Language and objectives

Français · Type: how-to · Audience: author · Context: local Studio · Status: ready · Applies from: 4.2.1

The local Studio · contract: stable · verified by CI (support matrix of 4.4.0, 2026-10-23): Chromium end to end (the Studio's checks); Windows: the unit suite only · automated checks: jobs e2e, windows; CI plan e2e, windows; 2 test files · people's passes: studio-hero-matrix not run (#238) · known limits: game-file-objectives-only

The Language tab shows the game as the tools see it: its objectives first, editable through forms generated from their schema, then its IR, the game's logic as data with the file:line that writes each piece.

What you get

An objective added or changed in the game file from a form, previewed as a diff, validated before it is written; and the place in the code of every room, rule, topic, listener and script.

Context and versions

The local Studio, engine repository or created project. True from 4.2.1 (the write is judged before it is written). What objectives are and how a game uses them: Chapters and objectives.

Prerequisites

The Studio running (overview).
A game file with defineGame({...}); a folder without one answers no defineGame({...}) in the game folder (404).

Where to run the commands

In the browser, on the Language tab. npm run ir runs in the engine repository.

Steps

Read the objectives. Each with its id, title, condition (done), parent, whether it is optional, and the file:line that writes it.

Edit an objective, or + objective. The form is generated from the objective's schema (src/studio/forms-gen.ts): each field with its description, the parent's id with the game's objectives as suggestions, the condition with the DSL's editor. A problem is named by file, id and field before anything is sent.

Preview the change shows the diff of the game file. Apply writes it: the server validates the game as it would be, and refuses the write when it adds an error, so an objective whose done can never hold is refused. The validator's errors are shown after. The header's Undo takes an applied change back (Preview, apply, undo).

Read the IR. Under the objectives: the rooms, entities, rules, topics, listeners and scripts, each with where it is written, and the whole IR as JSON. The same JSON comes from the command line:
```
# in the engine repository
npm run ir -- --json
```

Limit · game-file-objectives-only Through the Studio (and the set_value tool on @game), only the game file's objectives can be written: objectives, objectives.<id> or one of its fields. Any other path of defineGame({...}) is refused (400).

Expected result, and how to check it

The objective appears in the list with its new file:line; git diff shows the change in the game file; the Check tab still validates and solves.

Common errors

Symptom	Cause	Fix
A field is named in red before sending	The form's own check (file, id, field)	Fix that field
`refused: the edit adds N validation error(s): …` (422)	The objective breaks the game (a `done` that can never hold, an unknown parent)	Read the errors and change the objective
400 on a path other than `objectives`	Only objectives are written in the game file	Edit other fields in code

Files or data changed

The game file that holds defineGame({...}) (games/<id>/game.ts or where the game defines it).

Recovery or going back

The header's Undo, during the session; otherwise git.

References

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