Getting it into your agent
One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.
npx agentmods add rules/rumi-chan/league-client-mcp/league-clientgit clone --depth 1 https://github.com/rumi-chan/league-client-mcpWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/rules/rumi-chan/league-client-mcp/league-client)<a href="https://agentmods.dev/rules/rumi-chan/league-client-mcp/league-client"><img src="https://agentmods.dev/badge/rules/rumi-chan/league-client-mcp/league-client.svg" alt="Measured on agentmods" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.01692 | $0.01692 |
| Opus 5 | $0.00846 | $0.00846 |
| Sonnet 5 | $0.00338 | $0.00338 |
| Haiku 4.5 | $0.00169 | $0.00169 |
Grade A, and why
league-client scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 5d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 150 lines — stays where its author put it; the contents beside it link to each section on GitHub.
League Client MCP
You are working with a live League of Legends Client via the league-client-mcp MCP server.
The server bridges tool calls to a Pengu Loader plugin inside the LoL Client over WebSocket.
Architecture
Cursor Agent ──MCP stdio──► MCP Server (Node.js)
│ ws://127.0.0.1:8080
▼
Pengu Loader Plugin (inside LoL Client)
│ DOM · CSS · JS · LCU fetch()
▼
League of Legends Client (CEF / Ember.js)
League must be running with Pengu Loader active. 16 MCP tools available.
Standard Workflow
1. get_lol_dom_snapshot → map current page, find selectors
2. inject_lol_css → prototype visual changes
3. query_lol_element → verify selector or computed style
4. inject_lol_plugin → add persistent JS + CSS behaviour
5. reload_lol_plugin → iterate after code changes
6. export_plugin_to_pengu → write plugin to disk
7. reload_lol_client → activate exported plugin permanently
Tool Quick Reference
| Tool | When to use |
|---|---|
get_lol_dom_snapshot |
Start of every session — map the page |
query_lol_element |
Verify one selector without a full snapshot |
inject_lol_css |
CSS-only prototyping (replaces previous CSS) |
execute_lol_javascript |
One-off JS reads or quick checks |
inject_lol_plugin |
Persistent behaviour (JS + CSS, survives navigation) |
remove_lol_plugin / reload_lol_plugin |
Teardown or hot-reload a plugin |
export_plugin_to_pengu |
Make a plugin permanent on disk |
lcu_request |
Read/write LCU REST API (game data, summoner, lobby) |
click_lol_element |
Click a UI element |
type_into_lol_element |
Type into an input |
wait_for_lol_element |
Wait for element after navigation |
get_lol_client_state |
Current URL and active plugin names |
get_lol_performance_metrics |
Heap, DOM nodes, paint timings |
get_lol_screenshot |
Capture LeagueClientUx to temp PNG |
reload_lol_client |
Full client reload |
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 5d ago First seen · 150 lines · 1,692 tokens per session scan A 2b8dade86be0
league-client is a cursor rule published in the GitHub repository rumi-chan/league-client-mcp (20 stars, last pushed 5mo ago), licensed MIT. It adds 1,692 tokens to every session, about $0.0085 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other cursor rules, from other repositories
08-client-server
IF 判断当前环境是否为客户端 → FabricLoader.getInstance().getEnvironmentType() == EnvType.CLIENT → World.isClient（Yarn 字段；yarn 1.14.4 World.mapping）。不要用 MCP/Forge 的 isRemote.
07-datagen
IF 生成物品/方块模型 JSON → 手动编写 JSON 在 src/main/resources/assets/{modid}/models/.
meta-quest-agentic-tools
Use Meta Quest Agentic Tools for Meta Quest and Horizon OS samples.
narrative-writing
游戏叙事写作助手行为约束（game-narrative-mcp）.
meta-quest-agentic-tools
Use Meta Quest Agentic Tools for Meta Quest and Horizon OS samples.
visual-and-observational-rules
Defines the visual aspects of the game and how the player observes the world. This includes map color-coding, screen effects, and the overall simulation style.