No SDK API changes since 1.7.2.
Examples:
- Add lazy-auth-server example (#679)
- Publish lazy-auth-server to npm (added to publish workflows)
Also syncs example dependency ranges to ^1.7.0 (output of npm run bump).
No SDK API changes since 1.7.1.
Examples:
- pdf-server: switch pdf-lib to maintained @cantoo/pdf-lib fork (#651)
- bump example transitives to latest patches (#658)
* feat(pdf-server): refit on inline→fullscreen + pinch-to-zoom in fullscreen
Two related fixes for the fullscreen reading experience:
1) Inline → fullscreen left the page at the cramped inline scale.
computeFitToWidthScale() returned null when the natural page
already fit (availableWidth >= pageWidth), so going from a
narrow inline iframe (~67%) to a wide fullscreen container
produced null → no rescale. Now caps at min(1.0, fit) so the
refit handler sees 1.0 ≠ 0.67 and re-renders. Display-mode
handling moves before the containerDimensions refit so the
.fullscreen padding lands before we measure clientWidth, and
the inline→fullscreen edge triggers refit explicitly (some
hosts send displayMode without containerDimensions).
2) Pinch-to-zoom in fullscreen. Two input paths:
- wheel + ctrlKey → trackpad pinch (Chrome/FF/Edge/Safari).
exp(-deltaY/100) per pdf.js; 150ms settle then commit.
- two-finger touch → mobile. Distance ratio against touchstart;
commit on touchend, revert on touchcancel.
Both apply a CSS transform to .page-wrapper for live feedback,
then commit one renderPage() at gesture end (renderPage is
heavy: PDF.js raster + TextLayer + AnnotationLayer rebuild).
touch-action: pan-x pan-y on the fullscreen canvas-container
keeps native panning working while we own the pinch.
Incidental: resetZoom (Cmd+0) now snaps to fit, not blindly 1.0,
so it doesn't overflow a narrow inline iframe; ZOOM_MIN/MAX
constants; shared pageWrapperEl ref.
* test(pdf-viewer-zoom): start narrow — basic-host doesn't emit containerDimensions on resize
The first test loaded at 1400w then resized to 500w expecting the
viewer to refit, but basic-host only sends containerDimensions at
init (implementation.ts:297) — never on window resize. Start narrow
so the initial fit lands <100%, then widen + fullscreen. Matches
the webtop verification flow that confirmed 67% → 100%.
* fix(pdf-server): drive fullscreen refit from ResizeObserver, not host messages
The displayMode hook ran refitToWidth() but Claude Desktop resizes
the iframe element AFTER (or independently of) sending the displayMode
update — clientWidth was still the inline width when we measured.
ResizeObserver on the canvas-container fires after the iframe has
actually laid out at the new size, so the measurement is fresh.
Gated to width-growth only: in inline mode renderPage() →
requestFitToContent() → host shrinks iframe to page width, which
would otherwise loop the scale down to ZOOM_MIN. Growth-only covers
inline→fullscreen and window-widen without the feedback loop.
* fix(basic-host): emit containerDimensions on iframe resize
Per spec, hosts notify views of container dimension changes via
host-context-changed. basic-host only sent containerDimensions once
at init — never on window resize or after the fullscreen panel
toggle. ResizeObserver on the iframe sends {width, maxHeight: 6000}
on every layout change; height stays flexible so views can keep
driving it via sendSizeChanged.
Doesn't replace the viewer-side ResizeObserver (defensive against
hosts we don't control), but makes the reference host spec-compliant.
* fix(pdf-server): scale UP to fill width in fullscreen, not just down
The previous fit cap of 1.0 meant a 612pt page in a 1400px fullscreen
container stayed at 100% — natural size, acres of empty space.
Fullscreen now caps at ZOOM_MAX so the page fills the available
width. Inline keeps the 1.0 cap (the iframe sizes to the page via
sendSizeChanged; growing past 1.0 would just make the iframe huge).
Exit-fullscreen refits back down to ≤1.0; if userHasZoomed (so
refit no-ops) fall back to requestFitToContent so the iframe still
shrinks to whatever scale they left it at.
* test(pdf-viewer-zoom): expect fullscreen to fill width (>100%), pinch out
Fullscreen fit now scales up past 100%, so the entering-fullscreen
assertion is >inlineZoom+50, not =100. The pinch test pinches OUT
(deltaY>0) so it doesn't immediately hit ZOOM_MAX from a ~220%
starting point.
* fix(pdf-server): fullscreen fit-to-PAGE, not fit-to-width
Fit-to-width on a wide screen filled the width but left the page
scrolling vertically — "fits" should mean the whole page is visible.
computeFitScale (renamed) now returns min(widthFit, heightFit) in
fullscreen so the page sits centred without scroll. Inline keeps
fit-to-width capped at 1.0 (height is host-driven via sendSizeChanged).
