{"slug": "mcp-server-not-showing-in-claude-code-or-codex-find-out-which-of-three-problems", "title": "MCP server not showing in Claude Code or Codex? Find out which of three problems you have", "summary": "A troubleshooting guide lays out three distinct failure modes for MCP servers that appear broken in Claude Code or Codex — a server missing from the list, a server that fails to start, or a server that needs authentication — and gives the specific commands and config locations for each. It notes that Claude Code stores servers in ~/.claude.json or a project's .mcp.json while Codex uses ~/.codex/config.toml, and that the two tools never read each other's files. Common startup failures trace to PATH differences for node, npx, uvx or docker, and can be addressed with the MCP_TIMEOUT variable in Claude Code or startup_timeout_sec in Codex.", "body_md": "\"The MCP server is not working\" can mean three different things, and each has a different fix. Before you edit any configuration, find out which one you have:\n\n|  | Claude Code | Codex | \n|---|---|---|\n| List servers | `claude mcp list` , or`/mcp` in a session | `codex mcp list` , or`/mcp` in the TUI | \n| Add a local server | `claude mcp add <name> -- <command> [args]` | `codex mcp add <name> -- <command>` | \n| Add a remote server | `claude mcp add --transport http <name> <url>` | `codex mcp add <name> --url <url>` | \n| Stored in | `~/.claude.json` (local and user scope) or`.mcp.json` in the project root (project scope) | `~/.codex/config.toml` , or`.codex/config.toml` in a trusted project, under`[mcp_servers.<name>]` | \n\nThe desktop app, CLI and IDE extension of Codex share one configuration. Claude Code and Codex never read each other's files, so a server added to one is invisible to the other.\n\n`--scope user` makes it available in every project.`.mcp.json` waits for your approval the first time Claude Code opens that folder. Until then it shows `Pending approval`.\nClaude Code shows `Connected`, `Needs authentication` or `Failed to connect`.\n\n`/mcp` and sign in, or `claude mcp login <name>` from the terminal. In Codex, run `codex mcp login <name>`.` node`, `npx`, `uvx` or `docker` is the most common cause. An application started from a desktop shortcut may not see the same `PATH` as your terminal.`MCP_TIMEOUT` environment variable in milliseconds (`MCP_TIMEOUT=10000 claude`). Codex uses `startup_timeout_sec` in the server's entry; the default is 10 seconds.\nA local server that fails to start is not retried automatically in Claude Code. After you fix it, choose **Reconnect** in `/mcp`. Change one thing at a time and look at the status again after each change.\n\nThe application and version, the scope or config file, the server name, how it connects (local command or URL), the status shown and the exact error message. Remove tokens and private data first.\n\nThe same checklist, with more detail on each state: [MCP server not showing in Claude Code or Codex](https://www.agentflowshub.com/en/learn/mcp-server-not-showing)\n\n*Written with AI assistance.*", "url": "https://wpnews.pro/news/mcp-server-not-showing-in-claude-code-or-codex-find-out-which-of-three-problems", "canonical_source": "https://dev.to/agentflowshub/mcp-server-not-showing-in-claude-code-or-codex-find-out-which-of-three-problems-you-have-4c33", "published_at": "2026-11-04 11:24:35+00:00", "updated_at": "2026-11-04 11:27:47.866688+00:00", "lang": "en", "topics": ["ai-agents", "agent-protocols", "developer-tools", "ai-tools"], "entities": ["Claude Code", "Codex", "Anthropic", "OpenAI", "MCP"], "also_reported_by": [], "alternates": {"html": "https://wpnews.pro/news/mcp-server-not-showing-in-claude-code-or-codex-find-out-which-of-three-problems", "markdown": "https://wpnews.pro/news/mcp-server-not-showing-in-claude-code-or-codex-find-out-which-of-three-problems.md", "text": "https://wpnews.pro/news/mcp-server-not-showing-in-claude-code-or-codex-find-out-which-of-three-problems.txt", "jsonld": "https://wpnews.pro/news/mcp-server-not-showing-in-claude-code-or-codex-find-out-which-of-three-problems.jsonld"}}