- name
- mcp-apps-builder
- description
- Build, modify, debug, migrate, review, or verify TypeScript MCP servers and MCP Apps with mcp-use. Use for tools, resources, prompts, middleware, Views, authentication, Skills over MCP, scaffolding, and advanced features.
Build with mcp-use
Treat the installed mcp-use package, its exported types, generated declarations, and the project's existing code as the source of truth. Inspect the installed version before choosing APIs or changing code.
Workflow
- Inspect
package.json, the server entry, exported tool refs,mcp-env.d.ts,views/,skills/, and the installedmcp-useversion. - Scaffold a new stable project with
create-mcp-use-app@latestand the appropriate template. Match the package version or dist-tag when working on beta, canary, or an existing versioned project. - Read only the references needed for the task:
- Server for tools, resources, prompts, MCP middleware, request context, and result envelopes.
- Views for interactive MCP Apps, React hooks, model context, host capabilities, assets, CSP, and endpoint/UI domain handling.
- Authentication for OAuth providers, verified identity, scopes, permissions, and authorization.
- Skills over MCP when a server should ship reusable workflows alongside its tools.
- Advanced features for OpenAPI, proxying, notifications, subscriptions, and elicitation.
- Migration only when retired or compatibility-only imports, helpers, registration shapes, UI patterns, or session assumptions are present.
- Verification before reporting implementation work complete.
- Implement against installed types. Prefer the framework's current conventions over copied examples or historical changelogs.
- Validate the smallest real lifecycle that proves the changed behavior, then expand checks in proportion to risk.
Core invariants
- Import server APIs from
mcp-use, React APIs frommcp-use/react, and OAuth provider adapters from theirmcp-use/oauth/*subpaths. - Define tool arguments with
inputSchema. AddoutputSchemafor structured results and every View-bound tool. - Return raw MCP result envelopes. A successful schema-backed tool must include matching
structuredContent; an expected failure may returnisError: truewith model-readablecontent. - Put each View at
views/<name>/view.tsxand bind it withview: { name: "<name>" }. - Export every statically declared tool ref consumed by a View. Default-export the server entry used by
mcp-use dev,build, andstart. - Keep identity and mutable workflow state request-scoped or in an external store. Treat client-reported metadata as unverified.
- Consider Skills over MCP when a server exposes a repeatable, multi-step workflow that would otherwise inflate tool descriptions.
Guardrails
- Do not invent exports, configuration fields, or callback shapes. Confirm uncertain details in installed declarations or source.
- Do not preserve APIs that are absent from the installed version merely because they appear in an existing project.
- Do not return a plain domain object from a tool callback.
- Do not bind a View without a matching
outputSchemaandstructuredContentresult. - Do not use module globals for cross-request identity, elicitation continuity, or durable business state.
- Do not claim success from a source build alone when types, package exports, authentication, or interactive behavior changed.
- Do not deploy or mutate external systems unless the user explicitly requests it.