Add Xcode installation guide for Codex and Claude Agent

Author: RossTarrant

docs/installation-guides/README.md

@@ -13,6 +13,7 @@ This directory contains detailed installation instructions for the GitHub MCP Se
 - **[OpenAI Codex](install-codex.md)** - Installation guide for OpenAI Codex
 - **[Roo Code](install-roo-code.md)** - Installation guide for Roo Code
 - **[Windsurf](install-windsurf.md)** - Installation guide for Windsurf IDE
+- **[Xcode (Codex & Claude Agent)](install-xcode.md)** - Installation guide for Codex and Claude Agent within Xcode
 
 ## Support by Host Application
 
@@ -32,6 +33,8 @@ This directory contains detailed installation instructions for the GitHub MCP Se
 | Windsurf | ✅ | ✅ PAT + ❌ No OAuth | Docker or Go build, GitHub PAT | Easy |
 | Copilot in Xcode | ✅ | ✅ Full (OAuth + PAT) | Local: Docker or Go build, GitHub PAT<br>Remote: Copilot for Xcode 0.41.0+ | Easy |
 | Copilot in Eclipse | ✅ | ✅ Full (OAuth + PAT) | Local: Docker or Go build, GitHub PAT<br>Remote: Eclipse Plug-in for Copilot 0.10.0+ | Easy |
+| Xcode (Codex) | ✅ | ✅ PAT + ❌ No OAuth | Local: Docker (full path required), GitHub PAT<br>Remote: GitHub PAT + env var | Easy |
+| Xcode (Claude Agent) | ✅ | ✅ PAT + ❌ No OAuth | Local: Docker (full path required), GitHub PAT<br>Remote: GitHub PAT | Easy |
 
 **Legend:**
 - ✅ = Fully supported

docs/installation-guides/install-xcode.md

@@ -0,0 +1,43 @@
+# Install GitHub MCP Server in Xcode
+
+Xcode currently supports two built-in coding agents: **Codex** (powered by OpenAI) and **Claude Agent** (powered by Anthropic). Follow the standard installation guide for each agent, with one important difference: Xcode uses its own isolated configuration directories for each agent, separate from your global config.
+
+> Configurations placed in these directories only affect agents when launched from Xcode. See [Apple's documentation](https://developer.apple.com/documentation/xcode/setting-up-coding-intelligence#Customize-the-Claude-Agent-and-Codex-environments) for more details.
+
+## Configuration Directories
+
+| Agent | Configuration Directory |
+|-------|------------------------|
+| Codex | `~/Library/Developer/Xcode/CodingAssistant/codex/` |
+| Claude Agent | `~/Library/Developer/Xcode/CodingAssistant/ClaudeAgentConfig/` |
+
+Place your MCP server configuration in the relevant directory above rather than the default location used by the standalone CLI.
+
+## Setup Guides
+
+- **[Codex](install-codex.md)** — configure `config.toml` inside `~/Library/Developer/Xcode/CodingAssistant/codex/`
+- **[Claude Agent](install-claude.md#claude-desktop)** — configure `.claude.json` inside `~/Library/Developer/Xcode/CodingAssistant/ClaudeAgentConfig/`
+
+## macOS Path Note
+
+Xcode runs with a minimal `PATH` that typically excludes `/usr/local/bin`. If you are using a local STDIO server (e.g. Docker or a pre-built binary), use the **full path** to the command in your config:
+
+```
+/usr/local/bin/docker
+/usr/local/bin/github-mcp-server
+```
+
+## Troubleshooting
+
+| Issue | Possible Cause | Fix |
+|-------|----------------|-----|
+| Tools not loading | Config placed in wrong directory | Ensure config is in the Xcode-specific path above, not `~/.codex/` or `~/.claude.json` |
+| Command not found (STDIO) | Xcode's PATH excludes `/usr/local/bin` | Use the full path to the command |
+| Docker not found | Docker not running | Start Docker Desktop and restart Xcode |
+| Authentication failed | Invalid or expired PAT | Regenerate PAT and update config |
+
+## References
+
+- [Apple Developer Documentation — Setting up coding intelligence](https://developer.apple.com/documentation/xcode/setting-up-coding-intelligence#Customize-the-Claude-Agent-and-Codex-environments)
+- [Codex MCP documentation](https://developers.openai.com/codex/mcp)
+- Main project README: [Advanced configuration options](../../README.md)