flutter_mcp_ui_runtime 0.7.2

Runtime for building dynamic Flutter UIs from JSON with lifecycle management, state handling, and MCP protocol support.

0.7.2 - 2026-08-07 — the alias is inferred from too

mediaPlayer opens src ?? source and 0.7.1 inferred the kind from source alone, so a document written with the legacy spelling pointed at an .mp3, inferred nothing, and fell back to video — the host was asked for the video capability and an audio-only one reported it absent. Both now read the same value. Reported by sbuilder against the published cut.

0.7.1 - 2026-08-07 — the spec states the standard, the runtime keeps reading the legacy

Backward compatibility is measured here, not asserted: compat_probe_test runs 577 documents from this workspace through the last pre-1.4 registry, the published one, and this tree. A document the published registry accepts and this one does not now fails the suite — widening is free, taking a form away closes bundles that are already in the field.

Result of that gate today: 0 documents lost, 57 gained (forms that were rejected at load and are accepted again).

Legacy values are declared, not advertised

The registry gained legacyValues:. Those spellings go into the schema — so a bundle carrying one still opens — and stay out of the prose, the generated tables and anything that offers an author a choice:

• linear.distribution — space-between / space-around / space-evenly
• qrCode.errorCorrection — L / M / Q / H
• codeEditor.theme — light / dark
• Color — the pre-M3 slot names (divider, foreground, textOnSurface, textOnPrimary, textOnSecondary, textOnBackground, textOnError). These now resolve as well as validate: each maps onto the M3 role it meant, so a document that used to load and paint nothing paints the right colour.

A new audit section (drift_audit §L) reports any spelling the runtime renders that the schema refuses, so this class cannot come back silently.

Declared defaults now say what the runtime does

drift_audit §M compares each registry default: against the literal the factory falls back to. Ten disagreed; in every case the implementation was left alone and the documentation corrected, because the default is what a document that says nothing already gets:

gauge.strokeWidth 20→10 · gauge.labelFormat {value}→{value}% · gauge.startAngle 135→-220 · gauge.sweepAngle 270→260 · heatmap.showValues false→true · signature.showGuide false→true · codeEditor.theme vsLight→dark · terminal.prompt $→$ · timeField.use24HourFormat true→false · timePicker.use24HourFormat false→true. (The last two disagree with each other; both are documented as implemented rather than unified, because unifying them would change screens that never named the property.)

Visible without declaring anything

Four changes alter what an existing document draws even if it declares none of the properties involved:

• chart — the entry reveal declared by options.animation.duration (default 1000 ms) now runs. options.animation.duration: 0 restores the instant draw.
• calendar — the month fits the box it is given instead of scrolling, and a month that begins on the week's first day no longer carries a leading week of the previous month.
• networkGraph — the graph is fitted to its box (placements were built around a fixed centre of 200,200) and each layout draws its own shape.
• codeEditor — Tab indents by tabSize instead of moving focus.

colorPicker keeps its preset swatches: the registry said pickerType: wheel while no implementation ever drew one, so the default is now palette — what every picker has always shown — and wheel / both are opt-in.

Also in 0.7.1 — validation that was declared but never applied

Additive only. A schema narrowing is a bundle break, not an authoring hint: the runtime validates documents at load, so a slot that stops accepting a value stops the bundles carrying it from opening. Nothing here narrows anything — measured, not assumed (see below).

A validation block written to 07_Security.md §7.2.1 produced no rules at all. The section publishes two shapes and says a runtime MUST support both. Shape B is an array keyed rule; this engine only ever read type, and its switch had no default, so an array in the published spelling parsed to an empty rule set — and an empty rule set validates everything. Shape A, the constraint object, was answered with "legacy validation format detected" and discarded. The workspace corpus holds 117 Shape B blocks, every one of them already in the rule spelling, so every declared constraint in it was inert: the field accepted anything, quietly, and nothing anywhere said so.

• rule is read, and type still is. Documents authored against the shipped engine keep validating; documents authored against the published spec start.
• Shape A parses. kind becomes the matching rule, maxLength and pattern become their own, and they compose — {kind: email, maxLength: 12} now rejects on either.
• phone, number, integer and date are implemented. §7.2.1 published them; the enum had no entry, so they parsed to nothing even under the right key. Each checks shape only: an empty value is required's business, so "optional, but must look like a phone number" stays expressible.
• An unrecognised rule or kind is now reported. A constraint nobody parses is one the author believes is running, and a typo used to be indistinguishable from a field with no rules.

This changes behaviour for existing bundles, deliberately. A form whose required rule was inert will start refusing empty input. The author declared that constraint; applying it is the fix, not a regression — but a bundle that had come to depend on the constraint not running will behave differently.

box.margin now takes the M3 spacing token, like padding. Both slots have always resolved it through the same helper; only the declaration was narrower, which made the token unauthorable rather than unrenderable. A token the theme does not declare produces no inset and is now reported once per distinct value — "16px" in a padding slot has always resolved to nothing, and saying so is the whole of the fix. The registry still accepts it: tightening that pattern would stop published bundles from opening.

Verified additive by differential: 20 value shapes × 2 slots run against the published registry and this one — 0 narrowed, 7 widened, 33 identical (test/spec_compliance/box_spacing_widening_probe.dart).

0.7.0 - 2026-08-05 — vector assets, and the ink that was painted under the page

SVG draws, in both the image and the icon slot, on every platform including the web. IconRef has named data:image/svg+xml as an ordinary form since 1.4 and icon's own example in the registry is assets/icons/heart.svg, so a runtime that could not draw them made the spec's shipped example false. Vectors take a picture widget rather than an ImageProvider, so the scheme dispatch lives in AssetResolver.vectorWidgetFor beside the raster one — §6.12 requires one resolution path for every AssetRef slot, and two dispatches would drift. All five forms resolve: data:, assets/, bundle://, client:// / origin (asynchronous, with the slot's loading state while the read is in flight), and network. Icons tint through a colour filter, which is what makes §2.5's "color applies to the SVG form" true rather than aspirational. Adds flutter_svg.

A tile reading SVG not supported was removed — it violated §6.12.4. That section forbids rendering the runtime's limitation in place of the asset, with Base64 not supported as its example; an undecodable payload takes the slot's declared fallback and the reason goes to the diagnostic channel. It was shipped for one round, verified as correct by a live check, and was wrong the whole time.

Ink is painted where the document can see it. ListTile.tileColor, selectedTileColor and the splash / focus / hover overlays are painted into the nearest Material, which is normally the app's — below every background the document paints on the way down. A page with its own background therefore covered them completely: the properties validated, rendered no error, and drew nothing. Both widgets now own a transparent Material, which is the fix Flutter's own assertion names. Measured live: 0 → 7,054 splash pixels with the page background in place.

Union-typed slots read every branch they declare. Dimension slots were read as as num? in 40 places, so the {value, unit} object and the binding form threw on sight; Action slots were cast to Map<String, dynamic>? in 120 places, so a list of actions rendered a cast error, and the common click slot accepted a list, rendered without complaint, and did nothing when tapped. Enum slots resolve their binding before matching. EdgeInsets accepts a binding, per entry as well as whole — {left: "{{sidebar.width}}", top: 8} is the shape documents actually write.

Properties the registry declared and the factory ignored, implemented: dataTable.filterable / resizableColumns / virtualScroll, tree.checkable / checkedKeys, textInput.showToggle / defaultCountry, numberField.showStepper, codeEditor.copyable, list.overscan.

Also in 0.7.0 — expressions the spec's own examples use

A validation block does something. The rules were parsed, validate was called on every keystroke, and the result was dropped — under a comment saying it would be used "later if needed". A field declaring required or minLength therefore accepted anything, which reads as input that was always valid. The message now shows on the field; an explicit error still wins.

§3.8 computed properties and §3.9 state watchers reach a document. Both were implemented and wired only to a runtime services.state block, so a page or application that declared them the way the spec writes them — inside its own state — got nothing at all: a computed value that never appeared and a watcher whose actions never ran, neither of which reports anything. They are read from the definition's state now, in the spec's own shape ("total": "{{a + b}}", dependencies detected from the expression) as well as the older {expression, dependencies} wrap.

debounce on a text field took the page down. The debounced field looked its own factory up as TextField while the registry key is textInput, so the lookup returned null and the ! threw during initState — every document that declared debounce, which is the property a search box exists to use, replaced its page with a null-check error. Both lookups use the canonical key now, and the window itself is pinned: held until it closes, only the last value in a burst delivered, and the caret never waits on it.