ResizeObserver now reacts to height changes too in fullscreen — the
inline width-growth-only gate stays (requestFitToContent loop guard),
but in fullscreen requestFitToContent early-returns so any size change
is safe to refit on.
e2e: assert no overflow in fullscreen instead of a magic zoom %.
* fix(pdf-server): respect safe-area insets in fullscreen fit-to-page
The host's chat input / home indicator overlays the bottom of the
fullscreen iframe (reported via safeAreaInsets). The toolbar already
honoured top/left/right; the canvas-container now adds the bottom +
side insets to its padding so the page sits above the overlay.
computeFitScale subtracts padding, so fit-to-page lands clear.
ResizeObserver watches the content box, so inset changes re-trigger
the fit.
* fix(pdf-server): clear pinch transform in same frame as canvas resize
commitPinch cleared the CSS transform BEFORE renderPage's first
await — for one frame the page snapped back to the old rendered
size, then jumped forward when the canvas resized. renderPage now
clears the transform immediately after setting canvas.style.width/
height, so the size handoff is atomic.
Also bump the wheel settle timer 150→200ms; slow trackpad pinches
can leave >150ms gaps and would commit mid-gesture.
* fix(pdf-server): no blank flash on pinch commit; clamp Ctrl+mousewheel; basic-host observer cleanup
Three review follow-ups:
1) Snap on pinch release: setting canvasEl.width clears the backing
store, so between the resize and page.render() completing the
page was blank. Snapshot the old bitmap first and drawImage it
scaled as a placeholder; the real render paints over it. Gated
on a transform being present so page-nav renders aren't affected.
2) Ctrl + physical mouse wheel sent deltaY≈±100 → exp(±1)≈2.7× per
notch, slamming straight to ZOOM_MIN/MAX. Clamp per-event delta
to ±25 (≈±28% per notch); trackpad pinch deltas are ~±1-10 so
the clamp is a no-op there.
3) basic-host's iframe ResizeObserver had no disposal path. Chained
disconnect() into appBridge.onclose (Protocol base class hook).
* simplify(pdf-server): pinch snap was transform-origin mismatch, not bitmap
The snap on pinch release was the page jumping vertically:
transform-origin: center center scales around the wrapper's middle,
but the flex container is align-items: flex-start so on commit the
canvas grows from the TOP. Preview top edge moved up; committed top
edge stays put → jump down. transform-origin: 50% 0 matches the
layout anchor, no jump.
Drop the canvas-snapshot placeholder (over-engineered, wrong fix),
the dead transition='' lines (.page-wrapper has no CSS transition),
and the containerDimensions→refit hook (ResizeObserver covers actual
size changes; the host message isn't load-bearing).
Changes since 1.2.1:
- fix(schemas): import from zod/v4 to match SDK's zod API (#548)
- test(e2e): fix no-op security injection test via frames[] traversal (#540)
Change `sandbox.ts` imports from relative paths into `dist/` to use the
proper `@modelcontextprotocol/ext-apps/app-bridge` package entry point.
This aligns the example with how external consumers would import from
the package.
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
* chore: bump ext-apps to 1.1.2
Changes since 1.1.1:
- feat: add ui/download-file method for host-mediated file downloads (#475)
- pdf-server: robust path validation + folder/file root support (#497)
- ci: auto-fix prettier formatting in pre-commit hook and CI (#498)
* fix: sync local SDK build into node_modules for examples
npm workspaces hoists example dependencies to the root node_modules,
but installs the published registry copy of @modelcontextprotocol/ext-apps
instead of linking to the local source. This causes type-check failures
when examples use features not yet published to npm.
Add scripts/link-self.mjs which copies the freshly-built dist/ and
package.json into the hoisted node_modules copy after each SDK build,
ensuring examples always type-check against the latest local types.
See: https://github.com/npm/feedback/discussions/774
* Revert "fix: sync local SDK build into node_modules for examples"
This reverts commit e3387e8434f3def030f5a223a70632092c929119.
Bug fixes / improvements since 1.1.0:
- fix: add audio/video support for basic-host (#460)
- fix(pdf-server): remove page-loading overlay (#493)
- pdf-server: remove domain allowlist, require HTTPS only (#487)
- Set audioSession.type to playback in sheet music app (#489)
- Add MCPB packaging and Claude Code plugin for pdf-server (#491)
* chore: bump ext-apps to 1.1.0
Features:
- registerAppResource now returns the registered resource (#370)
- Accept UIResourceMeta in both resources/list and resources/read (#410)
- callServerTool throws helpful error when called with a string (#449)
- Add double-connect guard to prevent protocol message handling errors (#450)
Bug fixes:
- Only ignore messages that lack jsonrpc 2.0 in message-transport (#448)
- Align basic-host dark mode styles (#438)
Spec:
- Change Host <> Sandbox communication protocol to SHOULD (#435)
- Clarify UIResourceMeta in both list and read responses (#410)
* fix(debug-server): add missing npm package config (main, bin, types, exports)
Align debug-server package.json with all other server examples:
- main: dist/server.js (was server.ts)
- types: dist/server.d.ts
- bin: mcp-server-debug -> dist/index.js
- exports with types
- files: only dist (remove source server.ts)
* Clarify spec and SDK: accept UIResourceMeta in both resources/list and resources/read
The spec defines UIResource with _meta.ui, implicitly as an extension of the Resource type (resources/list), but examples and practice place _meta.ui on TextResourceContents (resources/read). The registerAppResource helper accepts _meta.ui in its config (which ends up in resources/list), but examples only return said _meta.ui from resources/read — and current hosts might be just ignoring it.
