docs: clarify headless OAuth process lifetime

README.md

@@ -418,7 +418,7 @@ npx mcporter config add notion https://mcp.notion.com/mcp --auth oauth
 npx mcporter auth notion
 ```
 
-On headless hosts, use `npx mcporter auth notion --no-browser` to print the authorization URL instead of launching the platform browser. Treat the printed URL as sensitive operational output. If you open it on another machine, make sure the printed `redirectUrl` callback port is reachable through a loopback-only tunnel or a configured `oauthRedirectUrl`.
+On headless hosts, use `npx mcporter auth notion --no-browser` to print the authorization URL instead of launching the platform browser. Treat the printed URL as sensitive operational output. Keep the `mcporter auth` process alive until the browser redirects back to the printed `redirectUrl`; process managers that exit or clean up the command after capturing stdout can kill the loopback callback listener before OAuth completes. Run the command from a persistent terminal session, `tmux`, or a supervised background process such as `nohup`, and if you open the URL on another machine, make sure the callback port is reachable through a loopback-only tunnel or a configured `oauthRedirectUrl`.
 
 Providers that do not support dynamic client registration can use a pre-registered app:
 

docs/adhoc.md

@@ -62,7 +62,7 @@ The CLI still avoids surprise prompts during `mcporter list`; the upgrade happen
 
 - OAuth flows are allowed; successful tokens store under the inferred name just like regular definitions.
 - `mcporter auth` accepts the same `--http-url/--stdio` flags (and even bare URLs), so you can immediately re-run `mcporter auth https://…` after a 401 without touching a config file.
-- Use `mcporter auth <url> --no-browser` for human-in-the-loop headless OAuth. Text mode writes only the authorization URL to stdout; `--json --no-browser` writes `authorizationUrl` plus `redirectUrl` as JSON. Keep that URL out of durable CI logs and support bundles.
+- Use `mcporter auth <url> --no-browser` for human-in-the-loop headless OAuth. Text mode writes only the authorization URL to stdout; `--json --no-browser` writes `authorizationUrl` plus `redirectUrl` as JSON. Keep that URL out of durable CI logs and support bundles. The `mcporter auth` process must keep running until the browser redirects to `redirectUrl`; process managers that capture stdout and then tear down the command can kill the local callback listener before tokens are saved. Use a persistent terminal, `tmux`, or a supervised background process such as `nohup` when completing OAuth outside an interactive shell.
 - When opening the URL on a different machine, remember that loopback redirect URLs point at the browser machine unless an SSH tunnel forwards the callback port back to the mcporter process. Use `oauthRedirectUrl` when you need a predictable callback port.
 - Nothing is written to disk unless you pass `--persist /path/to/config.json`. When set, we merge the generated definition into that file (creating it if necessary) so future runs can rely on the standard config pipeline. Ad-hoc HTTP headers are persisted with the entry, so placeholders such as `--header 'Authorization=$env:MY_TOKEN'` keep working through the normal config header resolver.
 

docs/known-issues.md

@@ -16,6 +16,7 @@ This file tracks limitations that users regularly run into. Most of these requir
   - Ask Supabase to accept the MCP scope or publish their scope list.
 - GitHub’s MCP endpoint (`https://api.githubcopilot.com/mcp/`) returns “does not support dynamic client registration” when mcporter attempts to connect. Copilot’s backend expects pre-registered client credentials. Configure `oauthClientId`/`oauthClientSecretEnv` only if the provider gives you a usable OAuth app; otherwise use their supported client or token/header workaround.
 - Some hosted servers reject dynamic client registration before returning any authorization URL. mcporter now fails those flows immediately instead of waiting for a browser callback that cannot arrive. If the provider supports a pre-registered OAuth app, configure `oauthClientId`, `oauthClientSecretEnv`, and the required `oauthTokenEndpointAuthMethod`; otherwise use the provider's supported client or token/header workaround.
+- `mcporter auth <server> --no-browser` still starts a loopback callback server and must stay alive until the browser redirects back. Process managers that run commands in short-lived process groups can print the authorization URL and then reap the process tree, leaving no listener on the callback port and no saved tokens. Run headless OAuth from a persistent terminal, `tmux`, or `nohup`/a supervisor, and use a configured `oauthRedirectUrl` or loopback tunnel when the browser runs elsewhere.
 
 ## Output schemas missing/buggy on many servers