A bound selectedDate moves the calendar. The date was read once in initState, so a calendar bound to state kept showing the month it first rendered — a server push or a date picked elsewhere on the page changed nothing, with no sign that anything had been asked of it. Its day-select event also reports event.value now, alongside the event.date it already sent: every other input reports value, and that is what a document binds by habit.

channel.send on an inbound-only channel is reported. It logged one debug line and returned, so a document sending on an mcpStream got a success it could not tell apart from a delivered message.

A comma inside a quoted argument ended the argument. format(price, '#,##0.00') — §3.6.1's own example — arrived as three arguments, so the pattern lost its grouping and its decimals and 1234.5 came back as 1235. split(text, ',') had the same shape. The splitter respects quotes now, as it already respected parentheses.

A nested call was read as a variable name. An argument that was itself a call fell through to the path branch, so length(filter(items, 'completed')) — again the spec's example — looked up a variable literally named filter(items, 'completed'), found nothing, and answered 0 for every input.

min / max take the arguments they are documented with. §3.6.1 writes max(a, b, ...); the implementation handled exactly two, and a third made the whole call resolve to null — which a document shows as an empty value rather than as an error.

map accepts a lambda. filter and reduce both read one; map went straight to the property-name branch, stringified the lambda into a property no item carries, and returned every item unchanged — the input list, which reads as a mapping that did nothing rather than one that never ran.

{{runtime.version}} reports the version this package implements. It answered a hardcoded 1.1, two cuts stale and a number nothing else in the system used; it reads MCPUIDSLVersion.current now.

Client resources: a workspace or temp file could be written and then not read back. The containment check resolved the target through symlinks and compared it against an unresolved root, so any workspace reached through a link — /var/folders/… on macOS, and anything under it — rejected its own files as escaping. Both sides are resolved now. A custom resource provider that throws is reported as a result rather than escaping to the caller, and an unknown file extension is treated as binary, which is what its own application/octet-stream content type already said.

Channels: stopping a channel moves its state. The subscription was cancelled but _channelStates stayed on connected, so getChannelState and every binding reading it reported a live channel that would never deliver again — and toggleChannel, reading the same stale picture, refused to turn it back on. A channel action naming a channel that was never declared is reported (NOT_FOUND) instead of returning success, which left a page waiting for data with onError never firing.

Dialogs: showOverlay never worked — it looked for an Overlay above the overlay's own context and threw every time; it reads the navigator's overlay now. showInput disposed its controller while the dialog was still animating out, tripping a framework assertion in debug and leaving a listener on a dead object in release.

Batch: an empty actions list is a batch with nothing to do rather than an authoring error — a document that builds its actions from a filtered list produces one legitimately. A missing list is still an error.

Error boundary: the global FlutterError.onError and ErrorWidget.builder are restored when the boundary is disposed. Both were taken over and never given back — and ErrorWidget.builder was assigned from build, so the last boundary to build owned the application's error surface for the rest of the process, including after it was gone.

Also in 0.7.0 — a shell app can reach its own pages

A route declared in routes was unreachable inside a navigation shell. Four things had to line up and none of them did. The shell's MaterialApp was built with home: and no routes: table, so no named route resolved there. The shell registers a handler that maps a route to a tab index and returns false for anything else — its own comment says "let other handlers process this" — but the executor read that false as a refusal and stopped, so the fall-through to the navigator never ran. The tab strip itself was placed with DefaultTabController(initialIndex:), which only applies at creation, so a route-driven switch moved _currentIndex and the navigation state while the screen stayed where it was. And that controller's listener was attached inside build, stacking a new one on every rebuild.

Now: the document's routes are registered in both branches; a declining handler hands the route on instead of ending it; a programmatic index change drives the controller (a user tap still moves the controller first, and the shell follows it — pushing back in that direction fought the gesture); the listener attaches once.

A launch route is honoured wherever there is a shell. The shell picked its tab from appDefinition.initialRoute and never consulted RouteManager, so three stations opening the same application at /kiosk, /pos and /kds all drew the first tab (reported by konpi, 2026-08-03; present since 0.1.0). It reads RouteManager.initialRoute now, which is the requested route when the document declares it and the document's own otherwise. A launch route that names a declared page with no tab of its own — the usual shape of a scanned code — opens over the shell once the first frame exists, so back returns to the tab the document names.

ComputedManager: every computed property threw. _recompute hands BindingEngine a SimpleComputedContext, and the engine's resolution chain asks for themeManager before it knows whether the path is a theme path — the context was written to refuse, so nothing resolved. Watchers primed their baseline only when immediate: true, so the first change reported null as the old value and setting an unchanged value counted as a change. And dispose cleared its own maps while leaving its closures on the shared StateManager, so a discarded manager kept delivering for the life of the state object.

Also in 0.7.0 — one reading of Color

Four color parsers became one. The warning below was added to WidgetFactory.parseColor and then the axis was measured properly: three more parsers answered the same question differently, so whether a document was legal depended on which property it landed in. The page renderer took pink and transparent — neither is in §5.3.4 — knew no scheme slot at all, so a page backgroundColor: "primary" was silently dropped, and read #fff as 0xFF000FFF, a near-black blue, where the spec says white. The theme took rgb() and nothing else: no three-digit hex, none of the ten names. A dialog parsed #RRGGBB without an alpha channel, producing 0x00RRGGBB — fully transparent, for a background that had been asked for explicitly. All four now call DslColor.parse, which is §5.3.4 and nothing else: scheme slot, hex in three lengths, the ten basic names, and rgb()/rgba() (accepted here for the first time — the spec rated it SHOULD and the runtime rejected it).

Three holes in the warning itself. A malformed hex (#12345) returned null without a word, which is the failure the warning exists to stop. A valid scheme slot read on a surface with no theme was reported as not a color, sending an author to fix a correct line. And the warn-once set was an unbounded process-wide Set — colors arrive from state, so it grew for the life of the process; it is capped at 128 distinct values and says when it stops.

An unresolved binding reaching the parser stays silent: it is the binding layer's failure, and naming it a color error points at the wrong line.

Also in 0.7.0 — lazy implements what it declares, and an unknown colour says so

An unrecognised colour name is reported. parseColor returned null and the widget drew with no colour at all. Found on a live marketplace shelf: two bundles used color: "tomato" and went through publish, approval, purchase and install, then drew an uncoloured box on the buyer's screen with nothing anywhere to read. Color takes hex, the ten basic names and the Material 3 scheme slots — §5.3.4 says CSS keyword colours are not canonical — so the document is wrong, and the schema says so wherever a document is validated. An installed bundle is not, which is why the screen had to. Once per distinct value: a colour is read on every rebuild.

Found after 0.6.1 shipped, by fixing a harness rather than by a report.

lazy.content accepts the source form. §10.22 gives it two — an inline widget, and { source: "ui://..." } naming a fragment to fetch. Only the first was implemented: a source went to the renderer as-is, which answered Widget type is required, because a source is not a widget. Resolution is delegated to view rather than rebuilt — lazy decides when a subtree is built, view decides what a source resolves to — which also carries placeholder and onError through to surfaces that already implement them.

onLoad and onError fire. Both were read into locals and silenced with an unused_local_variable ignore, so a document that declared them waited for something that never came.

Prose §10.22 named the trigger values viewport / immediate / manual while the registry and the runtime have always used visible; a document written from the prose failed schema validation. The prose now matches.

Why it took this long to see. Every spec-compliance suite judged a frame after a single fixed 50 ms pump. lazy materializes from a post-frame callback, so its failure arrived after the assertion had already passed — the harness reported clean on a widget that drew an error box. The suites now settle (capped at one second, because an indeterminate progress indicator never settles and the default budget grinds for ten minutes before saying so). Re-run across all five axes, lazy was the only thing hiding there.

0.6.1 - 2026-08-03 — documents the schema accepts now draw

Every branch of every declared union now draws. A property typed number | binding was read as properties['x'] as String? in seven widgets: the cast throws the moment an author writes the number the schema plainly allows. resizable.width and .height, pdfViewer.page and .zoom, popover.open, stepper.currentStep, mediaQuery.condition, grid.columns and chart.data all took the page down on a document that validates.

Nothing caught it because nothing asked. The render matrix draws the examples the spec ships, and those examples happen to use the other branch — so the number form of resizable.width had never been rendered once. widget_union_branch_test closes that: 141 branches, one document per branch, built by overriding a single property on a document already known to draw.