This change:
- Adds a 'Metadata Location' subsection to the draft spec explicitly stating that _meta.ui is valid on both the resource listing entry AND the content item, with content-item taking precedence.
- Updates the spec example to show _meta on the resource declaration (resources/list).
- Updates the CSP construction example to reference both locations.
- Clarifies McpUiAppResourceConfig JSDoc: _meta here appears in resources/list and serves as a listing-level fallback for when content items omit _meta.ui.
- Fixes the map-server example comment that incorrectly stated _meta must only be on the content item.
* Add McpUiReadResourceResult type for UI metadata in resources/read
* basic-host: support UIResourceMeta fallback from resources/list
---------
Co-authored-by: Claude <noreply@anthropic.com>
* fix(examples): use npm reference for ext-apps dependency
Replace local path '../..' with '^1.0.0' npm reference in all example
packages. The local path was accidentally published to npm, causing
npm install to hang when installing server-* packages.
Bump versions to 1.0.1 for all public packages to fix the published
versions.
Fixes npm install hanging issue in dependent projects like
example-remote-server.
Note: npm workspaces automatically resolves the dependency to the
local package during development, so no overrides are needed.
* fix: update zod to 4.x in transcript-server and fix update-lock:docker script
- Update transcript-server to use zod ^4.1.13 for compatibility
- Fix update-lock:docker script to properly clean workspace node_modules
- Regenerate package-lock.json with clean npmjs.org URLs
* chore: add stable spec release 2026-01-26
- Use git mv to copy specification from draft to specification/2026-01-26/apps.mdx (preserves history)
- Update status from 'Draft' to 'Stable (2026-01-26)'
- Add specification version table to README
- Update Resources section with links to both stable and draft specs
* chore: bump version to 1.0.0
- Update main package version from 0.4.2 to 1.0.0
- Update all example package versions to 1.0.0
- Regenerate package-lock.json
* prettier
* chore: align protocol version with spec release 2026-01-26
- Add 'Protocol Version: 2026-01-26' to spec header
- Update LATEST_PROTOCOL_VERSION from '2025-11-21' to '2026-01-26'
- Update spec examples to use '2026-01-26' protocol version
- Add '2025-11-21' to SUPPORTED_PROTOCOL_VERSIONS for backwards compatibility
* chore: update spec references to stable 2026-01-26
- Update typedoc.config.mjs navigation link
- Update docs/overview.md spec links (10 occurrences)
- Update plugins/mcp-apps/skills/create-mcp-app/SKILL.md spec link
- Update src/spec.types.ts @see links
- Update AGENTS.md spec path
- Regenerate src/generated/schema.ts with updated links
* chore: simplify versioning - first stable release
- Remove backwards compatibility version (2025-11-21) - this is the first stable release
- Remove redundant 'Protocol Version' header - spec version IS the protocol version
* chore: add history reference comment to stable spec
* Adding a simple (bad) pdf icon for directory (#330)
* chore: bump version to 0.4.2
- Update package version from 0.4.1 to 0.4.2
- Pin @types/node to 22.10.0 for dev compatibility
- Override seroval to ^1.4.1 to fix security vulnerabilities
- Use '*' for workspace SDK dependency (works with unpublished versions)
* fix(e2e): update Map Server display name to CesiumJS Map Server (#324)
* fix(test): update map-server test to expect 'CesiumJS Map Server'
The server name was renamed but the E2E test config was not updated.
* fix: change in another file
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Olivier Chafik <ochafik@anthropic.com>
* feat(server): add getUiCapability helper for capability negotiation (#313)
* feat(server): add hasUiSupport/getUiCapability for experimental+extensions
Support double-tagging for MCP Apps capability negotiation:
- Check both experimental and extensions fields in client capabilities
- Add hasUiSupport() to easily check if client supports MCP Apps
- Add getUiCapability() to retrieve the capability settings
- Update spec to document both capability locations
This enables forward compatibility as MCP transitions from experimental
to the extensions field (SEP-1724).
Claude-Generated-By: Claude Code (cli/claude-opus-4-5=100%)
Claude-Steers: 0
Claude-Permission-Prompts: 0
Claude-Escapes: 0
* fix: update @types/node version in package-lock.json
Replace invalid 22.19.5/22.19.6/22.19.7 versions with valid 22.19.3
* docs(spec): clarify hosts SHOULD double-tag, servers SHOULD check both
- Hosts SHOULD advertise capabilities in both experimental and extensions
- Servers SHOULD check both locations, preferring extensions when present
- Updated example to show double-tagging pattern
* chore: remove double-tagging recommendation, keep hasUiSupport helper
Reverts the spec changes that recommended clients double-tag capabilities
in both experimental and extensions fields. The helper functions remain
as they're useful for checking capability in either location.
