a real action keyword MISSING ITS REQUIRED ARGUMENT silently writes a dead button

[marclehane-creator]

The 0.20.0 report covered an invented token degrading to Forms$NoAction. The sharper
0.21.0 form is that a valid, documented keyword given without its required argument
degrades identically — so the failure now sits on the happy path of the feature this release
added.

written	check --references	exec	stored
Action: OPEN_LINK 'https://example.com' (correct)	Check passed!	Created page	Forms$OpenLinkClientAction ✅
Action: OPEN_LINK (keyword, no argument)	Check passed!	"Created page", exit 0	Forms$NoAction
Action: TOTALLY_MADE_UP (invented)	Check passed!	"Created page", exit 0	Forms$NoAction

mx check is 0 in every row, because a no-action button is legal Mendix. The grammar has a
fixed action vocabulary (mxcli syntax page --json: SAVE_CHANGES, CANCEL_CHANGES,
SIGN_OUT, OPEN_LINK, …), so an unrecognized or under-specified token should be a parse
error rather than a silent degrade to NoAction.

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mxcli 0.21.0 (mxcli-windows-amd64.exe, 2026-09-06 build), Mendix 11.11.0 / 11.12.x, Windows 11. Each item was re-measured on a fresh app with a control of the same construct type, and every mx check verdict is the literal The app contains: N errors. line. We keep the full register with repros in our repo; happy to share more detail.