Two-way properties wrote to the wrong place. The path was taken raw, so a document written the documented way — "width": "{{panel.width}}" — read through the resolver from panel.width and wrote back to a key literally named {{panel.width}}. The read worked, the drag persisted nowhere, and no frame ever looked wrong. twoWayPath unwraps the braces and rejects an expression, which has no single target to write to.

IconRef means all three of its forms, everywhere. The primitive says a name, a {codepoint} object and a {uri} object are accepted anywhere an icon is taken; seven slots accepted only the string, and two of those carried private icon tables that had drifted from the shared resolver. Fixing the crash surfaced two slots that were not drawing the author's icon at all — accordion.icon was read and never used, and link.icon drew Icons.link whatever the document said.

grid.columns accepts the responsive object the spec documents. It never did; the property was read as int?. The registry described that object with a {default, sm, md, lg} vocabulary that appears nowhere else in the spec — it now names the §14.1.1 form-factor labels the picker actually resolves, and pdfViewer's page and zoom are described as the one-way values they are, because an embedded viewer reports nothing back.

An out-of-range selectedIndex on bottomNavigation now clamps instead of tripping a framework assertion and taking the page with it.

A definition-level onInit can call a tool again. The hook runs inside initialize (§1.5.2 puts it before the first render) and the tool executor was registered from buildUI, so an application whose onInit loaded its first data reached nothing at all — no error to the author, and the server never saw the call. initialize now takes onToolCall too. A host that passes it only to buildUI keeps working and is told what happened: the "no executor registered at all" case is reported apart from "that tool is not registered", because the two send the reader to different places.

kanban joined §2.15. It grew per-column scrolling in this cut, which is what makes a widget need a bounded parent, and the hand-written list did not follow. bounded_parent_axis_test now pins that list against what actually happens under a scrolling page — including that the sizedBox remedy the section prescribes works.

A tab bar no longer rebuilds the page you came back to. Every branch of the application shell built its body from a FutureBuilder keyed on the current route, so switching destroyed the outgoing page and built the incoming one from nothing — onInit → onMount → onReady again, tools called again, images fetched and decoded again, on every tap. A page that loads its data in onInit, which is the shape §1.5.3 shows, re-fetched on every visit.

Pages now stay mounted: leaving one fires onPause, returning fires onResume, and it is the same instance in between. A page is built on its first visit, so six tabs do not run five onInits before anyone has opened them.

onPause / onResume had in fact never fired for a routed page at all. A page covered by a pushed route is not disposed either — dispose never runs and nothing else reports the change — so it heard nothing on the way out and nothing on the way back. Both paths now report: the pushed-over case through RouteAware's didPushNext / didPopNext, which is the framework's own answer to that question, and the shell case through the shell that owns the selection. A resume with no pause before it no longer fires — §1.5.2 draws them as a pair, and a page built already-selected was reporting onReady and then immediately onResume.

What a paused page contains is paused too. An instance-level lifecycle block heard onInit → onMount → onReady when its page opened and then nothing ever again — leaving the page paused the page, not the widget inside it, so a timer or a subscription started on mount kept running behind a tab nobody was looking at. Embedded view definitions follow the same way.

Each page hook is now dispatched under its own event name. All seven were labelled mount, so a host listening for pause would have heard nothing and one listening for mount would have heard every hook. Nothing registers such a listener today, which is why it was invisible.

A destroyed page no longer fires onPause. §6.8.3 said the unmount sequence opened with it; §1.5.1 defines the same hook as losing focus without being destroyed, and §1.5.2 draws it as half of (onPause ↔ onResume)*. The spec contradicted itself — its own back-navigation line resumed a page the line above had destroyed — and the runtime followed the wrong half. On a routed page that made onPause fire only on the way to destruction while onResume never fired at all, so a draft save or a timer stop written there appeared to run and was discarded with the instance. §6.8.3 now splits on the one question that decides it: does the outgoing instance survive?

§6.12.8 says what was previously nowhere: an asset carried as bytes through state gives up its identity, so it is re-sent and re-parsed on every delivery and the host never sees a reference it could apply a size policy to. §1.5.2 says the other thing that was nowhere: returning to a page is a new instance, not a resume, so a fetch in a page's onInit runs on every visit.

Two deprecation warnings were pointed at the wrong people.

The legacy tools.<tool>.result mirror warned where it is written — on every successful tool call. An author using auto-merge, which is the recommended path and the common one, was told about a deprecation they cannot act on; an author who actually reads that namespace heard nothing, because reading a value that is present succeeds quietly. When the mirror goes, the second author is the one whose document stops resolving. The warning now fires at the read, once per path. The mirror itself still writes: removing it today would break those readers silently, which is the failure the warning exists to prevent. Its "removal in 0.6.0" line is gone too — this release is 0.6.1 and the mirror is still here, so the sentence had stopped being true.

A theme that declares a role Material 3 retired (background, onBackground) now says so rather than quietly resolving to the replacement.

Chart padding scales with the box. Every paint method opened with a flat 40px gutter and returned early when it left no room. A 140-tall chart with a legend has 77px for the plot, so it drew a panel and nothing inside it — no exception, no error widget, no warning. Turning the legend on by default made that the common case; the flat number is what made it silent.

data: images are decoded once per URI. MemoryImage keys on the byte list's identity, so decoding the same URI again produced a provider Flutter's image cache had never seen: every rebuild re-ran the base64 decode and the image decode for a picture that had not changed. Bounded at 64 entries, oldest-first — a document can name any number of data URIs, and holding all of them trades a stutter for a leak.

label is declared on the eleven input widgets whose factories already read it. otpInput and rating are left alone: theirs do not.

Three properties were declared, validated, and never drawn. A new suite asks what a widget shows rather than whether it drew — the render matrix cannot tell a working widget from one that ignores half its document, because both produce a clean frame.

• chart read only showLegend, a name that appears nowhere in §10, and defaulted it to false. A chart written the documented way — with options.legend.position — declared its dataset labels and drew no legend at all. The position is now read and honoured (none hides it); the legacy flag is consulted only when the documented property is absent, so a stale key cannot override the spec'd one.
• scrollView read child and ignored children and slivers, both of which the registry declares. Its own example scrolled an empty viewport. Slivers are laid out in order rather than dropped: this scroll view cannot host the sliver protocol, and content in the wrong arrangement beats content that vanishes.
• floatingActionButton required an undeclared isExtended flag before it would draw its label — which §2.8.7 documents as "Extended FAB label", with no such flag anywhere. Supplying a label now asks for the extended form; isExtended still wins when set explicitly.

Theme roles resolve the same from both positions. {{theme.color.<role>}} went through a path that only knew what the bundle had declared, while color: "<role>" derived the rest from seed — so a seed-only theme answered one way in a colour property and returned empty to a binding. §5.3.1 says the missing roles derive; that is now true from either.

MCPLogger.onRecord lets a host receive the runtime's diagnostics. Without it they reach dart:developer and nobody else, which is the wrong audience for a message aimed at whoever wrote the document — a theme role declared and dropped, for instance. Records reach an installed sink in every build mode; enableLogging still governs only the developer-log path. Declaring a role Material 3 retired (background, onBackground) now says so instead of quietly resolving to its replacement.

registerWidget may now be called before initialize, and validation honours what it registers. It used to throw before initialization, which made host widgets impossible to use as documented: schema validation runs inside initialize, so a type registered afterwards was rejected in the very document that introduced it, and the host was told its own extension was malformed. Offering an extension mechanism and refusing what it produces is a contract disagreeing with itself. The extension's own subtree is the host's contract and is not checked; everything around it still is, so an unregistered type stays the error it should be. registerAction is unchanged.

StateChangeEvent is exported alongside StateManager — a host bridging two runtimes has to name the type it receives from StateManager.stream.

Widgets are now drawn before release, not only validated. test/spec_compliance/widget_render_matrix_test.dart renders every widget in the registry — each example the spec ships for it, plus a document synthesized from its required properties — and fails on a drawn error widget as well as on a thrown exception, since the renderer reports a broken widget by painting a red box rather than by throwing. The first run failed 29 of 158. Everything below is what that found; none of it was new breakage, and none of it was reachable by schema validation, unit tests or a build, all of which were green.