* refactor(server): simplify to only getUiCapability, remove hasUiSupport
- Remove hasUiSupport function (use getUiCapability directly)
- Remove double-tagging logic (only check extensions field)
- Add ClientCapabilitiesWithExtensions type using SDK's ClientCapabilities
- Update spec to use getUiCapability
- Simplify tests
* fix: update @see link to getUiCapability
* refactor(server): inline ClientCapabilitiesWithExtensions type in getUiCapability
* refactor: move McpUiClientCapabilities to spec.types.ts
* fix: update playwright docker image to v1.58.0
* fix: use -i instead of -it for docker commands (no TTY needed)
* fix: Python server dependency resolution and Docker host validation (#333)
* fix(say-server): add --index flag to uv run for PyPI resolution
The pocket-tts dependency wasn't resolving without explicit --index flag
when invoked via npm scripts.
* fix(qr-server): allow Docker bridge IP in transport security
Add 172.17.0.1:* to allowed_hosts to fix 421 Misdirected Request errors
when the server is accessed from Docker containers.
* feat(basic-host): Add theme toggle and MCP style variables (#336)
* feat(basic-host): add theme toggle and MCP style variables
Add theme support to basic-host example:
- theme.ts: Global theme manager with light/dark toggle
- host-styles.ts: Full set of MCP CSS variables using light-dark()
- ThemeToggle component with sun/moon icons
- Theme-aware CSS using CSS custom properties
- Pass theme + styles to apps via hostContext
- Notify apps when theme changes via sendHostContextChange
Apps now receive:
- hostContext.theme: 'light' | 'dark'
- hostContext.styles.variables: All 60+ MCP CSS variables
- onhostcontextchanged notifications when theme changes
* test: update e2e goldens for theme changes
* [MCP Apps] Add appCapabilities.availableDisplayModes documentation to spec (#331)
* Add appCapabilities.availableDisplayModes documentation to spec
Document the availableDisplayModes field in McpUiAppCapabilities that allows
apps to declare which display modes they support. This enables hosts to
compute the intersection of host and app capabilities and only offer
appropriate display mode controls.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Address PR review feedback
- Change "Guest UI" to "View" terminology
- Add "View" prefix to availableDisplayModes heading for disambiguation
- Remove intersection logic - host only checks its own supported modes
- Remove assumption that apps must support inline mode
- Simplify host behavior to honor/reject based on its own capabilities
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Add appCapabilities.availableDisplayModes to types
- Add `availableDisplayModes` field to `McpUiAppCapabilities` so apps can
declare which display modes they support
- Change `HostContext.availableDisplayModes` type from `string[]` to
`McpUiDisplayMode[]` for type safety
- Regenerate schemas
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Address Olivier's feedback - consolidate display mode docs
- Remove separate "App Capabilities" section for availableDisplayModes
- Add display mode requirements to existing ui/request-display-mode section:
- Host MUST NOT switch View to mode not in appCapabilities.availableDisplayModes
- Host MAY decline requests from Views that didn't declare modes
- View MUST declare supported modes during initialization
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Restore McpUiAppCapabilities docs and fix display mode clause
- Restore McpUiAppCapabilities interface documentation with availableDisplayModes
- Restore "View MUST check if the requested mode is in availableDisplayModes
from host context" clause that was accidentally removed
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Create unified Display Modes section
Consolidate all display mode documentation into a single section:
- Display mode types (inline, fullscreen, pip)
- Declaring support from View (appCapabilities.availableDisplayModes)
- Declaring support from Host (HostContext.availableDisplayModes)
- Requesting changes (ui/request-display-mode)
- Notifying changes (ui/notifications/host-context-changed)
- All MUST/SHOULD requirements for View and Host behavior
The ui/request-display-mode in Requests section now references
the Display Modes section for behavior details.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Remove mode coercion clause from display modes
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Regenerate schemas with correct version
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
---------
Co-authored-by: Claude <noreply@anthropic.com>
* feat(say-server): add light/dark theme support (#338)
- Add importmap entry for main SDK exports (applyDocumentTheme, etc.)
