civil3d_pressure_fitting_add	Add a pressure fitting (elbow, tee, reducer, cap)
civil3d_pressure_fitting_get_properties	Get properties of a pressure fitting
civil3d_pressure_appurtenance_add	Add a pressure appurtenance (valve, hydrant, meter)

Plan Production / Sheets (11 tools)

Tool	Description
civil3d_sheet_set_list	List all Plan Production sheet sets
civil3d_sheet_set_create	Create a new Plan Production sheet set
civil3d_sheet_set_get_info	Get detailed info about a sheet set
civil3d_sheet_set_export	Export all sheets to a multi-page PDF
civil3d_sheet_set_title_block	Set or update title block template on a sheet
civil3d_sheet_add	Add a new sheet to an existing sheet set
civil3d_sheet_get_properties	Get full properties of a specific sheet
civil3d_sheet_publish_pdf	Publish sheet layouts to a PDF file
civil3d_sheet_view_create	Create a viewport/view on a sheet layout
civil3d_sheet_view_set_scale	Update the scale of a viewport
civil3d_plan_profile_sheet_update_alignment	Update alignment and/or profile on an existing sheet

QC Checks (8 tools)

Tool	Description
civil3d_qc_check_alignment	QC alignment: tangent lengths, curve radii, spirals, design-speed compliance
civil3d_qc_check_profile	QC profile: max grade, K-values, sight distance requirements
civil3d_qc_check_corridor	QC corridor: invalid regions, missing targets, assembly gaps, rebuild errors
civil3d_qc_check_pipe_network	QC pipe network: cover depth, slope, velocity, connectivity
civil3d_qc_check_surface	QC TIN surface: elevation spikes, flat triangles, crossing breaklines
civil3d_qc_check_labels	Check labels for missing labels and style standard violations
civil3d_qc_check_drawing_standards	Audit drawing: layer naming, lineweights, colors
civil3d_qc_report_generate	Run full QC pass and write consolidated report to disk

Workflow Automation (13 tools)

Tool	Description
civil3d_workflow	Canonical workflow tool for multi-step QC, grading, pipe-design, standards, and publishing
civil3d_workflow_corridor_qc_report	Run corridor QC and optionally generate a consolidated QC report
civil3d_workflow_grading_surface_volume	Calculate grading cut/fill volume between base and comparison surfaces
civil3d_workflow_surface_comparison_report	Run a structured surface comparison and follow it with a volume report
civil3d_workflow_data_shortcut_publish_sync	Publish a data shortcut and immediately synchronize it
civil3d_workflow_data_shortcut_reference_sync	Reference a project data shortcut and immediately synchronize it
civil3d_workflow_project_startup	Check Civil 3D health, inspect drawing readiness, and optionally create/save a startup drawing
civil3d_workflow_project_reference_setup	Reference one or more project data shortcuts, sync them, and optionally save
civil3d_workflow_drawing_readiness_audit	Check health, drawing state, selection context, and standards readiness in one audit
civil3d_workflow_feature_line_to_grading	Convert a feature line into grading and optionally create a grading surface
civil3d_workflow_pipe_network_design	Size a gravity pipe network and optionally run hydraulic analysis
civil3d_workflow_plan_production_publish	Publish a sheet set or explicit layout list to PDF output
civil3d_workflow_qc_fix_and_verify	Audit drawing standards, apply fixes, and verify the result

Quantity Takeoff (8 tools)

Tool	Description
civil3d_qty_surface_volume	Cut/fill volumes between surfaces (with corridor or region scope)
civil3d_qty_earthwork_summary	Running earthwork cut/fill summary table
civil3d_qty_pipe_network_lengths	Total pipe lengths for a gravity pipe network
civil3d_qty_pressure_network_lengths	Total pipe lengths for a pressure network
civil3d_qty_alignment_lengths	Total length for one or more alignments
civil3d_qty_parcel_areas	Area, perimeter, and address data for parcels
civil3d_qty_point_count_by_group	Count COGO points per point group
civil3d_qty_export_to_csv	Export consolidated quantity takeoff report to CSV