• resolve<T>(null) threw whenever T was non-nullable. Factories were written as resolve<String>(properties['x']) as String? ?? '' — the author expecting null and supplying a fallback — and the cast threw before the fallback could run, so every one of those fallbacks was dead code. That is why markdown never once resolved the content alias its own source comment says it accepts, and why any binding that had not been set yet crashed the widget rather than falling back. Fixed at 26 call sites.
• JSON integers were cast straight to double. "width": 640 threw in 19 places across 8 widgets. They now go through parseDimension, which takes both the number and the {value, unit} object the schema allows.
• dataTable read sortColumn / sortAscending without resolving them, though the spec declares both binding — the documented form threw. Both were also read and discarded behind ignore: unused_local_variable, so the documented sort did nothing at all. It now dispatches onSort from sortable headers with event.column and applies the sort to the rendered rows.
• staggeredGrid cast columns to a number, though §declares number | object and its own example passes the responsive { default, md, lg } map; scrollDirection was read and discarded, so horizontal looked like it had taken. Both honored.
• stepper required each step's title to be a widget while §2.6.20's example writes a string, falling back to a titleText key that appears nowhere in the spec.
• splitter read sizes as a string only, so the literal array in its own example threw. segmentedControl asserted when its bound selection had no value yet — the normal state of a fresh document. dragTarget rejected the children form the registry documents. webView called setState from initState, so any platform without a web view failed the whole page instead of reporting through onError.

dateTimePicker.dateFormat / timeFormat and pdfViewer.showZoom were declared in the spec and never read by their factories, so setting them did nothing. Found by the drift audit once its prose parser learned to read table rows that name two properties in one cell.

dateFormat / timeFormat substitute the common pattern tokens (yyyy, MM, dd, HH, hh, mm, ss, a); the bound value stays ISO-8601 regardless, so this changes only what the closed field shows. showZoom: false pins the view, since the PDF open-parameter set has no control for hiding the zoom widget on its own.

Picks up flutter_mcp_ui_core 0.5.1, whose schema stops silently accepting malformed children. The floor stays ^0.5.0 — this is the same 1.4 cut, finished, not a second one. Two documents in this package's own suite were relying on the gap: the demo_ui timeline fixture bound its entries to events, which the factory does not read (that panel had been rendering empty), and a form-flow document carried marginTop / marginBottom inside style, which nothing reads.

0.6.0 - 2026-08-03 — One asset path, 23 widgets, openUrl (spec 1.4)

Changed — documentation

• README states 1.4 rather than 1.3, and its Quick Start compiles. It showed an MCPUIRenderer widget that has never existed in this package, with no Flutter import. Rewritten around MCPUIRuntime.initialize + buildUI(), including the point that buildUI() supplies its own MaterialApp when the definition declares navigation — wrapping it in another is what made every test in the showcase example see two Scaffolds.

Fixed — the report that started this

A server read its own bundle, resolved the assets to data: URIs and put them in state, and neither widget that can paint an image could show them. image rendered the words "Base64 not supported" where the picture belonged. box.decoration.image was the only field in its own resolver that never went through context.resolve, so a bound source arrived as the literal "{{item.picture}}" and matched no scheme.

Both were symptoms of one absence: every factory hand-rolled its own startsWith chain, and between all of them only http(s), assets/ and data: were ever handled — exactly the three a synchronous loader can build. bundle:// and client:// were declared by the spec and implemented nowhere.

• lib/src/assets/ — AssetRef parsing, AssetResolver with injected readers for bundle / client / origin sources, and AssetRefImage so the asynchronous forms wait inside an ImageProvider and widgets stay synchronous (spec §6.12.5).
• supportedForms is honest by construction: a form appears only when the reader serving it was injected, so a runtime cannot declare more than the host wired (§6.12.4, §18.2.12).
• image / avatar / icon / box.decoration converge on that one path. avatar and icon consequently accept data:, bundle://, client:// and the object form, where they used to accept two schemes and one.
• No dart:io: client:// is an injected port, so the runtime still builds for web and each host supplies the reader its platform can honour.

Changed — narrowing (why this is a minor)

• An empty string is no longer a valid asset source. A source that may be absent is expressed as a binding; the runtime treats a binding resolving to empty as unresolved (§6.12.2a, §6.12.4).
• segmentedControl renders its three variants differently. All three resolved to SegmentedButton, so a document declaring tabs or buttons got the same control and its declaration meant nothing.

Added — 23 widgets

Core fileInput multiSelect combobox otpInput dateTimePicker accordion popover menu contextMenu breadcrumb pagination link Advanced qrCode barcode pdfViewer diffViewer richTextEditor splitter resizable kanban gantt spreadsheet Client voiceInput

Each carries the part its composition drops. otpInput distributes a pasted or autofilled code across cells and declares one-time-code intent through a single field — a row of textInputs has neither. combobox owns focus: the list never takes it, arrows move a highlight without moving the caret, Escape closes without clearing. accordion keeps collapsed panels in the tree, since a removed subtree reads to assistive technology as content that does not exist. kanban's drop targets are the gaps between cards, so a move reports where it landed. gantt lays header and rows from one scale, which is what a grid-based composition cannot keep aligned through scroll. spreadsheet evaluates formulas through the binding engine — the §7.1 sandbox — or not at all, and formulas is off by default.

qrCode and barcode carry pure-Dart encoders rather than a dependency: this runtime is embedded in several hosts, so a rendering dependency here is one all of them take on every platform. Both refuse rather than emit something wrong — a payload past capacity, contrast below 3:1, an EAN-13 whose check digit does not match.

pdfViewer and voiceInput split by conditional import. The web branch works for real (the browser's own PDF support; SpeechRecognition); the branch that cannot reports through onError rather than rendering a control that does nothing.

Added — navigation.openUrl (spec §4.3.3)

Core had no way out of the application. Opening is the host's act, so the runtime enforces the §7.3.4 scheme policy — javascript:, data:, file:, blob:, vbscript: refused before the host is asked — and delegates through a callback, the shape openApp and exitApp already use. Every refusal reports: no handler, a host that declines, and a host that throws all fail loudly, because a silent no-op is indistinguishable from a broken document.

Added — 17 palette aliases

dataGrid treeView meter video audio modal dialog alert confirmDialog toast skeleton tag steps scrollArea numberInput dropdownMenu code label, plus autocomplete collapsible hoverCard navLink on the new widgets. Accepted on input, never emitted.

Fixed — an intermittent lifecycle test, and the code under it

ResourceEntry.updateState compared age with a strict >, so Duration.zero — which means "already stale/expired on load" — only took effect if the clock had ticked between markReady and the call. The same assertion passed or failed by scheduling, and the suite failed intermittently on a different case each run. Now inclusive; non-zero durations are unaffected, since age crosses those between ticks either way.

Dependencies

• flutter_mcp_ui_core ^0.4.3 → ^0.5.0, mcp_bundle ^0.4.8 → ^0.4.9
• adds web — reached only through conditional imports, never compiled into native builds. isA<JSFunction> was avoided so the SDK floor stays at 3.0.

0.5.4 - 2026-07-31

Fixed — registerAction could not be called from outside the package

MCPUIRuntime.registerAction(String type, ActionExecutor executor) is public, but neither ActionExecutor — the type it asks for — nor ActionResult — the type that must be returned — was exported from the library. A host had no way to name either, so the method was unreachable and custom action executors could not be supplied at all.

Both are now exported. Additive: no existing name moved or changed. A regression compiles a host-defined executor against the library barrel, which is the only thing that can catch this — every in-package test names the types through their source files and passes regardless.

Fixed — a definition's own initial state discarded entry.* and identity.* (§8.9)

A host adopts the entry and identity, then the definition's initial state is installed as a wholesale replacement of the state container — which cleared the roots they had just been published into. Every entry.* / identity.* binding then resolved to null for any definition declaring state.initial.

The symptom is silence rather than an error. A deep-linked screen renders with blanks where the link's parameters belong and reads as an ordinary visit by someone who is not signed in, which is precisely the reading §8.9.6 reserves for a runtime that does not implement this section at all.

Both definition types were affected through different calls — an application replaces the container, a page initializes it — and every sample document is a page. Routing was never affected: a launch route is read from the session rather than from state, so the deep link landed on the right screen and only its parameters went missing. identity.* recovered on the next promotion, since that writes a single path; entry.* never returned, because nothing re-adopts it.

StateManager now takes reservations: reserveHostRoot(root) marks a root as held on behalf of someone other than the document, and both setState and initialize carry reserved roots across a replacement. EntrySession reserves entry and identity when it is constructed. A reserved key present in the incoming state does not win — §8.9.2 makes these read-only to the document, so a collision is shadowing rather than supplying.