- Import and apply host theme and styles on context changes
- Apply initial host context theme/styles when app connects
- Update CSS to use [data-theme="dark"] selector for host-provided themes
- Keep @media prefers-color-scheme as fallback for standalone mode
- Add color-scheme meta tag for native element theming
* fix: followup app -> view terminology (#339)
* chore: husky env fix, version pins, update-lock:docker script (#341)
* fix(husky): load Node.js env for GUI apps + add update-lock:docker script
Cherry-picked non-e2e changes from ochafik/fix-e2e-flaky-tests:
- Load nvm/fnm/volta/homebrew paths in pre-commit for GitHub Desktop
- Add update-lock:docker script to regenerate lockfile with public registry
* pin package versions for dev compatibility
- solid-js: 1.9.10
- caniuse-lite: 1.0.30001763
- cheerio: 1.1.2
- electron-to-chromium: 1.5.267
- @playwright/test: 1.57.0
- playwright: 1.57.0
- playwright-core: 1.57.0
* regen
* fix: pin @types/node to existing version and regenerate lockfile
- Fix @types/node 20.19.28 -> 20.19.27 (typo, version didn't exist)
- Regenerate package-lock.json to resolve versions available on both
public npm and Anthropic artifactory registries
* fix(basic-server-solid): bump solid-js 1.9.10 -> 1.9.11 to fix seroval vulnerabilities
* fix: pin seroval to 1.4.1 for dev compatibility
* Refactor server startup functions
Rename `startServer` to `startStreamableHTTPServer` and add a new
`startStdioServer` helper to make the transport type explicit. Remove
the `ServerOptions` interface in favor of reading `PORT` directly from
the environment inside the function (defaulting to `3001`).
Also update Python examples to default to port `3001` for consistency.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Support full-file inclusion in synced code snippets
Previously, the script only supported extracting regions from `.ts/.tsx`
files using the `#regionName` syntax. Now it also supports including
entire files without a region specifier, enabling sync of any file type
(JSON, YAML, shell scripts, etc.) into documentation.
Changes:
- Make `#regionName` optional in the `source=""` attribute
- Accept any fence language (not just `ts`/`tsx`)
- Simplify cache to flat map with composite keys
- Add validation error for region extraction on non-TypeScript files
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Rewrite Quickstart guide with type-checked code examples
Rewrites the Quickstart tutorial to provide a more focused, step-by-step
introduction to building MCP Apps. The guide now uses synced code fences
that pull from `examples/quickstart/`, ensuring all code shown in the
documentation is type-checked and tested.
Key improvements:
- Clearer project setup instructions with explicit commands
- Streamlined explanations of the tool + resource registration pattern
- Added screenshot showing the completed app
- E2E test coverage validates the example works end-to-end
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Add MCP Apps Overview document
Adds `docs/overview.md` covering the core concepts: architecture,
lifecycle, UI resources, bidirectional communication, theming, display
modes, and security. Includes mermaid flowchart and sequence diagrams.
Also adds the `@boneskull/typedoc-plugin-mermaid` TypeDoc plugin for
mermaid diagram support. However, the plugin handles HTML entities from
TypeDoc incorrectly, so `scripts/typedoc-plugin-fix-mermaid-entities.mjs`
decodes HTML entities before the plugin processes them.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Add Agent Skills installation guide
Add `docs/agent-skills.md` with installation instructions for multiple AI
coding agents including Claude Code, VS Code/Copilot, Gemini CLI, Cline,
and Goose. The guide provides three installation methods: Claude Code
plugin, Vercel Skills CLI (`npx skills add`), and manual installation.
Update `README.md` to link to the new guide and reframe the plugin
section around the broader "Agent Skills" concept.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Polish OpenAI migration reference for readability
Add framing prose to the migration guide to improve navigation:
- Expanded intro describing document purpose and how to use it
- Added note about features marked "Not yet implemented"
- Added brief transition sentences before Server-Side and Client-Side sections
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Fix mermaid diagram arrowheads not rendering
The `@boneskull/typedoc-plugin-mermaid` creates both dark and light theme
variants of each diagram, each with identical marker IDs (e.g., `#arrowhead`).
When mermaid renders SVGs at runtime, lines reference `url(#arrowhead)`, but
the browser resolves this to the first match in document order — the hidden
dark-theme SVG — causing arrows to be invisible.
The fix removes dark-theme `<div class="mermaid dark">` elements at build time,
leaving only one SVG per diagram with unique marker IDs. A CSS filter
(`filter: invert(1) hue-rotate(180deg)`) handles dark mode styling instead.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* fix(docs): improve OpenAI migration guide accuracy (#349)
- Add missing setOpenInAppUrl API to 'Not Yet in MCP Apps' section
- Clarify Event Handling table: specify exact OpenAI properties
(toolInput/toolOutput) instead of vague 'window.openai.*'
- Improve notes to distinguish sync property reads vs callbacks
* Add Testing MCP Apps guide
Document how to test MCP Apps using `basic-host` and MCP Apps-compatible
hosts like Claude.ai and VS Code Copilot. Cover debugging features for
`basic-host`, and using `cloudflared` to expose local servers for remote
hosts.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Fix `onhostcontextchanged` handler invocation in examples
`App.onhostcontextchanged` is a setter-only property with no getter.
TypeScript doesn't prevent reading from setter-only properties, so
`app.onhostcontextchanged?.(ctx)` compiles but silently returns
`undefined` at runtime.
