rhino-mcp: Instructions file for Claude Code

CLAUDE.md

rhino-mcp CLAUDE.md is an instructions file for Claude Code from EaseHee/rhino-mcp. It costs 1,060 tokens per session, scanned A, original, MIT.

Project instructions for rhino-mcp, a server that lets AI assistants read and control McNeel Rhino 8 and Grasshopper, software for 3D modeling and visual programming. They describe its Python code, C# bridge, tools, tests, documentation, and build checks.

In plain words
What is it for?
Use them when developing, testing, linting, type-checking, or extending the Rhino and Grasshopper connection.
Why use it?
They give an AI coding agent the project's layout, development commands, and conventions so changes fit the existing system.

Instructions file for Claude Code

Written for Claude Code: the file is CLAUDE.md. Also seen: reads .claude/ paths; mentions subagents.

This is EaseHee/rhino-mcp's own configuration. It tells Claude Code how to work on rhino-mcp itself, so it is not a mod to install elsewhere. Copy it as a starting point and replace the rules that are about this project. Everything rhino-mcp configures →

Reuse

Borrowing it

Nothing to install: this file belongs to EaseHee/rhino-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.

Copy the file
curl -O https://raw.githubusercontent.com/EaseHee/rhino-mcp/main/CLAUDE.md
Clone the repo
git clone --depth 1 https://github.com/EaseHee/rhino-mcp

Made for: Claude Code.

Wrote this? Show the measurements

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README.md
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Per session 1,060 This file is loaded in full into every session.
When invoked 1,060 The same file — it is already loaded in full.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5.1 $0.01060 $0.01060
Opus 5 $0.00530 $0.00530
Sonnet 5 $0.00212 $0.00212
Haiku 4.5 $0.00106 $0.00106

Measured 7d ago against content hash df09a26d6e6d, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

rhino-mcp CLAUDE.md 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 7d 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.

CLAUDE.md · 79 lines

How it starts

The opening of the file, as written. The whole thing — 79 lines — stays where its author put it; the contents beside it link to each section on GitHub.

rhino-mcp

MCP server connecting Claude to McNeel Rhino 8 and Grasshopper.

Architecture

  • Standalone: rhino3dm (headless Python lib) for .3dm I/O. ~234 tools.
  • Bridge: C# plugin rhino_plugin/csharp/rhino-mcp.rhp over JSON-RPC 2.0. ~235 tools.
  • Mode auto-detected at startup (detect_mode()); override via RHINO_MCP_FORCE_MODE.

Project layout (top level)

  • src/rhino_mcp/ — Python package (server, tools, bridge transports, prompts, models, utils, data).
  • rhino_plugin/csharp/ — C# bridge plugin (Plugin.cs, BridgeServer.cs, CommandDispatcher.cs, Handlers/*.cs, manifest.yml).
  • tests/ — pytest (~262 tests).
  • examples/ — runnable demo scripts (architectural massing, schedule, sun study, etc.).
  • docs/{en,ko}/ — capabilities / configuration / installation / troubleshooting / tools-reference / grasshopper-guide.
  • .github/workflows/ — CI + release pipelines.
  • .claude/ — agents, skills, commands, rules, settings.

Development

uv sync
uv pip install -e '.[dev]'
uv run pytest tests/ -v                    # all tests
uv run ruff check src/ tests/              # lint
uv run mypy src/rhino_mcp                  # type check
dotnet build rhino_plugin/csharp -c Release

Conventions

  • Tool first argument: args: _InputModel (Pydantic BaseModel).
  • doc_id defaults to "active".
  • Shared logic lives in tools/_helpers.py.
  • Mode enum: STANDALONE / BRIDGE / BOTH.
  • Commit messages: English title + English body, Conventional Commits, no Co-Authored-By.
  • Code comments: English only.
  • Korean prose (chat replies, *.ko.md, docs/ko/**, CHANGELOG entries) uses noun-form endings, no honorifics (-함, -임, or noun direct termination; never 입니다 / 합니다 / 하세요).

Procedure docs (lazy-loaded under .claude/rules/)

  • Adding a new tool — .claude/rules/adding-tool.md.
  • C# handler authoring + RhinoCommon trap list — .claude/rules/csharp-handler.md.
  • Korean writing style — .claude/rules/korean-style.md.

Read the full file on GitHub · 79 lines

Changes

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.

  1. 7d ago First seen · 79 lines · 1,060 tokens per session scan A df09a26d6e6d

Subscribe to this mod's changes

rhino-mcp CLAUDE.md is an instructions file published in the GitHub repository EaseHee/rhino-mcp (5 stars, last pushed 3mo ago), licensed MIT. It adds 1,060 tokens to every session, about $0.0053 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 2026-08-31.

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