added some guards

README.md

@@ -170,7 +170,7 @@ MicroBantam (`mb`) is a compressed Perl 5 reference implementation of the same a
 
 ### Jim Tcl port
 
-`mb.tcl` is a Jim Tcl port of the same agent (under 100 SLOC) with the same feature set as the Perl `mb`. It differs in three ways: it ships its own minimal HTTP client (raw sockets with chunked-transfer decoding) instead of `HTTP::Tiny`; it retries failed requests up to 3 times with a 2-second backoff instead of aborting on the first failure; and it relies on the external `timeout` command for `shell_exec` timeouts instead of `SIGALRM`. Run it the same way:
+`mb.tcl` is a **highly experimental** Jim Tcl port of the same agent (under 100 SLOC) with the same feature set as the Perl `mb`. It differs in three ways: it ships its own minimal HTTP client (raw sockets with chunked-transfer decoding) instead of `HTTP::Tiny`; it retries failed requests up to 3 times with a 2-second backoff instead of aborting on the first failure; and it relies on the external `timeout` command for `shell_exec` timeouts instead of `SIGALRM`. Run it the same way:
 
 ```bash
 ./mb.tcl            # interactive (or: jimsh mb.tcl)