* 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>
The term "external" is misleading for MCP Apps because developers
typically interpret it as "third-party." However, MCP App HTML runs in
a sandboxed iframe with no same-origin server, so *all* origins must be
declared—including where your own bundled JS/CSS is served from. Using
"network" instead avoids this confusion and aligns with the detailed
explanations in `patterns.md` and `spec.types.ts`.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Adds a new section to the patterns guide explaining how to configure
Content Security Policy and CORS for MCP Apps that make network requests:
- CSP via `_meta.ui.csp` controls browser-side permissions (`connectDomains`,
`resourceDomains`)
- CORS via `_meta.ui.domain` provides a stable origin for API servers to
allowlist
Includes a type-checked example showing `computeAppDomainForClaude()` helper
that hashes an MCP server URL to create a stable `*.claudemcpcontent.com`
subdomain. Also adds `@see` links to `McpUiResourceMeta` and `McpUiResourceCsp`
in `registerAppResource` JSDoc.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Move the inline example from the `getUiCapability()` JSDoc to
`index.examples.ts` for type checking, following the pattern used
by other examples in the codebase.
The example now uses the correct MCP SDK API:
- `server.server.oninitialized` callback for post-initialization hook
- `server.server.getClientCapabilities()` to retrieve capabilities
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* 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%)
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* 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
Migrate JSDoc and markdown documentation from `{@includeCode ./file#region}`
tags to inline code fences with `source="./file#region"` attributes.
Code examples are now visible directly in source files while remaining
type-checked via their `.examples.ts` source files.
Add `scripts/sync-snippets.ts` to extract code from `//#region` blocks
and sync it into labeled fences. Run with `npm run sync:snippets`.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
* 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>
Add explicit backtick-wrapped display text to all `{@link}` tags for
monospace rendering in TypeDoc output. This improves readability by:
- Using monospace font for code references (types, methods, functions)
- Stripping module prefixes from display text (e.g., `app!App.connect`
displays as `App.connect`)
Updated files across the SDK including `App`, `AppBridge`,
`PostMessageTransport`, React hooks, server helpers, types, and
documentation.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Document the `_meta.ui.visibility: ["app"]` feature in `docs/patterns.md`
by referencing the existing type-checked example from
`src/server/index.examples.ts#registerAppTool_toolVisibility`.
- Fix typo: `["apps"]` → `["app"]` (singular)
- Remove placeholder function from `docs/patterns.ts`
- Expand description to explain use cases
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Follow-up to the examples extraction: pass dependencies as function
parameters instead of using global stub declarations, rename region
names to match method names (e.g., `AppBridge_guestCapabilities_*` →
`AppBridge_getAppCapabilities_*`), and simplify examples using optional
chaining.
Also clarifies `RESOURCE_URI_META_KEY` documentation to indicate it's
for tool definition metadata (from `tools/list`), not tool result
metadata, and removes the redundant `setNotificationHandler` example
in favor of the simpler event setter approach.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Extract inline code examples from JSDoc comments into companion
`.examples.ts`/`.examples.tsx` files. Examples are now:
- Type-checked by wrapping them in functions
- Referenced via `{@includeCode ./file.examples.ts#regionName}` tags
- Organized using `//#region` and `//#endregion` markers
This keeps the main source files cleaner while ensuring examples
compile correctly. Updated TypeDoc config with `exampleTag: false`
to support title text on `@example` tags.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Adds a new skill (`plugins/mcp-apps/skills/migrate-oai-app/SKILL.md`)
that guides developers through migrating OpenAI Apps SDK applications
to the MCP Apps SDK. Includes API mapping tables, CSP configuration
guidance, and a "Before Finishing" checklist.
Also fixes the `registerAppResource()` JSDoc example in `src/server/index.ts`
to show CSP configuration in the correct location (on the content item,
not the resource config).
