fix(ui): revert app-driven iframe width and send containerDimensions per ext-apps spec by aharvard · Pull Request #7300 · block/goose

aharvard · 2026-02-18T13:13:42Z

Summary

Fixes #6818 — Reverts #6376 and implements containerDimensions in the host context per the ext-apps spec.

Commit 1: Revert app-driven iframe width from #6376

PR #6376 let apps drive the container width via size-changed notifications. Per the spec and owtaylor's analysis, the host owns width in inline mode — apps should not resize it. This commit removes:

iframeWidth state and setIframeWidth
Width handling from handleSizeChanged (height-only now)
Conditional width styling — container is always width: 100%

Commit 2: Send `containerDimensions` in hostContext

Adds a getContainerDimensions() function that maps display modes to the spec's dimension modes. Each axis is independently fixed, flexible, or unbounded:

Mode	Spec Field	Meaning
Fixed	`width` / `height`	Host controls size, view fills it
Flexible	`maxWidth` / `maxHeight`	View controls size, up to the max
Unbounded	Field omitted	View controls size, no limit

Display mode → layout mapping:

Display Mode	Width	Height
`inline`	fixed	unbounded
`fullscreen`	fixed	fixed
`standalone`	fixed	fixed
`pip`	fixed	fixed

Container dimensions are measured from the actual container element via ResizeObserver and update reactively on resize.

Types (DimensionMode, DimensionLayout) are exported from McpApps/types.ts.

Test plan

npx tsc --noEmit passes
npx eslint clean
npx vitest run — 340/340 tests pass
Open an MCP app inline — should fill chat width, grow vertically
Resize the Goose window — app width should follow
Open an MCP app in standalone window — should fill the window
Resize standalone window — app should fill new size

The host owns container width in inline mode — apps should not resize the iframe width via onSizeChanged. This reverts the width-related changes from PR #6376: - Remove iframeWidth state and setIframeWidth - Remove width handling from handleSizeChanged (height-only now) - Always apply width: 100% and [&_iframe]:!w-full unconditionally - Remove maxWidth: 100% guard (no longer needed) Refs: #6818, #7256

Copilot

Pull request overview

Reverts app-driven iframe width sizing for MCP apps and adds containerDimensions to hostContext to align with the ext-apps container sizing spec.

Changes:

Remove width handling from size-changed and force inline iframe/container width to 100%.
Measure host container size with ResizeObserver and send containerDimensions based on display mode.
Export new dimension layout/types (DimensionMode, DimensionLayout) for mapping display modes to spec dimension semantics.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
ui/desktop/src/components/McpApps/types.ts	Adds exported dimension mode/layout types used to map display modes to spec sizing semantics.
ui/desktop/src/components/McpApps/McpAppRenderer.tsx	Removes app-driven width resizing, adds container measurement via `ResizeObserver`, and sends `containerDimensions` in `hostContext`.

ui/desktop/src/components/McpApps/McpAppRenderer.tsx

Add a getContainerDimensions() function that maps Goose display modes to the correct ext-apps spec containerDimensions shape: Inline mode: width (fixed) — host controls, app fills it maxHeight (flexible) — app controls height via size-changed, up to max Fullscreen / Standalone mode: width (fixed) — host controls, app fills it height (fixed) — host controls, app fills it Per the spec, each axis is independently fixed, flexible, or unbounded: - Fixed (height/width): Host controls size, view fills available space - Flexible (maxHeight/maxWidth): View controls size, up to the max - Unbounded (omitted): View controls size with no limit When a dimension is flexible, the host MUST listen for size-changed notifications and resize the iframe — which we already do for height in inline mode via onSizeChanged. Container dimensions are measured from the actual container element via ResizeObserver and update reactively on resize. Refs: #6818

Copilot

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

DOsinga · 2026-02-18T13:31:12Z

ui/desktop/src/components/McpApps/McpAppRenderer.tsx

not sure what this comment is for, maybe dorp?

The spec's rules for when to use width/height vs maxWidth/maxHeight vs omitting fields are a bit hard to follow, so I abstracted it into a layout map using more intuitive terms: fixed, flexible, unbounded. We don't have a flexible case yet, but I wanted to capture it now so we don't have to re-derive it later.

DOsinga · 2026-02-18T13:50:04Z

ui/desktop/src/components/McpApps/McpAppRenderer.tsx

we could collapse these into one if

DOsinga · 2026-02-18T13:54:50Z

ui/desktop/src/components/McpApps/McpAppRenderer.tsx

eh, isn't that just width/height

yep, simplified to just contentRect.width/height — we don't need logical properties for vertical writing modes.