Extract the handler into a named `handleHostContextChanged()` function
and call it directly after `connect()`, matching the pattern used in
`basic-server-vanillajs` and other examples.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Expand Agent Skills guide
Add intro explaining what Agent Skills are and link to the two skill
files (`create-mcp-app`, `migrate-oai-app`). Reorganize headings and add
"Invoke a Skill" and "Test Your App" sections. Update `README.md` link
text and add tip to quickstart suggesting agent skills as an alternative.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* fix(e2e): improve test stability and developer experience (#337)
* fix(e2e): add masks for dynamic content and increase timeouts for slow servers
- Add HOST_MASKS for Tool Input/Result panels with dynamic timestamps
- Add say-server to SLOW_SERVERS (10s) for TTS model download
- Add say-server to EXTRA_WAIT_MS (30s) in generate-grid-screenshots
* feat: add update-lock:docker script to regenerate lockfile with public registry
* pin package versions for dev compatibility
* feat(basic-host): add ?theme=hide query param to hide theme toggle in screenshots
- Add hideThemeToggle param to getQueryParams()
- Conditionally render ThemeToggle based on ?theme=hide
- Update e2e tests to use ?theme=hide for consistent screenshots
* update screenshots
* update screenshots
* fix(husky): load Node.js environment for GUI apps like GitHub Desktop
* fix(e2e): increase map-server wait time to 15s for tile loading
* fix(e2e): increase waitForAppLoad timeout to 30s for nested iframe loading
* ci: add workflow to update e2e snapshots
* ci: trigger snapshot update on push to this branch
* chore: update e2e snapshots [skip ci]
* ci: trigger CI after snapshot update
* style: fix prettier formatting in update-snapshots workflow
* fix: pin seroval, seroval-plugins, and solid-js for dev compatibility
---------
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
* Improve README structure and clarity
Add "Why MCP Apps?" section to explain the motivation upfront. Reorganize
the "How It Works" section to lead with tool definition. Rename "Overview"
to "Using the SDK" and add "For" prefix to audience headings.
Restructure the Examples section with clearer subsections for running
examples with `basic-host` vs MCP clients using stdio transport. Move the
`qr` server note outside the collapsed details block.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Add Codex and Goose to documentation
Add Codex to the list of agents supporting skills in `agent-skills.md`.
Add Goose to the list of supported clients in `testing-mcp-apps.md` and
rename "VS Code Copilot" to "VS Code (Insiders)" for accuracy.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* chore: regenerate lockfile with public registry, use ^0.4.2 for ext-apps deps
* fix: update quickstart example to use workspace reference
* chore: remove internal registry references from lockfile
* feat(ci): add /update-snapshots comment trigger for PRs
- Comment '/update-snapshots' on any PR to update E2E snapshots
- Adds rocket reaction to acknowledge the command
- Comments back with result (updated or no changes needed)
- Removes hardcoded branch trigger
- Keeps workflow_dispatch for manual runs
* docs: document /update-snapshots PR comment trigger
* fix: pin @hono/node-server to 1.19.7 for dev compatibility
SDK 1.25.3 requires @hono/node-server@^1.19.9 which doesn't exist
on the public npm registry (latest is 1.19.7).
* fix: pin @modelcontextprotocol/sdk to 1.25.2
SDK 1.25.3 has broken dependency on @hono/node-server@^1.19.9
which doesn't exist on public npm registry.
* fix: restore flexible SDK peerDep range (^1.24.0)
devDependencies stays pinned to 1.25.2 for our builds,
but peerDependencies should allow users flexibility.
* fix: pin @types/node to avoid unpublished versions
- Pin quickstart @types/node to 22.19.5 (latest public 22.x)
- Add @types/node override to root package.json
- Regenerate lockfile with public registry only
---------
Co-authored-by: Tobin South <tobin.south@gmail.com>
Co-authored-by: Liad Yosef <liady@users.noreply.github.com>
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: martinalong <martinalong10@gmail.com>
Co-authored-by: Ido Salomon <idosalomon@gmail.com>
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
* fix(e2e): add masks for dynamic content and increase timeouts for slow servers
- Add HOST_MASKS for Tool Input/Result panels with dynamic timestamps
- Add say-server to SLOW_SERVERS (10s) for TTS model download
- Add say-server to EXTRA_WAIT_MS (30s) in generate-grid-screenshots
* feat: add update-lock:docker script to regenerate lockfile with public registry
* pin package versions for dev compatibility
* feat(basic-host): add ?theme=hide query param to hide theme toggle in screenshots
- Add hideThemeToggle param to getQueryParams()
- Conditionally render ThemeToggle based on ?theme=hide
- Update e2e tests to use ?theme=hide for consistent screenshots
* update screenshots
* update screenshots
* fix(husky): load Node.js environment for GUI apps like GitHub Desktop
* fix(e2e): increase map-server wait time to 15s for tile loading
* fix(e2e): increase waitForAppLoad timeout to 30s for nested iframe loading
* ci: add workflow to update e2e snapshots
* ci: trigger snapshot update on push to this branch
* chore: update e2e snapshots [skip ci]
* ci: trigger CI after snapshot update
* style: fix prettier formatting in update-snapshots workflow
* fix: pin seroval, seroval-plugins, and solid-js for artifactory compatibility
---------
Co-authored-by: github-actions[bot] <github-actions[bot]@users.noreply.github.com>
Rewrites the Quickstart tutorial to provide a more focused, step-by-step
introduction to building MCP Apps. The guide now uses synced code fences
that pull from `examples/quickstart/`, ensuring all code shown in the
documentation is type-checked and tested.