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Key improvements:
- Add `{@link}` cross-references throughout the codebase to make API
documentation navigable and help AI models understand relationships
- Use `{@link module!Export}` syntax for cross-module references
- Add backticks for inline code formatting (`ResizeObserver`, `App`, etc)
- Fix `PostMessageTransport` examples to show required two-argument form
- Clarify `onteardown` callback return type requirement
- Document React hooks cleanup behavior and Strict Mode considerations
- Add tool visibility example for `registerAppTool`
- Add CSP example for `registerAppResource`
- Fix notification direction documentation in `spec.types.ts`
TypeDoc config migrated from `typedoc.json` to `typedoc.config.mjs` to:
- Support custom `@description` block tag
- Add `intentionallyNotExported` for internal types
- Include `src/server/index.ts` entry point
Co-authored-by: Claude Opus 4.5 <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()`.
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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>
* docs: add tool visibility and restructure _meta.ui
- Restructure tool metadata: `_meta["ui/resourceUri"]` → `_meta.ui.resourceUri`
- Add `visibility` array field: ["model"], ["apps"], or ["model", "apps"]
- Default ["model"] preserves standard MCP behavior
- ["apps"] enables widget-only tools hidden from agent
- Add McpUiToolMeta interface for type safety
- Add Design Decision #4 explaining approach vs OpenAI's two-field model
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* address PR review comments
- Change default visibility to ["model", "apps"]
- Add deprecation notice for flat ui/resourceUri format
- Add McpUiToolMeta and McpUiToolVisibility to spec.types.ts
- Improve tools/list and tools/call behavior wording
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* chore: regenerate schemas for McpUiToolMeta types
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* feat: tool visibility and nested _meta.ui format
- Rename visibility "apps" → "app" in McpUiToolVisibility type
- Add _meta.ui.resourceUri nested format (deprecate flat format)
- Add getToolUiResourceUri() utility with backward compatibility
- Add visibility demo to system-monitor-server:
- get-system-stats: visibility ["model"] with resourceUri
- refresh-stats: visibility ["app"] (app-only polling)
- Update all example servers to use new _meta.ui format
- Add 11 unit tests for getToolUiResourceUri()
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* chore: regenerate schemas with updated dependencies
* feat: export McpUiToolMeta type and add type annotations
- Export McpUiToolMeta and McpUiToolVisibility types from types.ts
- Export corresponding Zod schemas (McpUiToolMetaSchema, McpUiToolVisibilitySchema)
- Add `as McpUiToolMeta` type annotations to all example servers
- Update docs/quickstart.md with proper typing
Ensures type safety for `_meta.ui` tool metadata across the codebase.
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Co-Authored-By: Claude <noreply@anthropic.com>
* feat: add server helpers and optional connect() transport
Add `src/server/` with convenience functions for registering MCP App tools
and resources:
- `registerAppTool(server, name, config, handler)`
- `registerAppResource(server, name, uri, config, callback)`
The `transport` parameter in `App.connect()` is now optional, defaulting to
`PostMessageTransport(window.parent)`.
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Co-Authored-By: Claude <noreply@anthropic.com>
* Update src/server/index.ts
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>
* feat: update McpUiAppToolConfig to support both _meta.ui and flat formats
* refactor: simplify server helper imports
* docs: add deprecation notice and improve resourceUri documentation
* feat: add backward compat normalization in registerAppTool
- If _meta.ui.resourceUri is set, also set legacy flat key
- If legacy flat key is set, also set _meta.ui.resourceUri
- Preserves existing visibility when merging
- Does not overwrite if both formats already set
* refactor: avoid mutating config arg in registerAppTool
* style: format with prettier
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Olivier Chafik <ochafik@anthropic.com>
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>
* feat: add server helpers and optional connect() transport
Add `src/server/` with convenience functions for registering MCP App tools
and resources:
- `registerAppTool(server, name, config, handler)`
- `registerAppResource(server, name, uri, config, callback)`
The `transport` parameter in `App.connect()` is now optional, defaulting to
`PostMessageTransport(window.parent)`.
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* Update src/server/index.ts
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>
* fix: refine server helper types
- Make RESOURCE_URI_META_KEY required in McpUiAppToolConfig (tools need a UI resource)
- Make _meta optional in McpUiAppResourceConfig (not all resources need custom metadata)
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
* refactor: simplify RESOURCE_URI_META_KEY re-export
* refactor: consolidate export statements
---------
Co-authored-by: Claude <noreply@anthropic.com>
Co-authored-by: Jonathan Hefner <jonathan@hefner.pro>
