RimWorld Modder MCP

MCP server for RimWorld mod analysis and modding workflows, implemented in C#/.NET 10.

Primary focus:

• XML defs and inheritance
• patch inspection and conflict triage
• mod compatibility and dependency checks
• Player.log triage
• release-readiness checks for RimWorld mods

Quickstart

Recommended: global .NET tool

Requires a .NET 10 SDK.

dotnet tool install -g cryptiklemur.rimworld-modder-mcp

Most MCP clients can then use:

{
  "mcpServers": {
    "rimworld-modder": {
      "command": "rimworld-modder-mcp",
      "args": [
        "--rimworld-path=/absolute/path/to/RimWorld",
        "--mod-dirs=/absolute/path/to/RimWorld/Mods"
      ]
    }
  }
}

Repo examples:

• claude-desktop-config.json
• local-mcp-config.json

Recommended: repo-local config

Create .rimworld-modder-mcp.json in your mod repo:

{
  "rimworldPath": "/absolute/path/to/RimWorld",
  "modDirs": [
    "/absolute/path/to/RimWorld/Mods",
    "/absolute/path/to/Steam/workshop/content/294100"
  ],
  "logPath": "/absolute/path/to/Player.log",
  "allowedDlcs": "Core,Biotech",
  "outputMode": "compact"
}

Then your MCP client args can just be:

{
  "mcpServers": {
    "rimworld-modder": {
      "command": "rimworld-modder-mcp",
      "args": [
        "--project-root=/absolute/path/to/your/mod/repo"
      ]
    }
  }
}

No-install option

If you do not want a global install, use dnx or dotnet tool exec. This also requires a .NET 10 SDK.

Direct shell usage:

dnx cryptiklemur.rimworld-modder-mcp --yes -- --project-root=/absolute/path/to/your/mod/repo

dotnet tool exec cryptiklemur.rimworld-modder-mcp --yes -- --project-root=/absolute/path/to/your/mod/repo

Headless MCP config with dnx:

{
  "mcpServers": {
    "rimworld-modder": {
      "command": "dnx",
      "args": [
        "cryptiklemur.rimworld-modder-mcp",
        "--yes",
        "--",
        "--project-root=/absolute/path/to/your/mod/repo"
      ]
    }
  }
}

--yes is there so first-run package download does not pause for confirmation.

Client Setup

Pick the client you care about:

codex mcp add rimworld-modder -- \
  rimworld-modder-mcp \
  --project-root=/absolute/path/to/your/mod/repo

codex mcp add rimworld-modder -- \
  dnx cryptiklemur.rimworld-modder-mcp \
  --yes \
  -- \
  --project-root=/absolute/path/to/your/mod/repo

claude mcp add --scope user rimworld-modder -- \
  rimworld-modder-mcp \
  --project-root=/absolute/path/to/your/mod/repo

claude mcp add --scope user rimworld-modder -- \
  dnx cryptiklemur.rimworld-modder-mcp \
  --yes \
  -- \
  --project-root=/absolute/path/to/your/mod/repo

goose session \
  --with-extension "rimworld-modder-mcp --project-root=/absolute/path/to/your/mod/repo"

goose session \
  --with-extension "dnx cryptiklemur.rimworld-modder-mcp --yes -- --project-root=/absolute/path/to/your/mod/repo"

Runtime-Only Fallback

If you only want the runtime, use the release bundle instead of the NuGet tool.

1. Install the .NET 10 runtime.
2. Download the latest rimworld-modder-mcp-vX.Y.Z-dotnet.zip from GitHub Releases.
3. Extract it somewhere permanent.
4. Point your MCP client at RimWorldModderMcp.dll.

Bundle config:

{
  "mcpServers": {
    "rimworld-modder": {
      "command": "dotnet",
      "args": [
        "/absolute/path/to/RimWorldModderMcp.dll",
        "--rimworld-path=/absolute/path/to/RimWorld",
        "--mod-dirs=/absolute/path/to/RimWorld/Mods"
      ]
    }
  }
}

Each bundle also includes:

• manifest.json
• QUICKSTART.md
• examples/generic-mcp-config.posix.json
• examples/generic-mcp-config.windows.json

Docker

Build:

docker build -t rimworld-modder-mcp .