Key improvements:
- Clearer project setup instructions with explicit commands
- Streamlined explanations of the tool + resource registration pattern
- Added screenshot showing the completed app
- E2E test coverage validates the example works end-to-end
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* feat(basic-host): add theme toggle and MCP style variables
Add theme support to basic-host example:
- theme.ts: Global theme manager with light/dark toggle
- host-styles.ts: Full set of MCP CSS variables using light-dark()
- ThemeToggle component with sun/moon icons
- Theme-aware CSS using CSS custom properties
- Pass theme + styles to apps via hostContext
- Notify apps when theme changes via sendHostContextChange
Apps now receive:
- hostContext.theme: 'light' | 'dark'
- hostContext.styles.variables: All 60+ MCP CSS variables
- onhostcontextchanged notifications when theme changes
* test: update e2e goldens for theme changes
* feat(examples): add debug-server example
A comprehensive debug/development server for testing MCP Apps SDK features:
- Vanilla TypeScript UI with collapsible panels
- Message visualization (sent, received, errors)
- Server tool calling interface
- Multiple tool endpoints for testing
* refactor(debug-server): convert to React
- Replace vanilla TypeScript with React components
- Add comprehensive Host Styles panel showing all CSS variables grouped by category
- Use React hooks (useApp, useHostStyles, useAutoResize)
- Cleaner state management with useReducer for event log
- Collapsible sections for better organization
- CSS modules for scoped styling
* fix(debug-server): correct server name in main.ts
* Revert "refactor(debug-server): convert to React"
This reverts commit 5d22d2daa9a98ba412892447202ef10fbdb62f5b.
* fix(debug-server): update default values for multipleBlocks and includeMeta
* fix(debug-server): correct serve script and server name
- serve script now runs main.ts instead of server.ts
- Updated server name to 'Debug Server'
- Fixed npx command in comment
* fix: increase maxHeight to 6000px and add tools capability to debug app
- basic-host: Increase maxHeight from 600 to 6000px
- debug-server: Add tools capability to enable oncalltool/onlisttools handlers
* fix(debug-server): use consistent callback names for event tracking
Event types now match callback names (ontoolinput, ontoolresult, etc.)
so the Callback Status panel shows correct counts and payloads.
* feat(debug-server): add Update (Image) button for model context
* feat(debug-server): add expandable event log entries
- Click on any event log row to expand/collapse
- Arrow indicator rotates when expanded
- Full JSON payload shown indented in pre block
- Max height with scroll for large payloads
* style(debug-server): format long line in fullPayload function
* test(debug-server): add to E2E tests and screenshot specs
* chore: regenerate package-lock.json for cross-platform compatibility
* update dep
* docs: standardize UI terminology to use "view" consistently
Replaces "widget" and "Guest UI" terminology with "view" across
the codebase as decided in the community survey.
This change updates:
- Specification document
- SDK source code and JSDoc comments
- Example servers and documentation
- Plugin documentation and skills
Closes#71
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Implement the conventional MCP pattern for transport backward compatibility:
try `StreamableHTTPClientTransport` first (modern), then fall back to
`SSEClientTransport` (deprecated but needed for older servers).
This follows the approach documented in the MCP TypeScript SDK's
`streamableHttpWithSseFallbackClient.ts` example.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
- Add `.gitignore` files to all 19 examples (`node_modules/`, `dist/`)
- Replace custom `log` objects with standard `console` methods
- Add `ontoolcancelled` handler to all `basic-server-*` examples
- Add host styling integration (`applyDocumentTheme`, `applyHostFonts`,
`applyHostStyleVariables`) to non-React `basic-server-*` examples
- Add section headers for better code organization in feature examples
- Update READMEs with Build System section explaining single-file
bundling
These changes make examples more consistent and easier to adapt.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* basic-host: filter non-ui tools
* basic-host: filter app-only tools, prioritize UI tools
- Filter out tools with visibility: ['app'] from host tool list
- Sort tools to show UI-enabled tools first, then alphabetically
- Add local isToolVisibleToModel helper in basic-host
* chore: release 0.4.0
* chore: add new examples to npm publish workflow
Add map-server, shadertoy-server, and transcript-server to the
publish-examples matrix.
* chore: remove tamper-detection.ts (not meant to be submitted)
Follow-up to PR #234. This file was accidentally included.
* revert to srcdoc
Follow-up to PR #234 per domfarolino's review feedback.
