9c47f73602
Here's the PR summary:
---
## Enforce semver validation for `MCPApp` versioning
### Problem
`MCPApp.__init__` accepted any string as `version` with no validation.
Invalid versions like `"1.0.0dev"` or `"latest"` silently propagated to
the Engine, where `compareToolVersions` fell back to lexicographic
`strings.Compare` instead of `semver.Compare` — causing incorrect
ordering (e.g. `1.10.0 < 1.9.0`).
### Solution
Validate and normalize `version` at `MCPApp` instantiation time using
the same acceptance rules as Go's `golang.org/x/mod/semver v0.31.0` (the
exact version used by the Engine).
### Changes
**`arcade_mcp_server/_validation.py`** (new file)
- Shared regex constants: `SEMVER_PATTERN` (semver.org spec),
`SHORT_VERSION_PATTERN`, `MAJOR_ONLY_PATTERN`
**`arcade_mcp_server/mcp_app.py`**
- Added `_validate_version()` mirroring the existing `_validate_name()`
pattern
- Added `version` property + setter (validates on mutation too)
- `__init__` now stores `self._version` via `_validate_version()`
**`arcade_mcp_server/settings.py`**
- Added `@field_validator("version")` on `ServerSettings` — covers the
`MCP_SERVER_VERSION` env var path
- Fixed default from `"0.1.0dev"` → `"0.1.0"` (the old default was
itself invalid)
**`pyproject.toml`** — bumped `arcade-mcp-server` `1.17.4` → `1.17.5`
### Normalization pipeline
All inputs are normalized to canonical `MAJOR.MINOR.PATCH` before
storage:
| Input | Stored as |
|-------|-----------|
| `v1.0.0` | `1.0.0` |
| `1.0` / `v1.0` | `1.0.0` |
| `1` / `v1` | `1.0.0` |
### Verification
Validated against `golang.org/x/mod/semver v0.31.0` (Engine's exact
pinned version) — 40/40 accept/reject cases match. The Engine's own
`store_test.go` uses `"1.0"` and `"1.1"` as `ToolkitVersion` values,
confirming short forms are intentionally supported.
### Breaking change
Any user currently passing a non-semver version string (e.g.
`"1.0.0dev"`, `"latest"`) will get a `ValueError` on upgrade. This is
intentional — those versions were silently causing incorrect tool
ordering in the Engine.
Closes TOO-518
<!-- CURSOR_SUMMARY -->
---
> [!NOTE]
> **Medium Risk**
> Introduces stricter version validation/normalization that will raise
errors for previously-accepted non-semver inputs (including via env
vars), which may break existing consumers depending on lax version
strings.
>
> **Overview**
> **Enforces semver for server versioning** across both `MCPApp` and
`ServerSettings`, rejecting invalid strings and normalizing accepted
inputs (e.g., stripping leading `v`, expanding `1`/`1.2` to
`1.0.0`/`1.2.0`).
>
> Adds shared `normalize_version` logic in
`arcade_mcp_server/_validation.py`, updates `MCPApp` to validate on init
and via a new `version` property/setter, and adds a Pydantic `version`
validator so `MCP_SERVER_VERSION` is checked. Defaults are updated from
`0.1.0dev` to `0.1.0`, tests are expanded to cover accept/reject cases,
and the package version is bumped to `1.17.5`.
>
> <sup>Written by [Cursor
Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit
2ceabacb25372e67eef9720b901c1ee2b214868f. This will update automatically
on new commits. Configure
[here](https://cursor.com/dashboard?tab=bugbot).</sup>
<!-- /CURSOR_SUMMARY -->
---------
Co-authored-by: Eric Gustin <34000337+EricGustin@users.noreply.github.com>
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|---|---|---|
| .. | ||
| arcade_mcp_server | ||
| Makefile | ||
| pyproject.toml | ||
| README.md | ||
Arcade MCP Server
Arcade MCP (Model Context Protocol) Server enables AI assistants and development tools to interact with your Arcade tools through a standardized protocol. Build, deploy, and integrate MCP servers seamlessly across different AI platforms.
Quick Links
- Quickstart Guide - Get up and running in minutes
- Walkthrough - Learn by example
- API Reference - MCPApp API documentation
Features
- 🚀 FastAPI-like Interface - Simple, intuitive API with
MCPApp - 🔧 Tool Discovery - Automatic discovery of tools in your project
- 🔌 Multiple Transports - Support for stdio and HTTP/SSE
- 🤖 Multi-Client Support - Works with Claude, Cursor, and more
- 📦 Package Integration - Load installed Arcade packages
- 🔐 Built-in Security - Environment-based configuration and secrets
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- 📊 Production Ready - Deploy with Docker, systemd, PM2, or cloud platforms
Getting Started
Installation
pip install arcade-mcp-server
Create Your First Server
from arcade_mcp_server import MCPApp
from typing import Annotated
app = MCPApp(name="my-tools", version="1.0.0")
@app.tool
def greet(name: Annotated[str, "Name to greet"]) -> str:
"""Greet someone by name."""
return f"Hello, {name}!"
if __name__ == "__main__":
app.run()
Run Your Server
# For development
python my_tools.py
# For Claude Desktop
python -m arcade_mcp_server stdio
# For HTTP clients
python -m arcade_mcp_server --host 0.0.0.0 --port 8080
Community
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Arcade MCP Server collects anonymous usage data to help us improve the service and debug issues. We track "MCP server start" events to understand server usage patterns and reliability.
What We Track
When the server starts, we collect the following information:
- Server configuration: transport type (
httporstdio), host, port - Server metadata: tool count, server version
- Runtime environment: Python version, OS type and release
- Timing: device timestamp
- Errors: error messages (if startup fails)
Privacy
- For anonymous users: Events are tracked with an anonymous ID and no user profile is created
- For authenticated users: Events are linked to your account to help us provide better support
- No sensitive data (credentials, tool inputs/outputs, or personal information) is ever collected
Opt Out
To disable usage tracking, set the environment variable ARCADE_USAGE_TRACKING to 0.
License
Arcade MCP Server is open source software licensed under the MIT license.