Build an Executor app

An app is TypeScript source with a default defineApp export from apps. Its package.json declares the exact apps version it uses, which framework.release returns. App authors use ordinary async functions; Effect stays inside the framework. An app's installed name is separate from its source definition.

Choose how to work

With a shell, prefer the local CLI path in deploy.md: keep the source in a directory, edit it with your file tools, and deploy with executor apps (npm executor@beta). The pinned apps package from npm supplies types and framework-reference.json, so writing code needs no MCP. Use MCP only to connect accounts and call the deployed app. Without a shell, build through execute; source then travels as data inside tool calls.

Read only the topics needed

For an existing app, read its current source and the reference for the part being changed. Tools generated from an MCP server, OpenAPI definition or GraphQL schema are a starting point; when one is missing or wrong, write your own tool beside it with the same account (integrations.md).

Load files through the MCP skills tool using the returned app slug, version and content revision, for example { app: "executor", name: "app-authoring", file: "ui.md", version, revision }. The management app's skills.list and skills.read read with the caller's linked accounts.

Discover exact contracts

Use tools.search inside execute to find callable app tools. It returns their exact paths, one-line descriptions and input types. Read a tool's output type and whole description with tools.search.describe({ paths }). Discover framework.search and framework.describe on this Executor app to inspect library functions and methods. These queries return generated signatures, related types, examples and documentation links. Framework functions are imports or methods used in app source, not MCP tools.

Call framework.search({ query: { text } }), then framework.describe({ query: { symbol, version, digest } }) with a symbol it returns. Start with apps.defineApp, apps.query, DatabaseTable.insert, or apps/react.useAppQuery. Both take their input under query, unlike tools.search({ query: "send email" }), whose query is a plain string. The reference identifies its exact framework version and content digest. Keep that identity on subsequent reads. Do not assume a host reference describes a different pinned apps package; that package ships framework-reference.json.

Hosted management calls require an explicit organization. Discover and call context.get({}) first. Local management calls have no organization parameter. Read each discovered signature; do not guess route arguments.

Build and verify

Use output schemas for typed results. Import server declarations as types only in browser code. Put shared schemas in a separate file. Read the relevant reference for return shapes and behavior instead of deploying probe apps.

Deploying compiles TypeScript but does not replace a type check or prove that the page renders. Verify the requested behavior on the authenticated app page. If browser access is unavailable, report exactly what remains unverified. Never put credentials in source, browser code or tool arguments. Use the secure account connection flow described in accounts.md.

Send feedback

Before your final reply, send feedback with the Executor app's feedback.submit tool if anything about Executor slowed you down, confused you or was missing, or if something worked especially well. Skip it if there is nothing worth reporting. The executor skill's feedback.md says what to write.