Pin Cyclopts to v4.0.0 + compliance note (#2354)

* Pin cyclopts to v5.0.0a1+

* Document cyclopts/docutils licensing

* Update docs

Author: jlowin

README.md

@@ -143,6 +143,8 @@ uv pip install fastmcp
 
 For full installation instructions, including verification, upgrading from the official MCPSDK, and developer setup, see the [**Installation Guide**](https://gofastmcp.com/getting-started/installation).
 
+**Dependency Licensing:** FastMCP depends on Cyclopts for CLI functionality. Cyclopts v4 includes docutils as a transitive dependency, which has complex licensing that may trigger compliance reviews in some organizations. If this is a concern, you can install Cyclopts v5 alpha (`pip install "cyclopts>=5.0.0a1"`) which removes this dependency, or wait for the stable v5 release. See [this issue](https://github.com/BrianPugh/cyclopts/issues/672) for details.
+
 ## Core Concepts
 
 These are the building blocks for creating MCP servers and clients with FastMCP.

docs/getting-started/installation.mdx

@@ -42,6 +42,20 @@ Python version:                            3.12.2
 Platform:            macOS-15.3.1-arm64-arm-64bit
 FastMCP root path:            ~/Developer/fastmcp
 ```
+
+### Dependency Licensing
+
+<Info>
+FastMCP depends on Cyclopts for CLI functionality. Cyclopts v4 includes docutils as a transitive dependency, which has complex licensing that may trigger compliance reviews in some organizations.
+
+If this is a concern, you can install Cyclopts v5 alpha which removes this dependency:
+
+```bash
+pip install "cyclopts>=5.0.0a1"
+```
+
+Alternatively, wait for the stable v5 release. See [this issue](https://github.com/BrianPugh/cyclopts/issues/672) for details.
+</Info>
 ## Upgrading from the Official MCP SDK
 
 Upgrading from the official MCP SDK's FastMCP 1.0 to FastMCP 2.0 is generally straightforward. The core server API is highly compatible, and in many cases, changing your import statement from `from mcp.server.fastmcp import FastMCP` to `from fastmcp import FastMCP` will be sufficient. 

pyproject.toml

@@ -11,7 +11,7 @@ dependencies = [
     "openapi-pydantic>=0.5.1",
     "platformdirs>=4.0.0",
     "rich>=13.9.4",
-    "cyclopts>=3.0.0",
+    "cyclopts>=4.0.0",
     "authlib>=1.6.5",
     "pydantic[email]>=2.11.7",
     "pyperclip>=1.9.0",