bacnet-ops

The UI-free operations core of the bacnet tool in the Rusty BACnet workspace. The one-shot commands, the terminal UI and the MCP server (bacnet-mcp; see docs/design/mcp.md) share it, so they read targets, values and devices the same way and obey the same request limits.

• class: what each command does to a device (read, write or device management), the table the front ends' safety levels share.
• target and destination: the target grammar (192.168.1.10, 1234, 2:1234, bip6:0x0004D2, mstp:5, ...) and how a target becomes a service destination, routed through the client's discovery table.
• parse: the object, property and value grammar (ai:1, present-value[3], 72.5@8).
• format and label: property values as display text, and how objects, properties and command priorities are named.
• limits: a global request-rate cap, one outstanding confirmed request per device, optional rates per network, and per-caller accounts with their own token buckets.
• decode: frames of the tapped links (B/IP, B/IPv6, BACnet/SC, MS/TP), NPDUs and APDUs as one-line summaries and trees of fields with their octet ranges, with no traffic.
• engine: the read operations over a BACnetClient: properties (by ReadPropertyMultiple, falling back to ReadProperty), the object list, a device summary, trend log pages, alarms and the alarm and enrollment summaries, Who-Is and Who-Is-Router-To-Network with the discovery table, and the BBMD table reads.
• bbmd: B/IP broadcast management tables as plain data, the survey that follows each BDT to the BBMDs it lists, and the consistency matrix over them (one-way entries, missing own entries, mismatched masks).
• watch: the watch hub. One managed COV subscription per point (finite lifetime, renewed, cancelled when the last listener leaves) or a poll every 10 s or slower when the device refuses COV, however many listeners share it; it keeps the latest values, so reading a watched point sends nothing, and folds bursts of notifications, counting what it folds.
• safety: the write-safety core the terminal UI and the MCP server share: session levels, confirmation tiers, the write preview, the crash-safe ledger of pre-images, the redacted append-only audit log, the workspace lock, and the engine half of a write (read again, refuse a stale preview, record, send, settle, revert).

It is a hosted crate: it needs std and Tokio, and has no terminal or MCP dependency. Its sc-tls feature lets the address formatter recognise a BACnet/SC link; test-support adds frame builders for the CLI's decode tests and is not a stable API.

The API follows the needs of the bacnet tool and changes with it before 1.0.