The F-key model is the operator interface of os-console. Each F-key slot hosts a Cartridge — a self-contained module compiled into the binary that owns its rendering, keyboard handling, and lifecycle. Understanding the slot assignments and how each Cartridge works lets you move efficiently between platform functions without leaving the terminal.

For the Cartridge trait and how slots are compiled in, see app-console-keys. For navigation fundamentals, see navigate-console-tui.

Default slot assignments

F-key	Cartridge	Primary function
F3	Email	Read and compose messages; see app-console-email
F9	SLM	Local inference and Doorman health dashboard; see app-console-slm
F12	Input Machine	Human-verified record entry; mandatory per SYS-ADR-10; see app-console-input

Slots not listed above are reserved or unloaded. A dimmed label in the navigation strip indicates the slot is unloaded in the current session.

How a Cartridge works

A Cartridge is compiled into the os-console binary. It is not a plugin or runtime script. When you press an F-key, the binary hands control to the Cartridge registered for that slot.

Each Cartridge:

• Renders its own full-screen view in the slot area
• Handles keyboard events for that slot
• Reports to the status bar which slot is active
• Connects to the relevant platform service (email, SLM, ledger) using the active MBA connection

A Cartridge that cannot reach its backing service shows a status indicator in the slot area rather than failing silently.

Using the Email Cartridge (F3)

1. Press F3 to open the Email Cartridge.
2. The inbox list appears showing unread counts and sender summaries.
3. Navigate with arrow keys; press Enter to open a message.
4. Press c to compose a new message.

Outbound messages route through service-email. Direct SMTP connections are not used — the Cartridge acts as a Comm Diode, applying tenant communication policy before sending.

For detail on the email flow, see app-console-email.

Using the SLM Cartridge (F9)

1. Press F9 to open the SLM Cartridge.
2. The Doorman health dashboard shows which inference tier (A, B, or C) is active and the entity count from the DataGraph.
3. Press R to manually refresh the health status.
4. Submit a prompt at the input line. The response streams into the slot area.

All inference requests route through Doorman. No prompt data leaves the operator's hardware.

For the inference architecture, see app-console-slm and doorman-protocol.

Using the Input Machine (F12)

The F12 slot is the human-in-the-loop gate required by SYS-ADR-10. It is the only path through which an operator-verified record can enter the WORM ledger.

1. Press F12 to open the Input Machine.
2. Review the record or document displayed for verification.
3. Confirm or reject using the labelled key bindings shown in the navigation strip.

A confirmed record is written to the ledger immediately. A rejected record is routed to quarantine.

For the design rationale, see app-console-input and worm-ledger-architecture.

Key takeaways

• Each slot is compiled in at build time — there is no plugin runtime or slot hot-swap
• A Cartridge that loses its backing service degrades gracefully and shows a status indicator
• F12 cannot be reassigned; it is structurally the human-verification gate for the ledger
• The Comm Diode model in F3 means email routing applies tenant policy — you cannot bypass it from within the Cartridge

See also

• app-console-keys — chassis architecture, Cartridge trait, status bar components
• app-console-email — Email Cartridge: inbox, reading, compose, and plain-text mode
• app-console-slm — SLM Cartridge: Doorman dashboard and local inference
• app-console-input — Input Machine: the F12 human-verification gate
• navigate-console-tui — overall TUI layout and slot navigation
• worm-ledger-architecture — the ledger that F12 writes into