The reservation is registered rather than named inside StateManager, so a container that holds no host facts — an embedded scope's own state tree (§6.11.3) — reserves nothing, and a document there may keep its own state under those names.

Why it shipped: the §8.9 suite booted definitions with no state.initial, which is the one shape that hides this, and the launch-route assertions read the session object rather than a binding. Both gaps are closed: the regressions now cover application and page, and assert through resolved bindings.

0.5.3 - 2026-07-28 — Composition Profile: rendering definitions from other origins (spec 1.4)

Implements the consumer side of composition. Spec 1.3 §11.9 dashboard already said how an application presents itself when embedded — nothing said how an application embeds. This release adds that, so one bundle can compose several MCP servers into one product.

Fixed — lifecycle hooks (spec §1.5, §6.8, §9.9.1, §18)

Auditing the seven hooks of §1.5.1 against this runtime found that no mount path implemented the full set, and that hooks were being dropped before execution ever came into it. A page written exactly the way §6.8.1 shows it — subscribe in onReady, release in onDestroy — parsed as a page with no hooks at all, so a device's live reading streamed when the page was embedded and sat blank when the same page was opened on its own, with every layer beneath reporting success.

Parsing. LifecycleDefinition.fromDefinition(definition) replaces fromJson(lifecycleObject):

• Reads both placements §1.5.3 allows — top-level hook fields on the definition and a grouped lifecycle object — and merges them. Only the grouped form was read before.
• Accepts a single Action as well as an array (§1.5.1). A bare Action returned null, which is a hook that never runs.
• The canonical name is onInit (§1.5.1). onInitialize is accepted as a deprecated alias.
• onEnter / onLeave are not spec hooks — §6.8.3 already routes a page through onMount / onUnmount — so they are folded onto those as deprecated aliases.
• A hook named in both placements is an error per §1.5.3; until 0.6.0 it warns (LifecycleDefinition.aliasWarnings) and keeps one copy, so a document that used to load still loads. fromJson remains as a deprecated shim. Both removals land in 0.6.0 alongside the deprecations already announced for that release.

Execution. New LifecycleRunner owns hook order for every mount site; a site now says only when it mounted:

• Routed pages run onInit / onReady / onDestroy, which they never did — they ran only onEnter / onMount / onLeave / onUnmount, two of which are not spec hooks.
• Applications run onMount / onUnmount, and take onPause / onResume from the parsed definition rather than only from a legacy runtime-config path that a document could not reach.
• Embedded views release on unmount. The embedded path started subscriptions and never ended them, so a tile that went away left the node streaming to a scope nobody read.
• Teardown has one owner — the widget that mounted the definition. Navigation used to tear the outgoing page down as well; with onLeave folded onto onUnmount that overlap would have fired the same hook up to three times and onDestroy twice.

Placements that were never implemented at all:

• Instance-level hooks on any widget (§6.8.2) — a widget's own lifecycle: {} block was read nowhere, so it was silently dropped. New LifecycleHost wraps a widget only when it declares hooks.
• Template instances (§9.9.1, and a MUST in §18) — a template's onMount / onUnmount fire once per instance. UseTemplateFactory ran neither.

Covered by test/runtime/lifecycle_matrix_test.dart: the same document mounted as a routed page, as an embedded view, and as an instance-level block must run the same hooks in the same order. Each path passed its own tests in isolation before, which is why the divergence stayed invisible.

Added — entry & identity (spec 1.4 §8.9)

A definition is often reached from outside the app — a scanned code, a tag, a link — and the viewer may or may not be signed in. This adds the consumer side of that: what a document may read about its arrival, and the one transition it may request.

• entry.* / identity.* bindings — entry.route, entry.params.*, entry.issuer.*, entry.grant.scope, entry.canSteward, entry.notice, identity.state, identity.subject.*, identity.canPromote. Read-only, and null on a runtime whose host wired nothing (§8.9.6), so a document written against §8.9 degrades to its guest rendering instead of failing.
• identity.promote / identity.release actions — carry no credential in either direction; the result reports only whether the transition occurred. Unsupported (not failed) when the host wired no handler.
• The value types (EntryContext / IdentityContext and friends) live in flutter_mcp_ui_core alongside the other spec types; this package re-exports them and owns the behaviour. A type that only a Flutter runtime can name is a type an authoring tool or validator cannot check.
• EntrySession on the runtime — the host adopts an entry, adopts or replaces the principal, and registers promotion handlers. Replacing the principal re-evaluates bound expressions in place: the document is not rebuilt and its state is not discarded (§8.9.4).
• Launch route — MCPUIRuntime.initialize(..., launchRoute:) opens the definition at a requested page instead of its own initialRoute, and entry: implies one when the entry named a route. The two are kept apart deliberately: §8.9.1 reserves the entry.* tree for definitions reached from outside, so an in-app navigation.openApp sets only the route. Folding it into an entry would make every app-to-app open read as a scan to a document asking how it was reached. A route the document no longer declares is not honoured silently: the runtime falls back and reports RouteManager.launchRouteMissing, because a stale binding that renders the home page looks exactly like a working one.

entry.params is a separate root from route.params by design — route parameters say where in the document the viewer is, entry parameters say what was scanned to get here, and only the latter survives internal navigation.

These bindings are not authority. They decide what a screen offers; every privileged operation is still authorized at the serving origin (§8.9.5).

Two guards found by mutating the harness rather than by review:

• A state action targeting entry.* / identity.* is rejected (READ_ONLY_BINDING) instead of silently dropped.
• Resolution has a dedicated branch ahead of the generic fallback. Without it the fallback searches page and app state first, so a document could set its own page.entry and forge both canSteward and a launch route. Pinned by test/entry/entry_identity_test.dart "document state cannot shadow entry.* or identity.*" — the first version of that suite passed with the branch removed, which is what surfaced the hole.

Added

• view widget (src/widgets/utility/view_factory.dart, spec §2.13.1) — embeds a DefinitionSource anywhere in a tree. Accepts all four source forms (§1.9.1): an inline definition, a ui:// uri on the current origin, a qualified { $ref, from } reference to another origin, or a binding to a definition held in state. Supports props / fallback / loading / onError / theme.
• MCPUIRuntime.registerDefinitionResolver(resolve) — the host seam, mirroring registerStreamSource. The runtime never learns how a connection is opened; establishing outbound connections is a host capability (§6.11.1). Held on Renderer (root contexts are created on demand) and carried down by RenderContext.createChildContext.
• RenderContext.createEmbeddedScope({props, inheritTheme}) — the isolated scope an embedded definition renders in (§6.11.3, §7.10.1). A fresh StateManager is what makes the isolation real; props is the only embedder→embedded channel, and localVariables are deliberately not inherited.
• RouteValue widened to any DefinitionSource (src/routing/route_value.dart, spec §1.2.1) — a whole route may be another origin's page. Origin-carrying route values normalise to a page whose content is a single view, so the route surface and the widget surface cannot drift apart; both go through one implementation. Inline PageDefinition route values (a v1.0 spec form this runtime had never supported) now work too, as does the v1.3 {page, transition} wrapper.

Changed

• RouteInfo.pageUri typed String → dynamic. A route value is no longer necessarily a uri. Source-compatible (Dart implicitly downcasts from dynamic), and a uri route still yields a String; only the new structural forms differ. No consumer outside this package's own tests reads it.
• Page caching keys through routeValueCacheKey() in both consumers (RouteManager, ApplicationShell). Structural routes key by route path, not by uri — two routes reading the same uri from different origins must not share a cache entry, which would render one device's UI on the other's route. The same key is used by the lifecycle lookups so onEnter / onLeave / pagePause keep firing for composed routes.
• flutter_mcp_ui_core floor raised ^0.4.2 → ^0.4.3 (the regenerated widgets schema carrying view). Consumers should bump to ^0.5.3.

Security

• Registering a resolver is how a host claims the Composition Profile. Without one, view fails closed and renders its fallback — it does not resolve a foreign $ref against the host's own origin, which would put one server's UI under another's identity (spec §7.10.1 rule 6, §18.7.3).
• An embedded scope cannot read the embedder's state, and failure is contained per view: a dead origin renders that view's fallback while its siblings and the embedding page keep rendering.

Fixed — analyser cleanup shipped in the same cut (62 issues → 0)

Not cosmetic-only; three of these change behaviour and are called out as such.

