Cities2 MCP and Modding Toolkit

io.github.mayor-modderPublished by GitHub account mayor-modderv0.5.0Updated Nov 1, 2026

Cities: Skylines II wiki, encyclopedia, and mod workflow tools for AI agents.

VerifiedSTDIODesktop onlyKnowledge & MemoryDeveloper Tools

Overview

AI-generated overview

Local MCP server giving assistants a searchable Cities: Skylines II wiki and research corpus, the in-game encyclopedia, and CS2 mod project workflow tools.

What you can do
  • Search, read and cite the bundled Cities: Skylines II wiki corpus and curated research datasets, including full pages, page-level references and modding code snippets
  • Search and read entries from the locally installed in-game encyclopedia
  • Scaffold C# or UI mod projects from templates, list project trees and write files inside a configured workspace
  • Run static analysis, build projects with normalized diagnostics, and package mod output as a zip
  • Report which sources (wiki corpus, research datasets, local encyclopedia) are available
When to use it
Useful when you want an assistant to answer Cities: Skylines II gameplay, patch-note or modding questions with source notes, or to scaffold, inspect, build and package CS2 mod projects on your own machine.
Requirements
Runs locally over stdio as a PyPI package (cities2-mcp), so a Python environment is needed. The in-game encyclopedia source requires a local Cities: Skylines II install; optional environment variables CITIES2_GAME_DIR, CITIES2_LOCALE_COK and CITIES2_MODS_DIR point at the game directory, Locale.cok and the Mods directory. No authentication is declared.
Before you install
The workflow tools write files inside configured workspaces and build_project executes trusted workspace code, so only point them at repositories you trust. Builds and packaging change local project files. The encyclopedia index is cached locally from installed game files. The project is in active development and client behavior can vary by host and version; mods should be playtested before sharing.

Installation

In SourceWeft

  1. Open Cities2 MCP and Modding Toolkit in the dashboard and add it to a workspace.
  2. Enable the server for the chats that should use its tools.

Desktop only via STDIO. STDIO servers start a local process, so they need the SourceWeft desktop host.

Other MCP clients

Follow the launch instructions in the repository.

README

Cities2 MCP and Modding Toolkit

Cities2 MCP and Modding Toolkit is a local MCP server and agent skill bundle for Cities: Skylines II gameplay questions, patch notes, and mod project workflows.

It gives AI agents access to a bundled, searchable Cities: Skylines II Wiki corpus, separately attributed curated research reports, and, when the game is installed locally, the in-game encyclopedia. Agents can use those sources to answer gameplay questions, summarize patch/update information, and explain city systems with source notes. The package also includes five agent skills for game knowledge, modding, review, debugging, and release readiness, plus local MCP workflow tools for scaffolding, inspecting, building, and packaging CS2 mod projects inside trusted workspaces.

The plugin is in active development. Package checks, direct MCP smoke tests, and selected client workflows are covered in the repository test suite and eval reports, but client plugin behavior can vary by host and version. See the known issues and eval reports for the latest verification notes.

Quick install

Choose your client: Claude Code | Claude desktop | Codex CLI | Codex app | Google Antigravity

See INSTALL.md for full installation details, direct MCP config, workspace setup, build prerequisites, and troubleshooting.

What it can do

Search game and modding information

The MCP server includes a prepared text corpus from the Cities: Skylines II Wiki. An AI assistant can:

  • search the wiki
  • retrieve full pages, page-level references, and code-oriented snippets for game systems, patch notes, and modding topics
  • answer questions about game mechanics, recent updates, and how city systems affect your save

Search curated research

The MCP server also bundles curated Cities: Skylines II research reports. These reports are historically situated, separately attributed, and generated from committed research notes rather than raw transcripts. Results retain publication and source context so an assistant can distinguish time-bounded findings from current game behavior and APIs.

Search the local game encyclopedia

When Cities: Skylines II is installed locally, the MCP server reads the game encyclopedia from the installed game files. This source is enabled by default when the server can find Cities2_Data/Content/Game/Locale.cok.

The extracted encyclopedia index is cached locally on the user's machine and rebuilt only when the source game file, detected Steam build id, locale, or extractor version changes. Extracted game text is not committed to this repository, shipped in releases, or part of the redistributed wiki corpus.

