I’m trying to use MCP servers with Xcode 26.3 Coding Intelligence (Codex agent). With a project-scoped config file at /.codex/config.toml, MCP servers are not reliably loaded.
<repo>/.codex/config.toml
Example:
[mcp_servers.Notion]
url = "https://mcp.notion.com/mcp"
enabled = true
[mcp_servers.XcodeBuildMCP]
command = "/bin/zsh"
args = ["-lc", "/opt/homebrew/bin/npx -y xcodebuildmcp@beta mcp"]
enabled = true
tool_timeout_sec = 10000
Expected:
Xcode consistently loads MCP servers defined in /.codex/config.toml across restarts.
Actual: Xcode often only exposes xcode-tools. In some sessions MCP servers appear, but after restarting Xcode they may disappear. The global file at ~/Library/Developer/Xcode/CodingAssistant/codex/config.toml also seems managed/rewritten by Xcode and isn’t reliable for custom MCP servers.
Questions
-
Is /.codex/config.toml the official/supported way to configure MCP servers for Codex in Xcode right now?
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Are there any requirements for Xcode to load it (e.g. workspace must be Trusted, open .xcworkspace vs .xcodeproj, full restart/force quit, etc.)?
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Is there any logging/diagnostics to understand why the MCP server is not starting or not being picked up?