Random Worldbuilding History Timeline Generator

Description

Place supplied fictional events in an inclusive Gregorian date interval while reserving predecessor-gap slack through a verified DAG.

A structured creative brief combines a supplied bank of fictional material with explicit sequencing, timing, or compatibility rules. IDs and tags make those constraints inspectable; they do not assess the artistic meaning or quality of a scene.

Place supplied fictional events in an inclusive Gregorian date interval while reserving predecessor-gap slack through a verified DAG.

When to use this tool

Use this generator to create reproducible worldbuilding history timeline cases from the supplied model or bank. Inspect the returned evidence before using cases in a test or exercise.

How to use the tool and how it works

Supply startDate, endDate, minimumPredecessorGapDays, events in the field shapes below. Set seed when you need an explicit replay.
Run the tool and correct any input error. For generated controls, distinguish a successful fixture containing an invalid case from failure to generate the fixture.
Read fictional, intervalDays, events, predecessorGaps. Use the conventions below and keep answer-bearing fields separate when presenting an exercise.

Validate distinct event IDs and predecessor references, topologically order the event DAG, and propagate latest permissible dates backward to reserve minimum-gap slack. Draw each date between its predecessor-constrained earliest offset and reserved latest offset, then sort the dated events and report predecessor gaps.^[1]

Delegated operations used for this result: topological sort. Their calculation or parsing conventions apply to the corresponding result fields.^[2]

Input field	Meaning and units	Accepted input
startDate	Start Date	Required. Text; minimum UTF-16 length 10; maximum UTF-16 length 10.
endDate	End Date	Required. Text; minimum UTF-16 length 10; maximum UTF-16 length 10.
minimumPredecessorGapDays	Minimum Predecessor Gap Days	Required. Safe integer; minimum 0; maximum 9007199254740991.
events	Events	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32.
events[].id	Literal identifier used to match records, independently of their display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 64.
events[].text	Text	Required. Text; maximum UTF-16 length 2048.
events[].predecessorIds	Predecessor Ids	Required. Array of Text; minimum UTF-16 length 1; maximum UTF-16 length 64.; minimum items 0; maximum items 31.
seed	Optional numeric seed; takes precedence over context randomness. Without either, use the fixed tool.io default seed.	Optional. Safe integer.

Output field	Interpretation	Returned shape
fictional	Fictional	Required. Boolean; exactly true.
intervalDays	Interval Days	Required. Safe integer; minimum 0; maximum 9007199254740991.
events	Events	Required. Array of Object; no unknown keys.; minimum items 1; maximum items 32.
events[].id	Literal identifier used to match records, independently of their display labels.	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 64.
events[].text	Text	Required. Text; maximum UTF-16 length 2048.
events[].date	Date	Required. Text; minimum UTF-16 length 10; maximum UTF-16 length 10.
events[].offsetDays	Offset Days	Required. Safe integer; minimum 0; maximum 9007199254740991.
events[].predecessorIds	Predecessor Ids	Required. Array of Text; minimum UTF-16 length 1; maximum UTF-16 length 64.; minimum items 0; maximum items 31.
predecessorGaps	Predecessor Gaps	Required. Array of Object; no unknown keys.; minimum items 0; maximum items 992.
predecessorGaps[].from	From	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 64.
predecessorGaps[].to	To	Required. Text; minimum UTF-16 length 1; maximum UTF-16 length 64.
predecessorGaps[].days	Days	Required. Safe integer; minimum 0; maximum 9007199254740991.
randomness	Replay metadata: source is seed or context; seed is the normalized 32-bit seed or null for a context source.	Required. Object; no unknown keys.
randomness.seed	Optional numeric replay seed; normalization and precedence are explained below.	Required. Safe integer. or Null.
randomness.source	Source	Required. Text; one of "context", "seed".

An explicit safe-integer seed takes precedence over injected context randomness and is normalized to an unsigned 32-bit integer. With no seed and no context source, replay uses the fixed tool.io default seed. A context source must return finite values from zero inclusive to one exclusive; its advancing state must be retained separately. randomness records the source and normalized seed, or null for context. These generators are not cryptographic random sources.

json

{
  "input": {
    "startDate": "2024-02-28",
    "endDate": "2024-03-02",
    "minimumPredecessorGapDays": 1,
    "events": [
      {
        "id": "arrival",
        "text": "The lantern ship arrives",
        "predecessorIds": []
      },
      {
        "id": "rebuild",
        "text": "The harbor beacon is rebuilt",
        "predecessorIds": [
          "arrival"
        ]
      }
    ],
    "seed": 42
  },
  "output": {
    "fictional": true,
    "intervalDays": 3,
    "events": [
      {
        "id": "arrival",
        "text": "The lantern ship arrives",
        "predecessorIds": [],
        "offsetDays": 1,
        "date": "2024-02-29"
      },
      {
        "id": "rebuild",
        "text": "The harbor beacon is rebuilt",
        "predecessorIds": [
          "arrival"
        ],
        "offsetDays": 2,
        "date": "2024-03-01"
      }
    ],
    "predecessorGaps": [
      {
        "from": "arrival",
        "to": "rebuild",
        "days": 1
      }
    ],
    "randomness": {
      "seed": 42,
      "source": "seed"
    }
  }
}

Limitations and assumptions

Dates are fictional Gregorian calendar dates inside an inclusive interval. Cycles, missing references and chains that cannot fit are rejected. Constrained sequential draws do not sample all feasible timelines uniformly.
A replay requires the same complete input and implementation. Randomized construction does not guarantee uniform coverage of every feasible output; finite samples can repeat unless a distinct-selection rule is explicitly stated.
The field tables state structural bounds; cross-field constraints and bounded search or output budgets also apply. Unknown keys are rejected where the object contract disallows them. Input errors are distinct from null fields and deliberate invalid controls in a successful output.

Alternative or Complementary methods

For a supplied example, inspect the returned construction or delegated check directly. To evaluate a consumer, also test cases chosen for its own boundaries; a generated finite corpus does not establish exhaustive coverage.

References

Tool behavior and example: Random Worldbuilding History Timeline Generator — tool.io
Calculation or validation: graph/topological-sort — tool.io

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