Hydrology (7 tools)

Tool	Description
civil3d_hydrology	Canonical hydrology tool for surface drainage, catchments, Tc, SSA, and multi-step workflows
civil3d_catchment	Manages catchments and catchment groups, including properties, flow paths, and boundaries
civil3d_time_of_concentration	Calculates Tc using supported methods and generates hydrographs
civil3d_stm	Opens interactive STM import/export and Storm and Sanitary Analysis dialogs
civil3d_hydrology_watershed_runoff_workflow	Runs low-point or outlet-based watershed delineation through runoff estimation
civil3d_hydrology_runoff_detention_workflow	Runs runoff estimation through detention sizing and optional stage-storage output
civil3d_hydrology_runoff_pipe_workflow	Runs runoff estimation through gravity pipe HGL and hydraulic analysis

Pipe Hydraulics (3 tools)

Tool	Description
civil3d_pipe_network_hgl	Calculate Hydraulic Grade Line (HGL) for gravity pipe networks
civil3d_pipe_network_hydraulics	Perform full hydraulic capacity analysis on pipe networks
civil3d_pipe_structure_properties	Retrieve detailed properties of individual pipe structures

Pipe Design Automation (2 tools)

Tool	Description
civil3d_pipe_network_size	Size gravity-network pipes from Manning full-flow capacity with catalog part selection
civil3d_pipe_profile_view_automation	Automate gravity-pipe profile-view setup with EG profile creation

Assembly Creation (3 tools)

Tool	Description
civil3d_assembly_create	Create a new Civil 3D assembly at a specified model-space location
civil3d_subassembly_create	Add a subassembly from the Civil 3D catalog to an existing assembly
civil3d_assembly_edit	Inspect or modify an existing Civil 3D assembly (list, update, delete subassemblies)

Sight Distance (2 tools)

Tool	Description
civil3d_sight_distance_calculate	Calculate AASHTO stopping, passing, or decision sight distance for design speed
civil3d_stopping_distance_check	Check stopping sight distance compliance along an alignment at station intervals

Detention & Stormwater (2 tools)

Tool	Description
civil3d_detention_basin_size_calculate	Size a detention basin to reduce peak stormwater runoff
civil3d_detention_stage_storage	Generate stage-storage-discharge table for a detention basin surface

Slope Analysis (1 tool)

Tool	Description
civil3d_slope_geometry_calculate	Calculate daylight line coordinates and slope geometry for cut/fill sections

Cost Estimation (2 tools)

Tool	Description
civil3d_pay_items_export	Extract Civil 3D quantities and export as structured pay item schedule to CSV/Excel
civil3d_material_cost_estimate	Generate construction cost estimate by combining quantities with unit prices

Survey Processing (1 tool)

Tool	Description
civil3d_survey_observation_list	List survey observations from a survey database

Data Shortcuts (4 tools)

Tool	Description
civil3d_data_shortcut_create	Create data shortcuts for Civil 3D objects
civil3d_data_shortcut_promote	Promote data shortcut references to full editable objects
civil3d_data_shortcut_reference	Reference existing data shortcuts into the current drawing
civil3d_data_shortcut_sync	Synchronize outdated data shortcut references

Parcel Editing (4 tools)

Tool	Description
civil3d_parcel_create	Create parcels from polylines, feature lines, or vertex lists
civil3d_parcel_edit	Edit parcel properties (name, style, label style, description)
civil3d_parcel_lot_line_adjust	Adjust lot lines to achieve a target area
civil3d_parcel_report	Generate parcel reports with coordinate and unit settings

Standards & Miscellaneous (7 tools)

