Last-Mile Delivery Assignment

Two objects arrive together: a package with priority, weight, needsSignature, distanceFromDeliveryPerson, and deliveryDeadline, and a deliveryPerson with skills, remainingCapacity, and collectSignatureEquipped. The whole graph scores this one candidate pairing rather than searching a pool.

Compatibility scoring works through requirement-skill pairings with a first hit policy, so the strongest match rows sit on top. An 'express' package over 20kg paired with a courier whose skills contain 'heavy_lifting' scores 10 with priorityLevel 'high', express with 'express_certified' scores 8, standard fragile freight matched to 'fragile_handling' scores 7, standard over 15kg with 'heavy_lifting' scores 5, a needsSignature package with a collectSignatureEquipped courier scores 4, and the catch-all grants a baseline 2 with 'low'.

Ordering rows by the difficulty of the requirement is the practical logic: express-plus-heavy is the hardest package to place, so finding a fully qualified courier is worth the most points. Skill flags like signature equipment and heavy-lifting map directly to real courier constraints, where handing a signature-required parcel to an unequipped driver produces a failed delivery attempt, and the point values themselves are tuning choices for the 15-point assignment bar downstream.

Score assembly happens in one pass: distanceScore is 10 - min([round(package.distanceFromDeliveryPerson / 2), 8]), so proximity decays with distance but never goes below 2; capacityFactor pays 5 only when deliveryPerson.remainingCapacity covers package.weight; and slaFactor doubles from 3 to 6 when the deliveryDeadline is under 7200 seconds away, boosting urgent packages. These add to matchScore as totalScore, and recommendedAssignment becomes true at 15 or more, the single boolean the switch routes on.

Assignment forks on recommendedAssignment == true: qualifying pairings flow to automatic assignment while the default branch sends everything else to manual review. Keeping the threshold decision in the expression and only the routing here means the 15-point bar can be tuned without touching the branch structure.

Successful matches get an assignmentStatus of 'assigned' plus an assignmentDetails record tying deliveryPerson.id to package.id with the achieved assignmentScore. The estimatedArrival adds package.distanceFromDeliveryPerson * 180 seconds to the current time, effectively assuming three minutes per kilometer, which gives dispatch a concrete ETA to publish rather than just a match confirmation.

Rejected pairings are parked with assignmentStatus 'pending' and a reason, 'Score too low for automatic assignment' when totalScore is under 15. The suggestedActions list, try a different delivery person, wait for a closer one, or escalate to the dispatch manager, turns the rejection into a queue item a dispatcher can act on instead of a dead end.