At 7:05 on a Friday evening in July 1981, the Hyatt Regency in Kansas City was hosting a dance. Between 1,500 and 2,000 people filled the atrium, and some stood on the walkways that hung over the lobby to watch. Then the fourth-floor walkway and the second-floor walkway beneath it fell to the floor. A Missouri appeals court later counted 114 dead.
The walkways failed where their beams met the steel rods holding them up. Those joints had a curious history. The structural engineer testified that he had meant the steel fabricator to design them. The fabricator had prepared its drawings on the basis that the engineer already had. The case has the rest.
Every piece in exactly one box
Break a big job into pieces you can hand out, and check that nothing falls between them.
That is the job of a work breakdown structure, or WBS. Start with what the project must deliver, split it into its main parts, split each part again, and keep going until every piece is something one team can plan, cost and own. NASA’s handbook, written for projects from research to spacecraft, says the structure should be organized around products, not around the org chart, and “should represent the entire scope of work for the project.” At the bottom sit work packages, and each one, the handbook says, “is assigned to a single organizational element.”
The splitting is the easy part. The value is in the checking. NASA asks every project to keep a WBS dictionary describing what each piece contains, so as to ensure “that all work scope has been identified and to eliminate duplication and overlap of work assignments.” Two pieces that both claim a job waste effort. A job that no piece claims doesn’t get done.
The joint between two boxes
At the Hyatt, the connections sat right on a boundary. Designing them, the court wrote, was the structural engineer’s responsibility, though by custom the engineer could hand it to the fabricator by showing that on the drawings. “These drawings did neither.” So each firm treated the work as the other’s.
Then the job changed. To make fabrication easier, the fabricator proposed hanging the lower walkway from the upper one, which doubled the load on the upper joints. The engineers approved it without the calculations, the court found. NASA’s handbook expects the breakdown to be revised whenever the scope of work changes. A change like this is exactly when to ask again who owns what.
None of this was the only failure. The National Bureau of Standards found that even the original joint wouldn’t have met the building code. A clear breakdown doesn’t make anyone’s work correct. It makes sure someone is answerable for checking it.
The boundaries are where pieces of work tend to go missing, which is why mature breakdowns give the joining work a box of its own. NASA’s standard structure includes an element for systems integration and testing, the work of making the parts fit together.
Imagine a family moving house. The list says: pack the kitchen, book the van, clean the old flat. One person takes each. Nobody writes down “return the keys,” so on the last day each of them may assume someone else did it, and the deposit could be held up.
Breaking down work for AI agents
Splitting work among AI agents runs into the same problem, sometimes faster. In 2025 Anthropic described a research system in which a lead agent breaks a question into subtasks and hands them to other agents. Early versions gave short instructions like “research the semiconductor shortage.” The instructions were often too vague. One subagent looked into the 2021 automotive chip crisis while two others duplicated each other’s work on 2025 supply chains. “Without detailed task descriptions,” Anthropic wrote, “agents duplicate work, leave gaps, or fail to find necessary information.”
Its fix reads like a work package: each subagent “needs an objective, an output format, guidance on the tools and sources to use, and clear task boundaries.” Whether a person or a model is doing the splitting, the same checks apply: do the pieces add up to the whole job, does each have exactly one owner, and who owns the joins?
At the Hyatt, the drawings had a place for every beam and every rod. What they didn’t have was a clear owner for the joint between them.