Help with mod project workflows

The server also includes local workflow tools for CS2 mod projects. An AI assistant can:

  • scaffold C# code, UI, or hybrid mod project templates
  • write files inside configured workspaces
  • list project trees
  • run project builds and analyzers
  • package project output

These tools are meant for local development workflows. Claude, Codex, and Antigravity can use them to write and run trusted workspace code during builds, so configure workspaces deliberately and use manual playtesting before treating any mod as ready to share.

Agent skills

  • cities2-knowledge: answers gameplay, city-system, and player-facing patch/update questions.
  • cities2-modding: handles general modding questions and local mod project workflows.
  • cities2-mod-review: reviews CS2 mods for safety, maintainability, user value, packaging hygiene, and verification gaps.
  • cities2-mod-debugging: helps debug CS2 mod build, packaging, runtime, log, UI debugger, and in-game behavior issues.
  • cities2-mod-release: checks whether a mod is ready to share.

The modding quality skills use documented CS2 best practices and negative constraints as defaults, and they do not present a mod as ready to share until it has been locally playtested.

Privacy

The MCP server runs locally and does not collect telemetry. See PRIVACY.md for details.

Licensing

The MCP server code is licensed under the MIT License. The included wiki corpus is licensed under Creative Commons Attribution-ShareAlike 3.0; its source attribution and transformation notes are in the wiki corpus attribution. The curated research corpus is separately attributed, and its original report prose follows the repository license; see the research corpus attribution.

This project is not developed by, endorsed by, reviewed by, or approved by Paradox Interactive, Iceflake Studios, Colossal Order, Paradox Wikis, or any related company. Cities: Skylines II and related names are used referentially.

Source: README.md at commit 232ac5f

Tools

13

get_page

Get Wiki Page

Return a full page from the bundled Cities: Skylines II Wiki corpus or research datasets by page_id. Results include dataset labels. Research evidence is time-bounded; check publication dates for current details.

Parameterspage_idrequired

query_reference

Query Wiki References

Search page-level Cities: Skylines II Wiki corpus and research dataset references: titles, sections, URLs, and links. Results include dataset labels. Research evidence is time-bounded; check publication dates for current details.

Parameterslimitqueryrequired

get_snippets

Get Modding Snippets

Retrieve Cities: Skylines II modding code snippets extracted from the bundled wiki corpus.

Parameterslimitqueryrequired

scaffold_project

Scaffold Mod Project

Scaffold a Cities: Skylines II mod project from a template.

Parametersnamerequiredoptionsmetadatatemplaterequiredtarget_dir

write_project_file

Write Project File

Write files inside a configured Cities: Skylines II mod project workspace.

Parametersmodecontentrequiredproject_dirrequiredrelative_pathrequired

list_project_tree

List Project Tree

List files in a configured Cities: Skylines II mod project workspace.

Parametersglobmax_filesproject_dirrequiredinclude_hidden

build_project

Build Mod Project

Build a Cities: Skylines II mod project and return normalized diagnostics. This executes trusted workspace code; do not use it for arbitrary untrusted repositories.

Parameterscleanstepspackageprofileproject_dirrequiredtimeout_sec

analyze_project

Analyze Mod Project

Run static checks for Cities: Skylines II mod project structure and lifecycle patterns.

Parametersstrictprofileproject_dirrequired

package_project

Package Mod Project

Create a zip package for a Cities: Skylines II mod project.

Parametersoutput_dirproject_dirrequiredpackage_nameexclude_globs

search_encyclopedia

Search game encyclopedia

Search the local Cities: Skylines II in-game encyclopedia read from the user's installed game files.

Parameterslimitqueryrequired

get_encyclopedia_entry

Get encyclopedia entry

Return one local Cities: Skylines II in-game encyclopedia entry by entry_id.

Parametersentry_idrequired

source_status

Check Source Status

Report Cities2-MCP source availability for the wiki corpus, bundled research datasets, and local game encyclopedia.

Takes no parameters.

Version history

3
  1. v0.5.0LatestNov 1, 2026
  2. v0.4.0Sep 19, 2026
  3. v0.3.1Sep 16, 2026

Score

90% of the applicable checks met

How complete this listing is, computed from the registry entry, the endpoint and public sources. Not a rating of the server and not a statement that it is safe or working today: reachability is a dated check, and no installs or reviews go into the score.

  • Reached in the last 30 days25 pts
  • Auth declared10 pts

    Declare the credential headers in the registry entry, or keep the endpoint answering the probe so its auth can be classified.

  • Tools listedRequired15 pts
  • DescriptionRequired15 pts
  • Logo10 pts
  • Documentation15 pts
  • License10 pts