DOsinga · 2026-02-18T13:55:46Z

ui/desktop/src/components/McpApps/types.ts

+  width: DimensionMode;
+  height: DimensionMode;
+}
+


shouldn't we get these from the server spec?

The spec exports the containerDimensions shape on McpUiHostContext but not a DimensionMode/DimensionLayout type — those are our internal mapping for deciding which fields to populate per display mode. If the spec ever exports them we'll switch.

…ontentRect

* origin/main: feat: add GOOSE_SUBAGENT_MODEL and GOOSE_SUBAGENT_PROVIDER config options (#7277) fix(openai): support "reasoning" field alias in streaming deltas (#7294) fix(ui): revert app-driven iframe width and send containerDimensions per ext-apps spec (#7300) New OpenAI event (#7301) ci: add fork guards to scheduled workflows (#7292) fix: allow ollama input limit override (#7281) chore: show important keys for provider configuration (#7265) fix: subrecipe relative path with summon (#7295) fix extension selector not displaying the correct enabled extensions (#7290) Use the working dir from the session (#7285) Fix: Minor logging uplift for debugging of prompt injection mitigation (#7195) feat(otel): make otel logging level configurable (#7271) docs: add documentation for Top Of Mind extension (#7283) Document gemini 3 thinking levels (#7282) docs: stream subagent tool calls (#7280) Docs: delete custom provider in desktop (#7279) # Conflicts: # ui/desktop/src/components/McpApps/McpAppRenderer.tsx

* origin/main: docs: remove ALPHA_FEATURES flag from documentation (#7315) docs: escape variable syntax in recipes (#7314) docs: update OTel environment variable and config guides (#7221) docs: system proxy settings (#7311) docs: add Summon extension tutorial and update Skills references (#7310) docs: agent session id (#7289) fix(gemini-cli): restore streaming lost in #7247 (#7291) Update more instructions (#7305) feat: add Moonshot and Kimi Code declarative providers (#7304) fix(cli): handle Reasoning content and fix streaming thinking display (#7296) feat: add GOOSE_SUBAGENT_MODEL and GOOSE_SUBAGENT_PROVIDER config options (#7277) fix(openai): support "reasoning" field alias in streaming deltas (#7294) fix(ui): revert app-driven iframe width and send containerDimensions per ext-apps spec (#7300) New OpenAI event (#7301) ci: add fork guards to scheduled workflows (#7292)

Copilot AI review requested due to automatic review settings February 18, 2026 13:13

Copilot started reviewing on behalf of aharvard February 18, 2026 13:14 View session

Copilot AI reviewed Feb 18, 2026

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ui/desktop/src/components/McpApps/McpAppRenderer.tsx Show resolved Hide resolved

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aharvard force-pushed the aharvard/revert-iframe-width-add-container-dimensions branch from 21cf7dd to afc8480 Compare February 18, 2026 13:19

aharvard requested a review from Copilot February 18, 2026 13:25

Copilot started reviewing on behalf of aharvard February 18, 2026 13:26 View session

Copilot AI reviewed Feb 18, 2026

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This was referenced Feb 18, 2026

fix(ui): prevent MCP app iframe from staying stuck at compressed width #7256

Closed

Resize goose desktop shrink the mcp app and it never grows back. #6818

Closed

aharvard requested review from DOsinga and zanesq February 18, 2026 13:29

DOsinga approved these changes Feb 18, 2026

View reviewed changes

refactor: collapse guard into single if, simplify ResizeObserver to c…

d2a45e1

…ontentRect

aharvard added this pull request to the merge queue Feb 18, 2026

Merged via the queue into main with commit 79af1cf Feb 18, 2026
20 checks passed

aharvard deleted the aharvard/revert-iframe-width-add-container-dimensions branch February 18, 2026 14:50

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fix(ui): revert app-driven iframe width and send containerDimensions per ext-apps spec#7300

fix(ui): revert app-driven iframe width and send containerDimensions per ext-apps spec#7300
aharvard merged 3 commits intomainfrom
aharvard/revert-iframe-width-add-container-dimensions

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aharvard commented Feb 18, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Commit 1: Revert app-driven iframe width from #6376

Commit 2: Send containerDimensions in hostContext

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aharvard commented Feb 18, 2026 •

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Commit 2: Send `containerDimensions` in hostContext