Claude Desktop needs OAuth or an mcp-remote bridge to use API-key MCP servers

With the bridge in place, Claude Desktop only talks to a local process. The Desktop config entry is a stdio server with the command `npx`. Its arguments are `mcp-remote`, the remote URL and a header ^[12]. mcp-remote runs locally and sends static headers to the remote endpoint ^[11]. That account comes from a survey of six MCP clients by a developer who works on PinkWallet's agent payments product ^[1]. The author re-fetched every quoted doc on 2026-09-30 ^[4].

The header argument is written `"Authorization:${AUTH_HEADER}"`. There is no space after the colon, and the bearer value sits in the `env` block ^[12]. That layout works around a bug the post describes: when Cursor, Codex-Cli and Claude Desktop on Windows invoke npx, spaces inside args are not escaped, and the values get mangled ^[13]. If you write the header the obvious way, with a space, it silently breaks on those platforms, the author wrote ^[14].

The limit is in Desktop's connector UI. Anthropic's support docs describe a sign-in: "you'll typically go through an OAuth authentication process to securely sign in" ^[7]. The advanced path is still OAuth: "Optionally, click 'Advanced settings' to specify an OAuth Client ID and OAuth Client Secret for your server." ^[8] Anthropic does not document a field for a static bearer token or API key ^[2]. `claude_desktop_config.json` looks as if it should accept `url` and `headers` the way Cursor's and VS Code's configs do. According to the author, it does not for servers added through the connectors UI ^[9].

In every other client, the key goes in a header. Claude Code takes it in one command: `claude mcp add --transport http secure-api https://api.example.com/mcp --header "Authorization: Bearer your-token"`. The `--header` flag, or `-H`, can be repeated ^[5]. The author calls Claude Code the lowest-friction of the six ^[6]. The post says the OpenAI Agents SDK and LangChain also take a headers object or flag directly ^[3]. That makes five of the six clients that accept the key without a bridge ^[1].

The bigger difference between clients is where the secret is stored. Cursor interpolates `${env:MY_SERVICE_TOKEN}`, so the raw key never has to be written into `mcp.json` ^[15]. The failure the author sees is people skipping the interpolation and committing the literal key. The docs example works either way, so nothing stops them ^[16]. VS Code resolves `${input:api-key}` from a `promptString` input marked `"password": true`, and asks for the value when the server first starts ^[17]. The mcp-remote example writes `"Bearer YOUR_KEY"` as a literal string in the Desktop config's `env` block ^[12].

The author offers two options: put OAuth in front of the server, or bridge it ^[10]. I think the right one depends on who uses the server. For an internal server with a few Desktop users, the bridge costs a config block per machine, an npx-launched process and the Windows quoting rule. For a server offered to customers, I would put OAuth in front. The author calls that more work, but it is the path Desktop supports natively ^[10]. The author also says most static-key servers recommend mcp-remote for Desktop today ^[11].