Document ad-hoc server workflow

docs/adhoc.md

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+# Ad-hoc MCP Servers
+
+`mcporter` is gaining support for "just try it" workflows where you point the CLI at a raw MCP endpoint without first editing a config file. This doc tracks the behavior and heuristics we use to make that experience smooth while keeping the runtime predictable.
+
+## Entry Points
+
+Two new flag sets let you describe a server on the command line:
+
+- `mcporter list --http-url https://mcp.linear.app/mcp [--name linear]`
+- `mcporter call --stdio "bun run ./server.ts" --name local-tools`
+
+You can also pass a bare URL as the selector (`mcporter list https://mcp.linear.app/mcp`) or embed the URL in a `call` expression (`mcporter call 'https://mcp.example.com/tools.generate({ topic: "release" })'`).
+
+## Transport Detection
+
+- **HTTP(S)**: Providing a URL defaults to the streamable HTTP transport. `https://` works out of the box; `http://` requires `--allow-http` to acknowledge cleartext traffic.
+- **STDIO**: Supplying `--stdio` (with a command string) or `--stdio-bin` (binary + args) selects the stdio transport. We accept optional `--cwd` and `--env KEY=value` pairs.
+- **Conflict guard**: Passing both URL and stdio flags errors out so we don’t guess.
+
+## Naming & Identity
+
+- `--name` wins when provided.
+- Otherwise we derive a slug:
+  - HTTP: `<host>` plus a sanitized path fragment (e.g. `mcp-linear-app-mcp`).
+  - STDIO: executable basename + script (`node-mcp-server`).
+- The inferred name is printed so you know what to reuse later (`mcporter auth <name>`).
+
+This name becomes the cache key for OAuth tokens and log preferences, so repeated ad-hoc calls still benefit from credential reuse.
+
+## Auth & Persistence
+
+- OAuth flows are allowed; successful tokens store under the inferred name just like regular definitions.
+- 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.
+
+## Safety Nets
+
+- Non-HTTPS endpoints require `--allow-http`.
+- For stdio commands we print a confirmation snippet the first time we see a new command unless `--yes` is present.
+- Missing transports or malformed combinations throw descriptive errors, pointing to `docs/adhoc.md` for guidance.
+
+## Follow-ups
+
+- Extend `mcporter config add` to leverage the same helper, making it the one-stop path from exploration to permanence.
+- Consider caching inference results so repeated URL calls automatically rehydrate the previous settings (env/cwd).