L1 guide: the shell bridge

How module code becomes shell surface.

Registering a command from L1

l1_ext_shell_register_command_ex(name, fn, help, wp_tag)

fn receives the argument string, returns 0/non-zero. The tag shows in help -w. The table holds 256 commands (233 registered today) - registration is refused with a clear error when full, never silently.

Enumerating (the TUI pattern)

l1_ext_shell_list_commands_a_z()
l1_ext_shell_list_commands_by_wp()

The TUI command bridge (tui/tui_cmd.c) enumerates the table through exactly these and renders the launcher - the reference consumer. Any L1 module may do the same.

Built-ins and jobs (l1_wp8cd.h)

shell_register_builtin / shell_unregister_builtin (the self-test path uses these), shell_run (the interactive loop), job_create / job_list / job_control for background jobs, and tool_register to embed an ELF payload the shell can run.

The contract

• Names are ASCII, lowercase, dotted/multi-word allowed (mkfs.fat32, health export are real registrations).
• Help is one line; argument errors print usage: ....
• Commands are never removed once shipped (CONTRIBUTING.md).