Run:

docker run \
  -i \
  --rm \
  -v "/path/to/rimworld:/rimworld:ro" \
  -v "/path/to/workshop:/workshop:ro" \
  rimworld-modder-mcp \
  --rimworld-path=/rimworld \
  --mod-dirs=/rimworld/Mods,/workshop

MCP config:

{
  "mcpServers": {
    "rimworld-modder": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-v", "/path/to/rimworld:/rimworld:ro",
        "-v", "/path/to/workshop:/workshop:ro",
        "ghcr.io/cryptiklemur/rimworld-modder-mcp:latest",
        "--rimworld-path=/rimworld",
        "--mod-dirs=/rimworld/Mods,/workshop"
      ]
    }
  }
}

Arguments

Common optional:

• --project-root repo root used for config discovery and relative path resolution
• --config explicit project config path
• --rimworld-path path to the RimWorld install if you are not using project config
• --mod-dirs comma-separated mod directories
• --mods-config-path path to ModsConfig.xml if you only want enabled mods
• --logPath path to Player.log
• --allowedDlcs official-content target for compatibility checks, default Core,Biotech
• --log-level Debug, Information, Warning, or Error
• --scopeType and --scopeValue for audit_scope

Common RimWorld paths:

• Windows Steam: D:\SteamLibrary\steamapps\common\RimWorld
• Linux Steam: ~/.steam/steam/steamapps/common/RimWorld
• macOS Steam: ~/Library/Application Support/Steam/steamapps/common/RimWorld

Run rimworld-modder-mcp --help for the full argument list.

Output Controls

• outputMode: compact, normal, or detailed
• pageSize: cap array-heavy sections
• pageOffset: page through array-heavy sections
• handleResults: store a retrievable result handle
• get_result_by_handle: expand a stored handle in a long-lived MCP session

Core Workflow Tools

Start here in most mod repos:

• Setup and environment: doctor
• Changed-file review before commit: audit_changed_files, validate_changed_content
• Runtime debugging: triage_player_log, compare_player_logs, broken_reference_explainer
• Release/readiness checks: mod_ready_check, scan_dlc_dependencies
• Patch debugging: triage_patch_conflicts, find_patch_hotspots, validate_xpath, write_xpath, preview_patch, preview_patch_result
• Scoped inspection: scope_search, audit_scope, content_coverage_report
• Load-order impact: suggest_load_order, load_order_impact_report

Lower-level lookup tools are still available when you need exact details:

• Def lookup: get_def, search_defs, get_defs_by_type, get_def_inheritance_tree, compare_defs
• References and patches: get_references, get_def_dependencies, get_patches_for_def, get_patch_conflicts
• Mod analysis: analyze_mod_compatibility, get_mod_dependencies, find_broken_references, validate_mod_structure

Your MCP client can inspect the full tool list directly.

Build From Source

git clone https://github.com/cryptiklemur/rimworld-modder-mcp.git
cd rimworld-modder-mcp
dotnet build src/RimWorldModderMcp/RimWorldModderMcp.csproj
dotnet run --project src/RimWorldModderMcp/RimWorldModderMcp.csproj -- --rimworld-path="/path/to/RimWorld"

Release

semantic-release publishes:

• the NuGet .NET tool
• the .nupkg as a GitHub release asset
• the runtime-only zip bundle
• the .sha256 checksum

Trusted Publishing on nuget.org:

1. In nuget.org, open Trusted Publishing.
2. Add a GitHub Actions policy for:
   • repository owner: cryptiklemur
   • repository: rimworld-modder-mcp
   • workflow file: release.yml
3. In GitHub repo settings, add a repository variable:
   • NUGET_USERNAME = your nuget.org profile name

After that, no long-lived NuGet API key secret is needed.

Useful commands:

npm ci
npm run release:dry-run
npm run release:prepare-artifacts -- 1.2.5

CI configuration:

• NuGet Trusted Publishing via NuGet/login@v1
• repo variable NUGET_USERNAME
• SEMANTIC_RELEASE_TOKEN if you want release-created tags to trigger other workflows