Motorway 0x4

Motorway 0x4 is the sweet spot of this pack: a four-lane off-ramp, and the four values it pulls are almost always model, positive, negative and latent - exactly what a KSampler wants. In the pack's own Example.json, a 0x4 is the node that feeds the sampler, and honestly it's the ramp that makes the whole bus idea click.

This comes from agilly1989's ComfyUI_agilly1989_motorway, a key-value bus ("pipe") for ComfyUI. Everything rides one MOTORWAY 🚌💨 wire; nodes store values under string keys and pull them back out later. Same goal as rgthree's Context nodes - fewer wires, a cleaner graph - but where Context bundles a typed object, the Motorway is an any-typed bag.

How it works

Motorway NxB exposes B keyed outputs. Type model, positive, negative, latent into the four _key boxes, and each matching value appears on the ANY (A..D) outputs as type *, ready to plug straight into the sampler's four inputs. The bus is cloned at every hop - a snapshot, not in-place mutation - and keys are exact strings, SHA-256 hashed internally. Last write wins on duplicates.

A typical bus flow: MotorwayStart → a 4x0 on-ramp stores the checkpoint trio and a latent → a couple of 0x1s hand clip to the prompt encoders → a 2x0 stores both conditionings → this 0x4 pulls all four sampler inputs off the bus in one shot. That's the pattern the example workflow lives on.

Inputs and outputs that matter

• MOTORWAY 🚌💨 (required) - the bus.
• ANY_(A)_key through ANY_(D)_key (optional) - the four keys to pull.
• Outputs: MOTORWAY 🚌💨 plus ANY (A) through ANY (D).

Blank keys are fine; unused outputs just dangle.

Installing

cd ComfyUI/custom_nodes
git clone https://github.com/agilly1989/ComfyUI_agilly1989_motorway

or ComfyUI Manager → "ComfyUI_agilly1989_motorway", then restart. No pip deps, no model files.

Where people get burned

• 'MotorwayClass' object has no attribute 'hash_' - the classic. One of the four keys isn't on the bus yet, usually because the write happens after this node in the graph, or a key string differs by a space.
• Sampler receives nothing - check that positive/negative were actually stored (the 2x0 after the encoders), not just typed into a widget somewhere.
• Beta. The README literally opens "CURRENTLY IN ACTIVE DEVELOPMENT (BETA)! IF THINGS BREAK ITS BECAUSE I BROKE IT." Flows between versions can and do break; pin what you rely on.

If you're evaluating the pack at all, load Example.json - the 0x4 feeding the KSampler is the moment the design makes sense.