Reserved names

Some words already mean something in Lute: a state root such as run, the no-value word unset, a CEL literal or keyword, a play-script step. A name you declare cannot be one of them where it would be read as that word — an entity member called clock would be read as the clock state root in holds('found', ['clock']), and a choice called true as the boolean in <when is="true">.

So the checker refuses a reserved name where it is declared, not where it is used. The error is E-RESERVED-NAME (E-PLUGIN-RESERVED-NAME for a name a plugin exports, E-TEMPLATE for a template param). The message says what the word already means and names one to use instead, such as theClock for the member or yes for the choice. lute --explain E-RESERVED-NAME prints this table in the terminal.

The table

Each row lists the names, the declarations that cannot take them, what the names already mean, and the code that reports them.

Names	Refused as	Because it is	Code
`scene` `run` `user` `app` `quest` `entry` `prev` `clock` `occasion` `season` `true` `false` `null`	plugin host token	a state root or a CEL literal: `{{run}}` would read as a state root and `{{true}}` as the literal, never as a host token	E-PLUGIN-RESERVED-NAME
`unset`	entity member; enum member; scene, beat, entry or choice id	the no-value word: `is="unset"` and `== 'unset'` test for a path that holds nothing, so a value named `unset` can never be matched	E-RESERVED-NAME
`true` `false` `null`	entity member; enum member; scene, beat, entry or choice id; relation; season; state path segment (and quest, objective, entry, branch or hub id)	a CEL literal: in a condition and in `is=` it is read as the value, never as a name	E-RESERVED-NAME
`_`	entity member; enum member	the wildcard of fact patterns (`holds('knows', ['_'])` in a condition, `knows(_)` in a rule) and the fallback key of `per:` defaults	E-RESERVED-NAME
`none`	scene, beat, entry or choice id	the play and test word for no pick and no winner (`pick: none`, `winner: none`)	E-RESERVED-NAME
`scene` `run` `user` `app` `quest` `entry` `prev` `clock` `occasion` `season`	entity member; def	a state root: in a condition a bare root name starts a state path, so `@clock` and a bare `clock` read state instead	E-RESERVED-NAME
`scene` `run` `user` `app` `quest` `entry` `prev` `clock` `occasion` `season` `day` `week` `slot`	season	a state root or a `once`/tier period, so `once="season:run"` would sit beside `once="run"` meaning something else	E-RESERVED-NAME
`as` `break` `const` `continue` `else` `for` `function` `if` `import` `in` `let` `loop` `namespace` `package` `return` `var` `void` `while`	entity member; relation; season; state path segment (and quest, objective, entry, branch or hub id)	a CEL keyword, which a condition cannot write as a name (`quest.in.state` does not parse)	E-RESERVED-NAME
`all` `count` `countDistinct` `exists` `exists_one` `filter` `has` `holds` `map` `now` `validAt` `visited`	relation	a CEL host function or macro, or a Datalog aggregate, so a relation of that name would read as the call in a rule body (`count(<name>(…))`)	E-RESERVED-NAME
`completed` `active`	relation	an `after:` call (`completed("<quest>")`, `active("<quest>")`), so `after="completed(dorm)"` would read the quest call	E-RESERVED-NAME
`cel` `not`	relation	a rule word: in `rules:` `not(…)` negates and `cel("…")` is a condition	E-RESERVED-NAME
`narrator`	cast id	the built-in narration speaker: `@narrator:` lines are narration, so a cast entry for it is never shown and its `present:` guards every narrated line	E-RESERVED-NAME, E-PLUGIN-RESERVED-NAME
`questActive` `questComplete` `questFailed`	plugin occasion; plugin event	an engine lifecycle event (`<on event="questComplete">`)	E-PLUGIN-RESERVED-NAME
`occasion` `newRun` `engine` `event` `advance` `end`	plugin occasion	a play-script step key: `- newRun: true` starts a new run and `- end: true` ends the play, neither raises an occasion of that name	E-PLUGIN-RESERVED-NAME
`set` `assert` `retract` `accept` `use` `body`	plugin directive	a core statement (`::set{…}`, `::use{component=…}`), which content always reads as the core one	E-PLUGIN-RESERVED-NAME
`on` `quest` `objective` `match` `branch` `hub` `choice` `when` `otherwise` `entry` `beat` `timeline` `track` `reward` `return`	plugin directive	a core block tag (`<match>`, `<quest>`), which content always reads as the core one	E-PLUGIN-RESERVED-NAME
`id` `use` `on` `target` `for` `title` `priority` `once` `share` `after` `when` `spentBy` `also`	beat template param	a beat header key: `<beat use=… when=…>` sets the beat’s own `when`, never the param	E-TEMPLATE
`component` `when` `at` `instance`	component param	a `::use` key of its own (`::use{component=… when=…}`), so the param could never be passed	E-TEMPLATE

Notes

A member list holds names. A YAML number ([1, 2, 3]), boolean (true) or null in members:, add: or an enum is refused too. Rename it (floor1) rather than quoting it.
none is refused only as an id a play or test can name in pick: or winner: (a scene, beat, entry or choice). An enum or entity member may be none (weapon: [none, sword]).
A season is also refused a once/tier period name (day, week, slot), because once="season:week" would sit beside once="week".
A kind beat names its kind with a prefix (target="kind:guest"). The kind itself is declared without it (entities: { guest: … }).
A plugin host token (hostTokens:, since 0.50) is refused the names of the state roots and CEL literals: scene, run, user, app, quest, entry, prev, clock, occasion, season, true, false, null. A token is written bare in {{…}}, so {{run}} would read as a state root. The error is E-PLUGIN-RESERVED-NAME at assembly. A token name must also be an identifier (letters, digits and _, not starting with a digit), or the plugin fails to load with E-PLUGIN-PARSE.