EN Studio Check

Check: validator, solver, critical path, heat, health, coverage

Français · Type: how-to + reference · 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: solver-scope

The Check tab runs the validator and the solver after every save and lays out what they found, with the world map, the puzzle graph, the content lint, the playtests and the storyboard coverage, each the same text an MCP tool returns.

What you get

A game you know can be finished from New Game (or from a checkpoint), and the list of what blocks it when it cannot: validation errors, dead ends, items never used, rooms never reached, rules nothing can trigger.

Context and versions

The local Studio, in the engine repository or a created project. True from 4.2.1. The demo Studio runs Validate and Solve in the page; the screenshot and the playtests need the dev server. The same checks on the command line: Checking your game.

Prerequisites

• The Studio running (overview).
• For Screenshot only: Playwright and its Chromium (doctor).

Where to run the commands

In the browser, on the Check tab. Each panel names the command that gives the same result in the engine repository or the created project.

Steps

1. Let it run. The validator and the solver run after every save; the tab's badge shows the result. Run again runs them by hand. Solve from picks the start: New game, or a checkpoint (an unknown checkpoint is a 400).

2. Read the solver. The validator's errors and warnings first, then the solver: finished or not, the path it found, the rooms reached, what was unlocked, the items never used and never obtained, and the dead ends (room, inventory, and the path that leads there).

3. Ask the puzzle graph (below) what hangs on a puzzle before you change it.

4. Screenshot renders a room at a checkpoint, the editor's overlays hidden, into .cache/studio/<game>-<room>[-<checkpoint>].png.

The panels

Panel	What it shows	Same as
Validator	Errors and warnings of the content	npm run validate, the validate tool
Solver	Finished or not, the path, rooms reached, unlocked, items never used or obtained, dead ends	npm run solve, the solve tool
World	The world map: rooms, exits, gotos; unreachable rooms and exits with no way back in red	the world_graph tool
Content report	What each room, item and character amounts to	npm run validate -- --report, the content_report tool
Puzzles	The puzzle graph (below)	npm run page:puzzles, the puzzle_graph tool
Solver health	Engine runs, actions skipped, no-ops, actions per state, the dimensions that split the states most, and the warnings a designer acts on: independent dimensions (a checkpoint between them would cut the states), a room with runaway branching	npm run solve -- --profile (the full profile under Full profile)
Playtests (dev server only)	The sessions of games/<id>/playtests/ replayed and summed up	npm run playtests, the playtests tool
Content lint	Errors, warnings and info, each a link into the Rooms tab	npm run lint, the lint tool
Storyboard coverage	The storyboard checked against the content	the storyboard_coverage tool
Changes between revisions (dev server)	What changed between two revisions	Semantic diff

The puzzle graph

Every rule, topic, script and listener, with what it needs (grey arrows, dotted when it is read inside its commands) and what it produces (green) or consumes (red). Tap an item, flag, prop, place or event for its card: acquired by, used by, requires first, unlocks, downstream, and why the solver keeps it (critical, world, visible or dead, with the chain to the end), the same text the puzzle_graph tool returns.

Two toggles above the graph:

• Critical path fades everything that does not lead to the end, a goal or an invariant.
• Heat colours each rule, topic, listener, script and room by how many times the solver went through it. Its selector can colour the nodes by the players' sessions (the playtests) instead of the solver's runs.

Reading it before you change a puzzle. The card of the pantry key in the demo reads: acquired by give bouquet + seller; used by use key + pantry and the finale's goal; requires first bouquet, flowers_done, bouquet_given; unlocks the pantry and the end. Remove the bouquet trade and the card tells you what breaks before the solver does. The overview lists three smells:

• a thing read but never produced (a flag nobody sets);
• a thing produced but never used (a flag or item that leads nowhere);
• a flag set only by actions that already need it: it can never become true (the validator warns too).

How to design puzzles with it: Puzzle design.

Limit · solver-scope The solver says whether a way to the end exists from the start you picked; its search is bounded, and a truncated search says so. What a result lets you conclude, and the exhaustive proof (--prove): What the solver proves.

Expected result, and how to check it

The tab's badge is green; the solver says it finished, with no dead end; the lint has no error. On the command line, in the engine repository:

# in the engine repository (or a created project: npm run verify)
npm run validate && npm run solve

Common errors

Symptom	Cause	Fix
Screenshot: 501 unavailable	Playwright or its Chromium is missing	npm i -D playwright && npx playwright install chromium
400 for Solve from	The checkpoint is not in the game	Pick one of the list
The solver does not finish	A dead end or an unreachable goal	Read the dead ends and the puzzle graph's card of the missing item
No Playtests panel	No session in games/<id>/playtests/, or the demo	Add sessions (Playtests)

Files or data changed

None in the game. Screenshots go to .cache/studio/.

References

• src/studio/check.ts; the engine's tools in src/engine/tools/.
• Checking your game, Solver options, MCP tools.

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