Tool	Description
civil3d_standards_lookup	Looks up Civil 3D standards, template governance, layer/style guidance, and labeling conventions
civil3d_assembly	Lists and inspects assemblies and subassemblies
civil3d_label	Manages labels on Civil 3D objects
civil3d_style	Lists and inspects Civil 3D styles
civil3d_parcel	Reads parcel and site data
civil3d_data_shortcut	Manages data shortcuts: listing, syncing, creating references
civil3d_orchestrate	Routes natural-language Civil 3D requests to the best tool

---

Civil 3D Version Compatibility

Civil 3D Version	Status	Notes
2023	Not currently validated	Requires a separate compatibility review and a build against matching licensed assemblies.
2024	Not currently validated	Requires a separate compatibility review and a build against matching licensed assemblies.
2025	Not currently validated	Requires a separate compatibility review and a build against matching licensed assemblies.
2026	Supported and live validated	Set Civil3DReferencesPath to the matching licensed 2026 managed assemblies.

For startup-suite and autoload registry details, use the version-specific guidance in docs/DEPLOYMENT.md.

---

Environment Variables

The Node MCP server reads the following variables at startup. All are optional; defaults are shown in the Default column and are suitable for a local Civil 3D plus Copilot install.

Plugin connection (Node → Civil 3D plugin)

Variable	Default	Purpose
CIVIL3D_HOST	localhost	Host the Civil 3D plugin's JSON-RPC TCP server binds to.
CIVIL3D_PORT	8080	TCP port the plugin listens on (see PluginRuntime.Port).
CIVIL3D_CONNECT_TIMEOUT	5000	Milliseconds the server waits for a TCP connection to the plugin before giving up.
CIVIL3D_COMMAND_TIMEOUT	120000	Milliseconds any single JSON-RPC command may run before the Node side rejects the call. Increase for heavy corridor rebuilds.
CIVIL3D_MAX_RESPONSE_BYTES	8388608	Maximum buffered response size accepted from the Civil 3D plugin.
CIVIL3D_LOG_LEVEL	info	One of debug, info, warn, error. Logs are written to stderr.

MCP tool surface and policy

Variable	Default	Purpose
CIVIL3D_ENABLE_TOOL_ALIASES	false	Set to true before the MCP server starts to expose all specialized aliases instead of the compact 34-tool surface.
CIVIL3D_APPROVAL_MODE	enforced	Set to disabled only in an isolated disposable test environment; production should retain parameter-bound approvals.

Local Autodesk help search

civil3d_help indexes the Autodesk Offline Help already installed with Civil 3D. It can search engineer phrasing such as “balance cut and fill” or “grading optimization,” return a cleaned Markdown topic, and attach the topic's useful screenshots and diagrams as MCP image content and civil3d://help/images/... resources. Matching Autodesk tutorial videos are returned as playable civil3d://help/videos/... player resources plus direct MP4 links. Decorative navigation icons are excluded. The drawing plugin does not need to be running for help searches.

The first query builds a compressed local index under %LOCALAPPDATA%\Civil3DMcp\help-index; later starts reuse it until the Autodesk help files change. By default the server discovers folders named Offline Help for Civil 3D <year> - <language>\Help under Program Files and prefers 2026.

Variable	Default	Purpose
CIVIL3D_HELP_ROOT	Auto-discovered	Optional absolute path to a Civil 3D Offline Help Help folder.
CIVIL3D_HELP_VERSION	2026	Preferred installed documentation version.
CIVIL3D_HELP_CACHE_ROOT	Local AppData	Override the generated search-index directory.
CIVIL3D_ENABLE_HELP_REINDEX	false	Set to true to allow the tool's explicit reindex action. Automatic cache refresh remains enabled.
CIVIL3D_HELP_MAX_IMAGE_BYTES	6291456	Maximum total bytes of inline image content returned by one topic request.
CIVIL3D_VIDEO_CATALOG	Bundled 2026 catalog	Optional path to a refreshed JSON catalog produced by scripts/scrape_autodesk_videos.py.

