Loaf Manifest Field Reference

Every field in loaf.yaml, with its type, constraints, and rationale.

Schema: schemas/loaf.schema.json Template: templates/loaf.yaml.template

A Loaf is the attachment and interconnect layer that lets Slices operate together as one BREAD. See Loaf for the concept.

Top-Level Required Fields

Field Type Description
schema_version string (M.m) Schema version this file conforms to
id string Unique ID: loaf-{name}, pattern ^loaf-[a-z0-9-]+$
name string Human-readable display name
status enum concept · prototype · validated · released · deprecated
role enum backplane · controller · hybrid
summary string One-line purpose
version object hardware, firmware (nullable), manifest
compatibility object loaf_spec, slice_spec, crumbs_protocol
hardware object Physical description
electrical object Power in, rails out
interconnect object Slice attachment and bus
artifacts object Paths to schematic, PCB, docs
license object Per-domain licences
repository object Repo URL
metadata object created, updated, tags

id is derived from the repo name: Loaf_x004 → loaf-x004.

role

The field that distinguishes the two kinds of Loaf.

Value Meaning
backplane Provides Slice attachment. interconnect.slice_slots > 0.
controller Provides the controller interface and chains onto a backplane. No Slice slots of its own — interconnect.slice_slots is 0.
hybrid Both: hosts a controller and provides Slice slots.

A controller alone is not a Loaf. It qualifies only because it also provides the attachment/interconnect role — in the controller case, by chaining onto a backplane and carrying the bus.

Worked examples:

  • Loaf_x004 — backplane, 4 slots, no controller, barrel-jack power in.
  • Loaf_ESPT — controller, 0 slots, hosts an ESP32 Thing Plus, chains onto x004.

interconnect

This is what makes a board a Loaf rather than a carrier or a power board. Required.

Field Type Description
slice_slots integer ≥ 0 Slice attachment positions. 0 for a controller Loaf.
bus.type string e.g. i2c
bus.connector string e.g. slice-bus-10pin
bus.signals string[] Signals carried, e.g. +12V, GND, SDA, SCL, E_STOP
chaining.supported boolean Whether this Loaf connects to another Loaf
chaining.connector string | null e.g. 1x10-2.54mm

slice_slots: 0 with chaining.supported: true is the controller-Loaf shape: it carries the bus but does not terminate it in a Slice.

hardware

Field Type Description
controller object | null null for a passive backplane
controller.type string dev-board-socket · embedded · external
controller.form_factor string | null e.g. thing-plus
primary_ic object | null Manufacturer and part number of the defining IC
hw_gen_current integer Current hardware generation
hw_gen_supported integer[] Generations this board interoperates with
pcb.layers integer Copper layers. Must match the board; the KiBot config is chosen from it.
pcb.dimensions string e.g. 180mm x 162mm
connectors object[] ref, type, purpose
mounting object pattern, hole_size, inset
enclosure object | null supported, path

electrical

Field Type Description
input_voltage string Required
logic_voltage string | null  
rails object[] Rails the Loaf distributes: name, voltage, max_current, source
protection object reverse_polarity, input_esd, fuse

rails is the Loaf’s distinguishing electrical duty: a Slice consumes power, a Loaf distributes it. Record where each rail comes from (source), because that is what fails.

Remaining sections

firmware, artifacts, manufacturing, validation, safety, related, maintainers, license, repository, metadata mirror slice-manifest-spec.md, except:

  • firmware is nullable — a passive backplane has none.
  • related.compatible_loaves records which Loaves chain together.

Validation 

python3 scripts/validate_manifest.py loaf.yaml

The schema is auto-detected from the filename. CI runs this via validate-manifest.yml.