* regen
* regen
* refactor(basic-host): use SDK types for ModelContext and AppMessage
- Import McpUiUpdateModelContextRequest and McpUiMessageRequest from SDK
- Replace custom ModelContext with McpUiUpdateModelContextRequest['params']
- Replace custom AppMessage with McpUiMessageRequest['params']
- Pass full message params instead of extracting text
- Format messages by extracting text from content blocks in display
* feat(basic-host): handle non-text content blocks in display
- Add formatContentBlock helper for text, image, audio, resource types
- Show placeholders like <image: image/png> for non-text content
- Apply to both messages and model context display
* test: update shadertoy screenshot
* test: update screenshots from CI (linux x64)
* fix: Move CSP to HTTP headers + add worker-src, frameDomains, baseUriDomains, permissions
Security improvements:
- CSP is now set via HTTP headers in serve.ts instead of meta tags
(meta tag CSP can be tampered with by same-origin content)
- CSP passed as query param to sandbox.html for header-based enforcement
New CSP/permissions features (borrowed from PR #158):
- frameDomains: control frame-src directive for nested iframes
- baseUriDomains: control base-uri directive
- permissions: camera, microphone, geolocation via iframe allow attribute
WebGL fix:
- Use document.write() instead of srcdoc for inner iframe content
(srcdoc creates opaque origin that breaks WebGL canvas updates)
- Add worker-src directive with blob: support (critical for WebGL apps
like CesiumJS/Three.js that use workers for tile decoding, terrain
processing, image processing)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* refactor: Remove permissions support (defer to PR #158)
Keep this PR focused on CSP security fixes only.
Permissions (camera, microphone, geolocation) will be
handled in #158.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* cleanup McpUiResourceCsp type usage / duplicate defs
* fix: guard against CSP injection in domain parameters
Validate CSP domain entries to reject characters that could:
- Break out of CSP directives (semicolons, newlines)
- Inject CSP keywords like 'unsafe-eval' (quotes)
- Inject multiple sources in one entry (spaces)
This prevents injection attacks where malicious domains could
override the security policy.
---------
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
* fix(app): add source validation to default PostMessageTransport
App.connect() now passes window.parent as both eventTarget and eventSource,
enabling source validation by default. This ensures apps only accept
messages from their parent window, preventing potential cross-app
message spoofing attacks.
Previously, the default transport only specified the target but not the
source for validation, meaning apps would accept messages from ANY window.
* fix(sandbox): add origin validation for host messages
The sandbox proxy now validates that messages from the parent window
come from the expected host origin (derived from document.referrer).
This prevents malicious pages from sending spoofed messages to the sandbox.
Changes:
- Extract EXPECTED_HOST_ORIGIN from document.referrer
- Validate event.origin against expected origin for parent messages
- Use specific origin instead of '*' when sending to parent
- Reject and log messages from unexpected origins
This addresses the TODO comment that was previously in the code.
* validate messages from app come from same origin as sandbox proxy
* fix(basic-host): be resilient to individual server connection failures
Use Promise.allSettled instead of Promise.all when connecting to
servers, so that a single server failure doesn't crash the entire UI.
Failed connections are logged as warnings but the UI continues with
the servers that connected successfully.
Also fixes video-resource-server missing server-utils.ts.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
---------
Co-authored-by: Claude <noreply@anthropic.com>
* Update `package.json`
* Add TypeScript type checking to example build scripts
Add `tsc --noEmit &&` before `vite build` in all example `package.json`
files to catch type errors during builds. Previously, type errors
in `server.ts` files were not detected because Vite/Bun transpile
without type checking.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Make `_meta` optional in `McpUiAppResourceConfig`
The `_meta` and `ui` properties were required, causing TypeScript errors
when calling `registerAppResource()` without providing metadata.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Fix Zod type compatibility in `registerAppTool()`
Use `ZodRawShapeCompat | AnySchema` from SDK's `zod-compat` module
instead of raw `ZodRawShape` to resolve type errors when examples
pass `ZodObject` schemas to `registerAppTool()`.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Remove unused imports in example apps
- `basic-server-react`: Remove unused `McpUiResourceTeardownResult`
- `customer-segmentation-server`: Remove unused `PostMessageTransport`
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* Fix CI git install test for fork PRs
Use `github.event.pull_request.head.repo.full_name` to correctly
reference the fork repository when testing git installs from PRs.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
---------
Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>
* feat: make MCP SDK a peer dependency
- Move @modelcontextprotocol/sdk from dependencies to peerDependencies (^1.20.0)
- Add to devDependencies for local development (^1.24.3)
- Externalize SDK from all build entry points (app, app-bridge, react, server)
Benefits:
- Consumers control their SDK version
- Deduplication when consumer already has SDK
- Follows pattern of react/zod peer deps
* fix: require SDK ^1.24.0 for Zod 4 compatibility
Earlier SDK versions have Zod type incompatibilities that cause build errors.
* chore: update examples to SDK ^1.24.0 to match peer dep