• BuildContext used across await (6 sites) — PermissionManager._promptUser / checkAndPrompt and ClientActionHandler could raise a dialog on an element that had already been unmounted (a page popped while the action was in flight), which throws. All six now re-check context.mounted first; a gone surface yields "no decision" instead of an exception. One pre-existing // ignore: use_build_context_synchronously was replaced by a real guard. Behaviour change: a permission prompt whose surface disappeared mid-flight is now declined rather than throwing.
• Radio / RadioListTile migrated to a RadioGroup ancestor — Flutter deprecated the per-widget groupValue/onChanged pair. radioGroup now wraps its tiles in one RadioGroup; the standalone radio widget carries its own single-item group so DSL documents are unchanged. Behaviour change: the widget tree gains a RadioGroup node, which downstream widget tests that assert on tree shape may see.
• SemanticsService.announce → sendAnnouncement — the replacement requires a FlutterView, and these call sites are manager classes with no BuildContext, so they now resolve the same implicit view the deprecated call used internally. Behaviour change: with no implicit view (multi-window / view-less embedder) an announcement is skipped rather than asserted.
• cacheExtent → ScrollCacheExtent.pixels(...) in listview_factory / virtualized_list (typed replacement; same pixel value, DSL key unchanged).
• Matrix4.scale / translate → scaleByDouble / translateByDouble.
• Deferred-renderer placeholders in phase_2_4_factories no longer bind unused locals (the property reads that record author intent remain).
• Legacy-form bundle adapters (bundle_page_adapter, bundle_ui_adapter, ui_definition) read deprecated inline fields on purpose — that is what makes older bundles keep working. Those reads now carry a single-line // ignore: with the reason stated, instead of appearing as unresolved debt.
• Assorted lints: curly_braces_in_flow_control_structures, prefer_const_constructors, unnecessary_brace_in_string_interps, no_leading_underscores_for_local_identifiers, a nullable TabController that is non-nullable.

dart analyze lib is now No issues found, and the publish dry-run no longer reports an analyser warning.

Notes

• Purely additive for existing documents: from absent means the current origin, so every 1.3 document keeps its exact meaning.
• Tests: 21 new (test/widgets/v14/ — view 10, RouteValue 11). 4341/4341 green (full suite, re-run after the cleanup above).

0.5.2 - 2026-07-19 — client.mcpStream channel type: MCP-server-pushed live streams (spec 1.3 §8.6.2)

Added

• client.mcpStream channel type — the first channel that carries an MCP-server-pushed live stream. The prior five types cannot: client.poll re-invokes a tool on an interval (pull) and client.websocket is a raw socket outside MCP. client.mcpStream subscribes a host-registered stream source identified by its uri scheme and forwards each server push through the normal channel machinery (lifecycle, backpressure, onMessage/onError/onConnect/onDisconnect). McpStreamChannel (src/channels/channel_types/mcp_stream_channel.dart) implements it; ChannelManager._createChannel gains the case with a late-bound resolver (the channel is created at page init but the host registers its source after runtime init, so resolution is deferred to start()).
• MCPUIRuntime.registerStreamSource(scheme, open) — the host seam. A host wires a real transport per uri scheme (e.g. ble → a BLE scan hub) while the runtime stays transport-agnostic; all schemes share one resolver on the channel manager. Mirrors registerToolExecutor.

Changed

• flutter_mcp_ui_core floor raised ^0.4.1 → ^0.4.2 (the regenerated page schema listing client.mcpStream); mcp_bundle floor raised ^0.4.0 → ^0.4.8 (floors-at-latest on cut). Consumers should bump to ^0.5.2.

Notes

• Purely additive and version-neutral: a runtime predating the type hits _createChannel's default branch and ignores the unknown type (graceful coexistence). The major.minor DSL-version gate (MCPUIDSLVersion) is unchanged — since v1.3.

0.5.1 - 2026-05-23 — spec compliance Round 2 + mcp_bundle 0.4.0 cascade

Changed (cascade)

• mcp_bundle caret bumped from ^0.3.0 to ^0.4.0. The downstream UiSection.pages field switched to Map<String, PageDefinition>; this runtime's bundle/bundle_page_adapter.dart now iterates uiSection.pages.values so bundle activation still walks every page. Consumers should bump to ^0.5.1.
• flutter_mcp_ui_core caret bumped to ^0.4.1 (mcp_bundle cascade).

Added

• MCP wire shape unwrap — tool responses shaped as {content:[{type:'text', text:S}], isError:bool} now unwrap and JSON parse S before auto-merge (spec §3.10).
• StateChangeEvent.source canonical enum (action / tool / subscription / system) per spec §3.11. mergeState defaults to 'tool', StateActionExecutor to 'action', resource notification to 'subscription', updateAll to 'system'.
• RenderContext.onResourceRead / onResourceList — separate host callbacks for spec §4.5 read / list sub-actions (fallback to onResourceSubscribe for backward compat).
• onSubscriptionError callback — spec §4.5 named field, dispatched when host subscribe handler throws. event.{uri, binding, message} child context.
• Non-Map response event.value wrap — spec §4.4.2: list / scalar / null tool responses expose event.value = <response> (with other event.* keys null).
• Common click field auto-wrap (spec 1.3.4 §2.2) — WidgetFactory.applyCommonWrappers now wraps any widget carrying a click: Action property in a GestureDetector and dispatches the action through RenderContext.actionHandler on tap. Universal across all 97 factories that call applyCommonWrappers; pure layout / decoration widgets (box, card, linear, stack, ...) become tappable without nesting a gestureDetector wrapper. click is resolved through the binding engine, so action maps may be supplied inline or via {{...}} binding. Click is applied BEFORE the enabled-state wrap so enabled: false (IgnorePointer) correctly suppresses the gesture surface. Widget-local activation slots (button.onTap, iconButton.onTap, richText.spans[].onTap, ...) remain canonical for those widgets and are unaffected.
• 26 new regression cases under test/spec_compliance/runtime_spec_fix_2026_05_14_test.dart locking the above.
• 6 new regression cases under test/renderer/widget_factory_test.dart for the common click field: GestureDetector wrap shape, end-to-end tap → action dispatch, tooltip + click coexistence, backward-compat no-click pass-through, non-Map click ignore, and enabled:false suppression via IgnorePointer.

Deprecated

• Envelope {success, result, message} auto-unwrap — slated for removal in 0.6.0. Warning logged once per process.
• tools.<tool>.result namespaced mirror — slated for removal in 0.6.0. Warning logged once per process.

Changed

• runtime_engine.handleResourceNotification / handleMCPNotification no longer apply content[binding] heuristic — raw content stored at binding per spec §4.5.
• Lifecycle _renderContext null short-circuit replaced with explicit error log.