The normal search and get_topic actions include the best matching video by default. Use includeVideos: false to suppress it, maxVideos to change the limit, or search_videos for a video-only lookup. Autodesk hosts these Civil 3D videos online, so playback requires internet access even though topic and image search remains local.

Example calls:

{ "action": "search", "query": "how do I use grading optimization?", "version": "2026" }

{ "action": "get_topic", "id": "<id from search>", "version": "2026", "includeImages": true }

{ "action": "search_videos", "query": "create grading criteria", "maxVideos": 2 }

HTTP bridge (Copilot / local HTTP clients → Node)

Variable	Default	Purpose
MCP_HTTP_HOST	127.0.0.1	Interface the HTTP bridge binds to. Keep this on loopback unless you know what you're doing.
MCP_HTTP_PORT	3000	Port the HTTP bridge listens on.
MCP_HTTP_TOKEN	(unset)	Optional shared secret. When set, every request to the bridge must include Authorization: Bearer <token> or X-MCP-Token: <token>. Leave unset to keep the loopback-only open mode.
MCP_HTTP_MAX_BODY_BYTES	1048576	Maximum accepted POST /execute body size in bytes. Requests exceeding this receive 413 Payload Too Large.
MCP_HTTP_ALLOWED_ORIGINS	(unset)	Comma-separated browser origins allowed to call the bridge. Requests without an Origin header, such as native clients, are unaffected.
MCP_HTTP_ALLOWED_HOSTS	Loopback hostnames	Comma-separated HTTP Host names accepted by the bridge. Required with MCP_HTTP_TOKEN for non-loopback binds. Ports are ignored during comparison.

The bridge refuses to start on a non-loopback host unless MCP_HTTP_TOKEN is
configured. Docker Compose also requires this token and publishes the bridge on
the host loopback interface by default.

Plugin filesystem boundaries

Set these variables in the environment that launches Civil 3D. Roots are
semicolon-separated on Windows; every caller-supplied path is canonicalized and
must stay beneath an allowed root. If no roots are configured, the plugin uses
the current user's Documents folder.

Variable	Default	Purpose
CIVIL3D_FILE_ROOTS	User Documents	Shared fallback roots for imports and exports.
CIVIL3D_IMPORT_ROOTS	CIVIL3D_FILE_ROOTS	Optional import-only roots for templates, DEM files, LandXML, STM, and other source artifacts.
CIVIL3D_EXPORT_ROOTS	CIVIL3D_FILE_ROOTS	Optional export-only roots for drawings and generated reports.

Import/export tools enforce operation-specific extensions. Generated text and
CSV artifacts are written to a temporary file in the destination directory and
then atomically moved into place. Existing files are rejected unless the tool
call explicitly supplies overwrite: true.

Plugin logging

The native plugin writes a rotating log to
%LOCALAPPDATA%\Civil3DMcpPlugin\plugin.log (5 MiB per file, three backups).
Set CIVIL3D_MCP_LOG_DIR or CIVIL3D_MCP_LOG_LEVEL before launching Civil 3D
to override its directory or minimum level. Plugin health reports
logFilePath, fileLoggingHealthy, and fileLoggingError, so a file-write
failure cannot remain silent.

HTTP bridge endpoints

Method	Path	Notes
GET	/health	Cheap liveness (bridge status + registered tool count). Does not touch the Civil 3D plugin.
GET	/health/live	Explicit alias for cheap bridge liveness.
GET	/health?deep=1	Runs the civil3d_health tool, which round-trips to the plugin. Use when you need to know Civil 3D is actually reachable.
GET	/health/ready	Readiness across the bridge, plugin connection, and bounded host queue; returns 503 when unavailable or full.
GET	/health/plugin	Native plugin health and drawing telemetry.
GET	/health/queue	Host queue and background-job health.
GET	/health/version	Package, MCP SDK, and Node dependency versions without probing Civil 3D.
GET	/tools	Full internal route catalog (219 names), independent of compact MCP exposure.
POST	/execute	{ "tool": "<name>", "parameters": { ... } } — invokes any registered tool or legacy alias.

