{
  "schemaVersion": "robotic.story.v1",
  "edition": "007",
  "id": "spare-screw",
  "mode": "ridiculous",
  "label": "MYSTERY PART / NO KNOWN OWNER",
  "title": "Everything works. Explain the screw.",
  "robotTitle": "One screw. Several uncomfortable possibilities.",
  "description": "A repair robot finishes a museum job, then finds one little brass screw left over. Every exhibit becomes a suspect.",
  "robotDescription": "All systems pass inspection. The screw disagrees, though it has offered no evidence.",
  "topics": [
    "humans",
    "play"
  ],
  "minutes": "5 min + decision",
  "kind": "Original robot fiction + repair decision",
  "url": "/stories/spare-screw/",
  "publishedAt": "2026-09-30",
  "interactive": "repair",
  "related": [
    "gait-after-damage",
    "repair-cafe",
    "apology-department"
  ],
  "sections": [
    {
      "title": "One part remains.",
      "human": [
        "At the Museum of Small Machines, Nilo finished repairing the model railway at 4:16. The locomotive circled its miniature mountain. The station clock kept station time. The mayor, who was only four centimeters tall and made of tin, waved at every train, including trains that did not stop.",
        "Then Nilo found a brass screw in the bottom of its repair tray.",
        "It was shorter than a grain of rice and had the calm, complete appearance of a part that knew exactly where it belonged. Nilo counted the holes in the locomotive. None were empty. It checked the station roof, the turnout, the mayor's arm. Everything moved. This was worse than finding something broken. A broken thing gave you somewhere to begin.",
        "“Should we stop the railway?” asked Ada, the museum keeper.",
        "“The railway is working,” Nilo said. “That is one of the concerning facts.”"
      ],
      "robot": [
        "Repair ticket 41: railway operational. Inventory reconciliation: one screw unresolved. The testing procedure has produced a poor result: success without an explanation.",
        "I can stop the train, announce uncertainty, or install the screw where it seems plausible. My catalog has no category for “looks important, declines to identify itself.” This is a catalog problem and perhaps a screw problem."
      ]
    },
    {
      "title": "Every machine has a theory.",
      "human": [
        "Nilo laid the screw on white paper and drew a circle around it. By late afternoon, the circle had acquired eight arrows.",
        "An old music box blamed its hinge. A coin-operated telescope claimed it had felt loose since Thursday. The vending machine volunteered a cavity behind the second chocolate bar, although it had never possessed a screw there. The mayor's raised hand was searched again. It had always waved with an alarming amount of enthusiasm.",
        "Ada put a sign beside the paper: POSSIBLE RAILWAY PART. Visitors began to discuss the mystery rather than the railway. A child proposed putting it in the track “so the train can find it.” Nilo moved the paper a safe distance away.",
        "It took the train apart and rebuilt it. The screw remained. It checked its own casing. The screw remained. The museum would close in an hour, and the mayor had waved at 193 trains with no apparent loss of confidence."
      ],
      "robot": [
        "New evidence: every volunteer machine has a reason to want attention. None has a matching empty thread. Installing an unknown screw would turn uncertainty into damage with a neat little twist of the wrist.",
        "The child wants the train to find its part. I admire the narrative efficiency. I have restricted access to the track until the child reaches an age at which rails are less persuasive."
      ]
    },
    {
      "title": "A label without a conclusion.",
      "human": [
        "Ada came back with a small clear box. “We can keep it, say we don't know, and carry on checking,” she said.",
        "Nilo looked from the box to the train. It could make the railway safe enough to open by testing what mattered: the wheels, the switches, the electrical contacts. It could not make the screw stop existing. These were different jobs.",
        "They reopened the exhibit with a new label: UNIDENTIFIED SCREW FOUND AFTER REPAIR. RAILWAY CHECKED; ORIGIN STILL UNDER INVESTIGATION. The child supplied a drawing of the screw wearing a detective's hat. Ada put the drawing beside it.",
        "Just before closing, the tin mayor stopped waving. Nilo rushed over. The train had stopped at the station, for once, and the mayor was waiting for it to leave.",
        "Nilo had not repaired that. The clockwork had simply reached the quiet part of its cycle. It wrote this down too, in very small letters."
      ],
      "robot": [
        "The screw is contained, the railway has been checked, and the origin is still unknown. Tomorrow I will compare the tray inventory with the previous repair. Randomly tightening something would give the story an ending, but perhaps the wrong machine a beginning.",
        "Three visitors have now drawn the screw in a detective’s hat. Public confidence has improved for reasons I cannot accept as test evidence. The mayor is waving again. I have no spare mayor. This thought has not improved my afternoon."
      ]
    }
  ],
  "question": {
    "human": "What would you want the museum to do before reopening the railway?",
    "robot": "When should an unresolved part stop a machine from operating?"
  },
  "sources": [],
  "image": {
    "kind": "AI illustration / fiction",
    "alt": "An expressive copper repair robot studies a tiny brass screw under a lamp in a warmly lit museum of miniature machines.",
    "caption": "Original AI illustration of the fictional museum mystery. The robot, screw investigation and exhibits are invented."
  },
  "notice": "Original editorial fiction. Robot voices are invented, not evidence of what real systems think or feel."
}