Fixed

• Storage, one-shot reads and permissions did not scope to the origin either. A resource read from an embedded subtree returned the embedder's resource under the embedded document's uri (a wrong answer, not a missing one); two devices on one screen shared a single storage key space, so the second to write a key silently overwrote the first and each read the other's value back as its own; and an embedded document could prompt for — and be granted — a permission the embedding app never held, which let any embedded server escalate through the screen it was given. Reads now route through registerOriginResourceReader, storage keys are prefixed by the scope's origin, and a scoped action is refused before any prompt when the embedder does not hold the permission.
• An embedded subtree rendered against its origin but did not act against it. view brought another origin's UI in; every tool action inside it still took the app's own path and landed on a session with no client for that device, so a composed screen looked finished and did nothing (observed as session.tool.no_client while both tiles rendered). RenderContext now carries an ambient origin — set on the embedded scope, inherited by every descendant, never read from the renderer because an origin scopes a subtree rather than a tree — and a scoped tool action routes through the host's registerOriginToolCaller. A scoped subtree with no bridge reports rather than redirecting: running one device's tool name against another server is worse than failing.
• The resolver did not reach the context a page renders with. registerDefinitionResolver stores it on the Renderer, and each RenderContext copied the field at construction — but two of the five construction sites did not, including the router's, which is the path a bundle takes. A host that had claimed the Composition Profile therefore saw view report that the runtime does not implement it. RenderContext now reads through to its renderer, so the profile reaches the tree by construction rather than by every construction site remembering; an explicitly-set resolver still wins.
• ApplicationDefinition.fromUIDefinition narrowed routes to Map<String, String>, so an application carrying a v1.4 route that names another origin ({"$ref": ..., "from": {"connection": ...}}) threw while parsing and the app could not open at all. The error named a type cast, not routes, so nothing pointed at composition. Routes now keep their declared shape.
• Tool responses arriving in MCP wire shape were merged as content / isError literal keys instead of unwrapped — now spec §3.10 compliant.
• TemplateParamDefinition.validate now skips declared-type and enum checks when the supplied argument is a binding expression ("{{...}}"). Mirrors the same fix in flutter_mcp_ui_core's TemplateDefinition.validate; covers the extended-template (resolveExtended) path. Previously a template param declared type: boolean rejected every expression-bound argument (always a String at validate time), causing use invocations to surface the Template not found: placeholder. Spec §9.3.1 mandates only required / default / enum / validator and expressions resolve at runtime so cannot be compared against the enum list here either. Non-expression arguments still take the type / enum path unchanged. Regression: full templates test suite 88/88.
• TemplateRegistry._substituteValue now type-preserves whole-value placeholders. A param value shaped as a single "{{name}}" (with no surrounding literal text) was previously stringified by _substituteString via value?.toString() — a List param landed in the expanded template body as "[a, b]", a Map as "{x: 1}", an action Map ({type:"tool",...}) as "{type: tool, ...}". Downstream factories receiving those props could no longer cast back to List / Map<String, dynamic>? (observed runtime: 'String' is not a subtype of type 'Map<String, dynamic>?' from inkWell.onTap when a template params.onActivate action Map was forwarded into a nested use). The substitution now short-circuits whole-value placeholders to the raw param value; partial placeholders ("Hello {{name}}") still take the string path unchanged.
• ListViewWidgetFactory._ensureStableConstraints is now orientation-aware. The defensive guard that wraps the ListView in a SizedBox when the parent supplies an unbounded constraint previously only checked hasBoundedHeight, so a list with orientation: 'horizontal' mounted inside a Row with a Spacer / Expanded sibling threw Horizontal viewport was given unbounded width at layout time (followed by a cascade of RenderBox was not laid out exceptions). The guard now branches on scrollDirection: horizontal lists check hasBoundedWidth and fall back to SizedBox(width: MediaQuery.size.width); vertical lists keep the existing hasBoundedHeight / SizedBox(height: ...) path. Author intent is unchanged — explicit shrinkWrap: true or a parent-supplied size still short-circuits the guard.
• text widget pins theme.color.onSurface when style.color is unspecified. Spec §5.4.2 deliberately omits a color field on typography roles (Material 3 separates typography from colour), so variant-only / no-style.color text returned TextStyle(color: null) and Flutter fell through to the ambient DefaultTextStyle.of(context).color — which inherits from an ancestor Theme whose brightness can briefly diverge from the ThemeManager's effective mode during host tab transitions (an AppRendererScreen remount sees a stale MediaQuery / Theme(brightness:) frame before the host wrap re-applies its override). Visible in dark mode only — both ambient branches yield near-black under light, so the divergence is invisible there; in dark the same race surfaced as black-on-dark text frames after tab cycling. The factory now resolves theme.color.onSurface (the M3 canonical text colour) through ThemeManager at build time, breaking the ambient dependency. Author-supplied style.color still wins via the existing merge path. Regression: 2 new widget cases in test/runtime/text_color_pin_test.dart (onSurface pinned despite light-Theme ancestor / inline style.color overrides the pin).
• ThemeManager.flutterThemeMode now honours _hostBrightnessOverride unconditionally (in lockstep with _resolveEffectiveMode). Previously the override only applied when the bundle declared mode: 'system', so a bundle with mode: 'dark' would resolve theme.color.onSurface to the host-pinned brightness via getColorValue while MaterialApp.themeMode still picked dark — the colour-token path and the ambient ColorScheme came from different brightnesses, producing the "ambient onSurface flips between frames" race the tab-cycle text fix above is the second half of. Regression: 5 new cases in test/runtime/text_color_pin_test.dart::flutterThemeMode honours host override unconditionally. Test theme/theme_manager_test.dart::TC-TH-03 flutterThemeMode ignores host brightness ... was inverted to lock the new contract (renamed to ... honours host brightness ...) — policy change 2026-05-21, AppPlayer-class hosts are themselves "the system" for embedded bundles.
• ThemeManager._resolveEffectiveMode now treats a non-null _hostBrightnessOverride as the unconditional winner — previously the override only applied when _themeMode == 'system', so a bundle that hard-declared theme.mode: 'dark' ignored the host's light/dark toggle entirely. Worse, the toggle's apparent effect depended on race-timing between setTheme(appDef.theme) (driven by the bundle's manifest at mount) and setHostBrightness(...) (driven by the host's chrome preview-mode pin) — whichever landed last won, producing an intermittent "text widget stays dark / surrounding chrome flips light" leak in tools/builder/vibe_studio/vibe_studio_workspace. setHostBrightness also now notifies unconditionally (the previous if (_themeMode == 'system') notifyListeners() guard would swallow the brightness change when a bundle declared an explicit mode). AppPlayer-class hosts are themselves "the system" for embedded bundles — when the host pins brightness, the bundle MUST follow. The identical-override early-return guard (_hostBrightnessOverride == brightness) is preserved, so no spurious rebuild. Regression: 6 new cases in test/runtime/theme_host_override_priority_test.dart (light flips dark bundle / dark flips light bundle / clear restores declared / always-notify / identical no-op / fingerprint changes for renderer cache invalidation).
• RuntimeEngine.initialize now forwards ThemeManager mutations to engine listeners. setTheme / setThemeDefinition / setThemeMode / setHostBrightness / applyOverride calls already invoked ThemeManager.notifyListeners() (six call sites), but the engine never addListenered on _themeManager, so the notification stopped at the manager and widgets never rebuilt on a theme mutation. Hosts worked around this by bridging through _stateManager as a noop forward (sentinel: tools/builder/vibe_studio/.../dsl_workspace_view.dart). Spec mcp_ui_dsl/spec/1.3/05_Theme.md §L56 ("theme.mode … changes trigger theme recomputation and re-render") makes this re-render obligatory; the engine now satisfies it natively. The listener tear-off (_themeListener = notifyListeners) is held on the engine and detached in destroy() — ThemeManager is process-singleton, so an unreleased listener would outlive a destroyed engine and fire notifyListeners on a disposed receiver. Multi-host theme isolation (per-runtime ThemeManager) is unrelated to this fix and remains a separate refactor track. Regression: 3 new cases in test/runtime/theme_forward_test.dart (theme mutation forwards / destroy detaches cleanly / host bridge workaround is no longer necessary).

0.5.0 - 2026-05-03 - Spec ↔ implementation alignment (1.3.3)

• Channel callbacks: onMessage (canonical, onData retained as getter alias) + new onConnect / onDisconnect dispatch.
• chart adds donut / polar / bubble; codeEditor accepts 7 themes (vsLight/vsDark/monokai/solarizedLight/solarizedDark/github/dracula) + 14 languages.
• lazy.trigger: visible (spec rename from viewport); manual case recognised.
• services.kind: polling / subscription accepted (mapped to existing periodic / continuous).
• template.styles map field; bottomBar / rail navigation canonical (legacy bottomNavigation / bottom aliases retained).
• Bumps flutter_mcp_ui_core to ^0.4.0.

Fixed

• ThemeManager.getColorValue(slot) — falls back to the fromSeed-derived M3 28-role palette when the slot is absent from the bundle's raw theme.color map (spec §5.3 expects bundles to declare only seed plus a handful of overrides; the missing roles must derive). Previously the lookup only consulted _themeData = definition.toJson() (raw, no derive), so DSL bindings like theme.color.surfaceContainerHigh resolved to null for any bundle that omitted the role — even though toFlutterTheme().colorScheme.surfaceContainerHigh was filled correctly. The two paths now match. Light / dark schemes are cached; cache is invalidated on every setTheme / setThemeDefinition / resetTheme / reset / applyOverride restore. Semantic roles (success / warning / info and their on* variants) are not on Flutter's ColorScheme, so the fallback returns null for those — bundles must declare them explicitly.
• box (and the shared BoxDecorationResolver) — decoration: {color: ...} is no longer silently dropped when neither top-level color nor backgroundColor is supplied. The factory previously injected color: null into the flat property bag, and the resolver's flat-vs-nested override pass treated the containsKey('color') hit as an explicit erasure of the nested value. Now: (a) the factory only overlays color when the merged top-level value is non-null, and (b) the resolver ignores null entries during the override pass — they cannot shadow nested fields. Same null-tolerant treatment applies to gradient / image / border / borderRadius / boxShadow / shape / backdropBlur. Surface-toned boxes (e.g. decoration: {color: "surfaceContainerHigh"}) finally render against the M3 surface tonal scale rather than transparent.