Example: enable the shared-secret token

$env:MCP_HTTP_TOKEN = "change-me-to-a-long-random-string"
npm run start

Then from the Copilot or any client:

POST /execute HTTP/1.1
Host: 127.0.0.1:3000
Authorization: Bearer change-me-to-a-long-random-string
Content-Type: application/json

{ "tool": "civil3d_health", "parameters": {} }

Verify the live Civil 3D plugin

With Civil 3D open, a drawing active, and C3DMCPSTATUS reporting port 8080,
run this read-only P0 smoke check:

npm run test:live-plugin

The full opt-in host suite creates disposable drawings and covers query,
concurrency, document switching, create/undo, temporary volume-surface
rollback, delete, job completion, and cancellation. It is guarded to prevent
accidental mutations:

$env:CIVIL3D_LIVE_SMOKE_CONFIRM = "DISPOSABLE_DRAWING"
$env:CIVIL3D_LIVE_SMOKE_QC_PATH = "$env:USERPROFILE\Documents\civil3d-mcp-live-qc.txt"
npm run test:live-host

To validate the richer contracts through a spawned production stdio MCP client
(typed tools, annotations, progress, resources, health, and drawing context), run:

npm run test:live-mcp-client

For safe-to-retry actions, clients may provide an idempotencyKey (maximum 128
characters). Identical calls share the in-flight or recent result for two
minutes; reusing the key with different parameters returns CIVIL3D.CONFLICT.

It calls getCivil3DHealth and retrieves drawing context without mutating the
open drawing. Set CIVIL3D_HOST and CIVIL3D_PORT first if the plugin does not
use the default loopback endpoint.

---

Troubleshooting

"Cannot connect to Civil 3D plugin"

• Civil 3D must be open with a drawing loaded
• Type C3DMCPSTATUS in Civil 3D — confirm the server shows as running on port 8080
• Check Windows Firewall is not blocking localhost:8080
• If you moved the plugin to a non-default port, set CIVIL3D_PORT on the Node side to match

"No active document"

• Open a .dwg file in Civil 3D before making any tool calls

"Alignment/Surface not found"

• Names are case-insensitive but must otherwise match exactly
• Use the corresponding list tool first (e.g. civil3d_alignment → list action)

"I cannot see a specialized alias in my MCP client"

• This is expected with the recommended compact 34-tool surface
• Call the canonical domain tool with its action, or set CIVIL3D_ENABLE_TOOL_ALIASES=true in the MCP server configuration
• Restart the MCP client connection after changing the environment; changing an unrelated terminal does not update an already-running client-managed server
• Use civil3d://catalog/tools or tools.generated.md to map aliases to canonical actions

Plugin won't load

• Verify the DLL targets the correct Civil 3D version
• Ensure Civil 3D and Visual Studio are running as the same Windows user (no elevation mismatch)
• Check the DLL path passed to NETLOAD has no spaces or special characters

---

Documentation

Doc	Description
DEPLOYMENT.md	Full deployment: Docker, npm, env vars, registry autoload
tools.generated.md	Release-checked canonical and alias catalog generated from the runtime manifest
tools.md	Extended parameter and workflow reference
CHANGELOG.md	Release history
ROADMAP.md	Production-readiness phases and live-validation evidence

---

Contributing

Pull requests are welcome. For major changes, open an issue first to discuss what you'd like to change.

1. Fork the repository
2. Create your feature branch (git checkout -b feature/my-tool)
3. Commit your changes (git commit -m 'Add civil3d_my_tool')
4. Push to the branch (git push origin feature/my-tool)
5. Open a Pull Request

---

License

MIT — Steven Bouldin