--- title: "Dex App Builder" description: "Dex App Builder is the primary skill for creating a Dex application or" canonical_url: "https://docs.superdurable.io/build-with-ai/dex-developer-skill/dex-app-builder/" source: "docs/content/build-with-ai/dex-developer-skill/dex-app-builder.mdx" locale: "en" --- # Dex App Builder Dex App Builder is the **primary skill** for creating a Dex application or process product. It covers the whole path: working out the business process, choosing the UI, building the Go backend, testing locally, and handing off the result. ## Install and use Choose your current host. On one host, use either the Plugin or standalone Skills, not both. ### Codex Desktop #### Plugin (recommended) ##### Install This path does not require a separate Codex CLI installation. 1. Open the plugin browser, open the add menu, and select Add a marketplace. 2. Use the repository below as Source, main as Git ref, and leave Sparse paths empty. ```text https://github.com/superdurable/dex-skills ``` 3. Add the marketplace, open Super Durable, select Dex, and install it. 4. Open a repository or empty project, then start a new task. ##### Use Type @, select Dex from the picker, then enter the request. Plain @Dex text does not create a Plugin binding. ```text @Dex Design and build an event-registration application. ``` ##### Update Find Super Durable in the plugin browser marketplace manager and select Upgrade. Restart the desktop app and start a new task. #### Standalone Skills Do not also install the Plugin when using this path. Install all three Skills together. ##### Install ```bash npx skills add superdurable/dex-skills --skill '*' --agent codex --global ``` ##### Use ```text $dex-app-builder Design and build an event-registration application. ``` ##### Update ```bash npx skills update dex-app-builder dex-sdk dex-connector-contributor --global ``` If the installed skills CLI does not support update, rerun the installation command above. ### Codex CLI #### Plugin (recommended) ##### Install First confirm that Codex CLI is available on PATH, then add the marketplace and Plugin. ```bash codex --version codex plugin marketplace add superdurable/dex-skills codex plugin add superdurable-dex@superdurable ``` ##### Use Start a new interactive Codex session, type @, and select Dex from the picker. Plain @Dex text in the initial codex prompt or codex exec is not a structured Plugin binding. ```text @Dex Design and build an event-registration application. ``` ##### Update ```bash codex plugin marketplace upgrade superdurable codex ``` Open /plugins in the new session and confirm that Dex is enabled. #### Standalone Skills Do not also install the Plugin when using this path. Install all three Skills together. ##### Install ```bash npx skills add superdurable/dex-skills --skill '*' --agent codex --global ``` ##### Use ```text $dex-app-builder Design and build an event-registration application. ``` ##### Update ```bash npx skills update dex-app-builder dex-sdk dex-connector-contributor --global ``` If the installed skills CLI does not support update, rerun the installation command above. Use the standalone Skill path for deterministic non-interactive invocation. ### Claude Desktop #### Plugin ##### Install 1. Open Customize and select the Plugins tab. 2. Select Add → Add marketplace → Add from a repository. 3. Enter the repository below, then open the Super Durable marketplace and install Dex. ```text https://github.com/superdurable/dex-skills ``` ##### Use Use a natural-language request or the / picker. ```text /superdurable-dex:dex-app-builder Design and build an event-registration application. ``` ##### Update Claude does not document a per-user upgrade command. For an organization-managed marketplace, an owner uses Organization settings → Plugins & skills → Marketplaces → Update. #### Standalone Skills Dex does not distribute standalone ZIP Skills for Claude web or desktop. Use the Plugin path. ### Claude Code CLI #### Plugin (recommended) ##### Install Run these commands in a shell. You can also use their /plugin forms inside an interactive Claude Code session. ```bash claude plugin marketplace add superdurable/dex-skills claude plugin install superdurable-dex@superdurable ``` Start a new Claude Code session after installation. Claude Code 2.1.273 or later can also sync the desktop Plugin for the same account. ##### Use ```text /superdurable-dex:dex-app-builder Design and build an event-registration application. ``` ##### Update ```bash claude plugin update superdurable-dex@superdurable ``` You can instead use /plugin marketplace update superdurable in an interactive session. Start a new session afterward. #### Standalone Skills Do not also install the Plugin when using this path. Install all three Skills together. ##### Install ```bash npx skills add superdurable/dex-skills --skill '*' --agent claude-code --global ``` ##### Use ```text /dex-app-builder Design and build an event-registration application. ``` ##### Update ```bash npx skills update dex-app-builder dex-sdk dex-connector-contributor --global ``` If the installed skills CLI does not support update, rerun the installation command above. ### Cursor #### Plugin (recommended) ##### Install 1. Open a project in Cursor Desktop, then open Customize in the sidebar. 2. Select Plugins → Add → From GitHub Repository and enter the repository below. ```text github.com/superdurable/dex-skills ``` 3. Open Dex, select Install, and choose a user or project scope. A user-scope desktop installation is also available to Cursor CLI. Alternatively, start cursor-agent, enter /plugin, and install Dex from the Marketplace tab. ##### Use ```text /dex-app-builder Design and build an event-registration application. ``` ##### Update For a GitHub-imported team marketplace, an administrator selects Refresh or enables Auto Refresh, then users reload the Cursor window. #### Standalone Skills Do not also install the Plugin when using this path. Install all three Skills together. ##### Install ```bash npx skills add superdurable/dex-skills --skill '*' --agent cursor --global ``` ##### Use ```text /dex-app-builder Design and build an event-registration application. ``` ##### Update ```bash npx skills update dex-app-builder dex-sdk dex-connector-contributor --global ``` If the installed skills CLI does not support update, rerun the installation command above. Cursor uses the same short slash command for Plugin and standalone installs; only the installation source differs. ### Other clients #### Plugin Dex does not document one universal marketplace Plugin flow for unlisted hosts. #### Standalone Skills Use standalone Skills with other Agent Skills clients. ##### Install Select a detected compatible agent interactively, or pass the host agent id explicitly. ```bash npx skills add superdurable/dex-skills --skill '*' --global npx skills add superdurable/dex-skills --skill '*' --agent --global ``` ##### Use Use the host Skill picker, invocation prefix, or a matching natural-language request. ```text Design and build an event-registration application. ``` ##### Update ```bash npx skills update dex-app-builder dex-sdk dex-connector-contributor --global ``` ## When to use it Use App Builder when the request includes any of these: - discovering or refining a business process; - defining roles, permissions, approvals, waits, retries, and recovery; - deciding whether Dex Web is enough or a custom UI is needed; - building a new Dex application from the supported template; - using released Connectors, or finding a Connector that is missing; - building and testing one complete feature, from UI to backend. For a narrow SDK debugging task or a standalone official Connector contribution, invoke [Dex SDK](https://docs.superdurable.io/build-with-ai/dex-developer-skill/dex-sdk.md) or [Dex Connector Contributor](https://docs.superdurable.io/build-with-ai/dex-developer-skill/dex-connector-contributor.md) directly instead. ## Before implementation App Builder first checks that the coding-agent host gives it a writable repository or project, file-editing tools, and command execution. Without them, App Builder can still work out the process, design the architecture, and write a plan for implementation. It cannot create files, run tests, build artifacts, or deploy an application. ## Workflow ### 1. Confirm the business process The skill starts by talking with you, not by writing code. It works out: - who maintains, manages, operates, approves, and takes part in the process; - what each role can do, and the stable permission each human action requires; - triggers, inputs, outputs, deadlines, waits, retries, recovery, audit, and which data is sensitive; - the external systems, and the released Connector capabilities they need; - whether an existing host application signs users in and maps their roles to permissions it trusts. This step ends with a table of roles, operations, and permissions, a proposed lifecycle, a UI decision, and a table of the Connector capabilities needed. The skill settles every open question that matters with you before any code is written. ### 2. Choose the application surface App Builder picks one of two ways to manage the process: | Mode | When it fits | What gets built | | ------------- | ------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------- | | **Dex Web** | Runs, Work Queue, search, fields, and Actions cover what the users need. | Dex Web is the process UI. The application adds only a small shell with no business screens, plus the endpoints that external systems call. | | **Custom UI** | The product needs business screens or interactions that Dex Web does not offer. | The skill builds a React and TypeScript prototype on mock data. You try it and approve it before it is connected to the real backend. | Dex Web is the default. A Hello World page left over from the template, or a generated API client, is not by itself a reason to build a custom UI. ### 3. Design and implement the Flow The backend uses the supported application template and the Dex Go SDK. App Builder loads [Dex SDK](https://docs.superdurable.io/build-with-ai/dex-developer-skill/dex-sdk.md) for the general SDK rules, then adds stricter rules of its own: - write the application backend in Go; - target strict Dex Web and Flow Definition Graph 2.0 rendering; - call external providers only from **Execute**; - keep provider calls and Dex changes out of **WaitFor**; - model each human operation as a typed Action with an explicit permission; - keep credentials inside Connectors or the runtime environment, not in application code; - use released Connector capabilities instead of adding provider clients to the application. Before it writes code, the skill states the Flow's identity, typed input and output, Steps, transitions, Attributes, Channels, RPCs, Timers, retries, recovery, and Connector boundaries. ### 4. Verify and hand off While it works, the skill runs the tests related to each change. At the end, it runs the template's full check. This covers the chosen UI mode, generated code, the production build, behavior against a real Dex Server, recovery paths, and the FDG 2.0 analysis. The handoff lists the product decisions you confirmed, what was built, the exact test results, the status of any Connector release or contribution, and known limitations. The work ends in a clean Git commit. ## How Connector gaps are handled Before it writes integration code, App Builder checks what the released Connectors can do. An official Connector may be missing, or an operation, Trigger, or configuration UI unit the application needs may be missing or broken. App Builder then loads [Dex Connector Contributor](https://docs.superdurable.io/build-with-ai/dex-developer-skill/dex-connector-contributor.md). While the contribution is in review, the application can test against a local copy of the Connector module. The application is not ready for production until that Connector is released with an exact version. The skill never commits a branch, commit SHA, pseudo-version, or local replacement as a production dependency. ## Expected result When App Builder finishes, you have: - a confirmed process and permission model; - a clear choice between Dex Web and a custom UI; - a Go Dex application built on the supported template; - test evidence from local runs and a real Dex Server; - a list of Connector releases that still block production, if any; - a repository ready for review. Return to [Dex Skills overview and installation](https://docs.superdurable.io/build-with-ai/dex-developer-skill.md).