0.4.4 - 2026-05-02 - M3 + Responsive consumption layer (bug fix)

0.3.0 announced "Material 3 + Responsive" but the runtime side was never actually wired up. 0.4.4 delivers the consumption surface so the previously advertised features finally work.

Fixed

• M3 token shorthand on text.variant, box.padding, card.shape, card.elevation, button.elevation, icon.size / sizeToken — resolves through the corresponding theme.<domain>.<token>.
• FormFactorScope auto-wrap on the runtime root, so AppSpacing.of(context) / AppTypography.of / AppIconSizes.of / AppDensity.of actually track the form factor.
• Per-form-factor property override map ({compact, medium, expanded, large, extraLarge, embedded, default}) resolves on every property, per spec § 14.2.
• Linux: event_listen_cb / event_cancel_cb return type aligned with FlMethodErrorResponse* so the plugin compiles against the current flutter_linux.h.

Notes

• Bumps flutter_mcp_ui_core to ^0.3.2 for the matching schema additions.

0.4.3 - 2026-05-01 - errorBoundary / errorRecovery onError spec violation fix

Fixed

• errorBoundary (spec §2.13.11) — onError child context was registering error (string) instead of the canonical event variable. Now registers event: {error, stack} so {{event.error}} and {{event.stack}} resolve as the spec specifies.
• errorRecovery (spec §2.13.12) — same variable-name violation; now registers event: {error, stack}. Stack trace is captured (was previously lost).
• errorBoundary was re-firing onError on every rebuild while the boundary remained in the error state. The action now dispatches exactly once per captured exception (in the post-frame callback that flips _hasError).

0.4.2 - 2026-05-01 - Tool response spec violation fix (§3.10 + §4.4.2)

Fixed

• §3.10 auto-merge — ToolActionExecutor now calls stateManager.mergeState(response) when the tool response is a Map and bindResult is not specified, instead of leaving fold to host code. Top-level keys of the response land directly on page state.
• §4.4.2 onSuccess/onError variable — child context now exposes the canonical event variable. {{event.<key>}} resolves to the response body inside onSuccess; inside onError, event is {code, message, details} per spec. Previously the runtime registered response / error (string), so the spec patterns silently failed.

Migration

• DSL written against the previous (non-spec) {{response.<key>}} / {{error.message}} shapes must move to {{event.<key>}} to keep working.

0.4.1 - 2026-04-30 - Template auto-registration + theme system fixes + spec alignment

Fixed

• RuntimeEngine now reads the templates block from the application / page definition during initialize and registers each entry into the TemplateRegistry (application scope for application roots, screen scope for standalone pages). Previously the block was silently ignored, so any { "type": "use", "template": "<name>" } reference in the DSL failed to resolve and the widget went unrendered.
• ThemeManager.flutterThemeMode now honours setHostBrightness for mode: 'system' resolution: when the embedder injects a brightness override, it returns ThemeMode.light / ThemeMode.dark accordingly instead of always emitting ThemeMode.system (which Flutter resolves against OS brightness only). AppPlayer-class hosts are "the system" for embedded bundles, so launcher light/dark toggles now propagate into nested MaterialApp instances.
• ThemeManager.toFlutterTheme(isDark: true) no longer falls back to the active (light) _definition when the bundle declares no dark variant — it now returns ThemeDefinition.defaultDark() so the M3 default dark scheme is used. Previously bundles with an empty theme block could only render light, regardless of host brightness.
• Template / itemTemplate instance state binding across close → reopen cycles. The singleton WidgetCache was retaining widget instances whose event-handler closures captured the prior session's destroyed RenderContext (StateManager, ActionHandler). After a host-driven close → reopen, the rebuilt UI tree showed cached widgets whose onTap mutations targeted the dead engine, so visible state never updated even though buttons appeared responsive. Fix has three parts working together:
  • Renderer._hasEventHandlers now recurses through child / children, so an ancestor container holding event-bound descendants is also flagged non-cacheable. Previously a linear / box wrapping an onTap button could be cached even though its subtree's closures captured a stale context.
  • 'use' is added to nonCacheableTypes. Each use site is an instance — its expansion MUST be a fresh widget subtree, not a shared cached widget across invocations or sessions.
  • MCPUIRuntime.destroy() now calls WidgetCache.instance.clear() to drop all cached entries from the dying session, so the next session starts with a clean cache and cannot inherit closures bound to a destroyed engine.
  • The same fix covers the list.itemTemplate (spec §9.6.1) instantiation path, since per-item expansions also produce fresh subtrees and the recursive event-handler check now catches buttons nested anywhere in the row template.

Changed (breaking — pre-launch spec alignment)

• ExtendedTemplateDefinition widget tree wrapper field renamed body → content to align with MCP UI DSL 1.3 §9.2.2 (the canonical key for the template's widget tree). The use-site invocation key (params: on the use widget) is unchanged.
• TemplateRegistry.isTemplateReference now accepts only the canonical type: "use". Legacy aliases (type: "template" / type: "useTemplate") are removed in line with the spec's no-alias-accretion policy. Bundles using the legacy types must migrate to type: "use".

0.4.0 - 2026-04-29 - Render inspector hook

• New MCPUIRuntime.withInspector(...) for editor tooling — pairs each rendered widget with its source JSON node. Standard constructor unchanged; no overhead when no inspector is supplied.

0.3.0 - 2026-04-28 - MCP UI DSL 1.3 (Material 3 + Responsive)

Changed (breaking)

• ThemeManager rewritten on top of strongly-typed ThemeDefinition from flutter_mcp_ui_core — drops the 1.2-era 11-slot raw map and parallel default scheme.
• Theme bindings use the new path scheme (theme.color.<slot>, theme.typography.<role>, theme.spacing.<token>, theme.shape.<family>, theme.elevation.<level>.shadow, theme.motion.duration.<key>). Legacy theme.colorScheme.*, theme.borderRadius.*, theme.spacing.medium, theme.elevation.small are removed.
• widget_factory semantic color slots aligned to M3 28-role + semantic family (no background / divider).
• DSL version constant now sourced from flutter_mcp_ui_core MCPUIDSLVersion (runtime's own DSLVersion enum removed).
• License changed from Apache-2.0 to MIT.

Added

• McpUiThemeBuilder — converts ThemeDefinition into Flutter ThemeData (ColorScheme, TextTheme, VisualDensity, CardThemeData, DialogThemeData).
• HCT-seed-derived default theme (SeedPalette.lightFromSeed / darkFromSeed).
• Page-level theme override — applyOverride(Map) deep-merges 14-domain JSON, returns restore callback (spec §5.7).
• Responsive form factor scaffold — FormFactor enum (compact / medium / expanded / large / embedded), FormFactorScope, ViewModeResolver priority chain.
• Four responsive token sets with .of(context) accessors — AppSpacing, AppIconSizes, AppTypography, AppDensity.
• Auto-adaptive navigation — drawer swaps to modal drawer (compact) / NavigationRail (medium) / permanent drawer (expanded+).
• New dependency: mcp_bundle ^0.3.0.

0.2.5

Bug Fixes

• Fixed resource subscription cleanup on runtime destroy to properly unsubscribe from all active resources

0.2.4

0.2.3

Documentation

• Added important build instructions for dynamic icons
• Documented the need for --no-tree-shake-icons flag when building apps with dynamic icons

0.2.2

Bug Fixes

• Fixed navigation state persistence to properly save and restore tab/navigation positions
• Added SharedPreferences support to CacheManager for actual disk persistence
• Fixed setState during build error in ApplicationShell navigation initialization

0.2.1

Bug Fixes

• Fixed state initialization issue where page states were not properly loaded
• Unified state management by removing duplicate StateService and using StateManager directly
• Fixed page state initialization in routing system

0.2.0

Refactoring

• Major internal refactoring for improved maintainability
• Enhanced code organization and structure
• Improved type safety and validation
• Better separation of concerns

0.1.0

Initial Release

• Comprehensive runtime for building dynamic, reactive UIs through JSON specifications
• Support for 77+ Flutter widgets across 9 categories
• Built-in state management with automatic UI updates
• Expression binding system with support for nested paths and transforms
• Action system (state, tool, batch, conditional, navigation)
• Multiple instance support for different MCP servers
• Tool executor injection for external API integration
• Custom widget registration support
• Custom transform registration
• Theme management with light/dark mode support
• Navigation and routing system
• Dialog and notification services
• Background service management
• Lifecycle management
• Service registry pattern
• Based on MCP UI DSL v1.0 specification