extension-creator

name	extension-creator
description	Create AiderDesk extensions by setting up extension files, defining metadata, implementing Extension interface methods, and updating documentation. Use when building a new extension, creating extension commands, tools, or event handlers.

Extension Creator

Create AiderDesk extensions that extend functionality through events, commands, tools, agents, and modes.

When to Use

Use this skill when:

• Building a new AiderDesk extension
• Creating extension commands, tools, or event handlers
• Implementing the Extension interface
• Setting up extension metadata and documentation

Do not use when:

• Simply activating an existing extension
• Making general code changes unrelated to extensions
• Running tests or builds

Rules

Rule: Choose installation target first

When: Starting extension creation

Then: Ask the user where to install the extension

If: Working inside the AiderDesk project (the current project is the aider-desk repository)

Then: Offer three options:

1. Current Project — Install to .aider-desk/extensions/ in the current project (project-scoped)
2. Global — Install to ~/.aider-desk/extensions/ (available in all projects)
3. In-Repo — Create inside packages/extensions/extensions/ (ships with AiderDesk app)

If: Working outside the AiderDesk project

Then: Offer two options:

1. Current Project — Install to .aider-desk/extensions/ in the current project (project-scoped)
2. Global — Install to ~/.aider-desk/extensions/ (available in all projects)

Must: Wait for user's choice before proceeding. The chosen target determines the entire workflow.

Reference: references/install-targets.md for full details on each target.

Rule: Follow the correct flow for the chosen target

When: User has chosen an installation target

If: Target is Current Project or Global

Then: Follow the Project / Global Flow:

1. Determine extension type (single-file or folder)
2. Create extension file(s) in the target directory (.aider-desk/extensions/ or ~/.aider-desk/extensions/)
3. Implement Extension interface methods
4. Export metadata and default class
5. Verify the extension loads (auto-discovered, no registry needed)

If: Target is In-Repo

Then: Follow the In-Repo Flow:

1. Determine extension type (single-file or folder)
2. Create extension file(s) in packages/extensions/extensions/
3. Implement Extension interface methods
4. Export metadata and default class
5. Register in packages/extensions/extensions.json
6. Document in docs-site/docs/extensions/examples.md
7. Install npm dependencies if folder extension
8. Verify with type checking

Rule: Determine extension type

When: Creating extension files (after target is chosen)

Then: Check if extension needs npm dependencies or multiple files

If: Extension needs dependencies or multiple files

Then: Create folder extension

If: Extension is simple with no dependencies

Then: Create single-file extension

Rule: Implement Extension interface

When: Creating extension file

Then: Implement required methods from Extension interface

Must: Define static metadata property on the class with name, version, description, author, capabilities

Must: Export class as default (e.g., export default class MyExtension implements Extension)

Never: Use @/ imports in extension files

Rule: Add UI components when needed

When: Extension needs to display UI elements in task page placements

Then: Implement getUIComponents() method

Must: Return array of UIComponentDefinition objects with id, placement, jsx

Must: Define components as JSX strings or load from .jsx files

If: Component needs data, set loadData: true and implement getUIExtensionData()

If: Component triggers actions, implement executeUIExtensionAction()

Rule: Add config component for extension settings

When: Extension needs user-configurable settings (shown in gear icon dialog)

Then: Implement three methods: getConfigComponent(), getConfigData(), saveConfigData()

Must: Return JSX string from getConfigComponent() — use external .jsx file for components > 20 lines

Must: Load/merge defaults in getConfigData(), persist merged data in saveConfigData()

Must: Store config file in extension directory via join(__dirname, 'config.json')

Must: Use ui.* components (ui.Input, ui.Checkbox, etc.) instead of raw HTML elements

Should: Avoid inner state (useState/useEffect) for simple form fields — read directly from config prop, call updateConfig on change. Only use local state for derived values or transient UI state.

Never: Use 'extension-settings' placement — it was removed; use the dedicated config API instead

Rule: Update registry and docs (In-Repo only)

When: Target is In-Repo and extension file is created

Then: Add entry to packages/extensions/extensions.json

Must: Include id, name, description, file or folder path, type, capabilities

Must: Set hasDependencies: true for folder extensions

Then: Add entry to docs-site/docs/extensions/examples.md table

Must: Include extension name, description, capabilities, and type

When: Target is Project or Global

Then: Do NOT modify extensions.json or examples.md — these are only for built-in extensions

Rule: Use proper TypeScript config for folders

When: Creating folder extension

Then: Include tsconfig.json with module: ES2020+

Must: Include package.json with name, version, main, dependencies

Rule: Store config in extension directory

When: Extension needs persistent config

Then: Store config files in extension directory

Never: Store config outside extension directory

Process Overview

For Project / Global targets:

1. Ask user: Current Project or Global?
2. Determine extension type (single-file or folder)
3. Create extension file or directory structure in target dir
4. Implement Extension interface methods
5. Export metadata and default class
6. Verify extension loads (auto-discovered)

Between steps 3 and 5:

• If extension needs config storage, create config.ts (or use inline getConfigData/saveConfigData)
• If extension has a settings UI (config component), create ConfigComponent.jsx and implement the three config methods
• If extension needs logging, create logger.ts
• If extension needs constants, create constants.ts
• If extension has placement-based UI components, create .jsx files for components (recommended for components > 20 lines)

For In-Repo target:

1. Confirm user wants In-Repo (only available in aider-desk project)
2. Determine extension type (single-file or folder)
3. Create extension file or directory structure in packages/extensions/extensions/
4. Implement Extension interface methods
5. Export metadata and default class
6. Register in packages/extensions/extensions.json
7. Document in docs-site/docs/extensions/examples.md
8. Run npm install in packages/extensions/ (folder extensions)
9. Verify with type checking

Between steps 3 and 5:

• Same optional files as Project/Global flow above

Preconditions

Before using this skill, verify:

• Installation target has been chosen by the user
• Extension purpose and required capabilities are clear
• Extension type (single-file or folder) is determined
• Extension interface and types are understood

If any precondition fails:

• Review packages/common/src/extensions.ts for types
• Check references/install-targets.md for target options
• Check references/event-types.md for event types
• Check references/command-definition.md for command structure

Postconditions

After completing this skill, verify:

• Extension implements Extension interface correctly
• Static metadata property on the class includes all required fields (name, version)
• Default export is the extension class
• No @/ imports used
• If In-Repo: extensions.json updated correctly
• If In-Repo: docs-site/docs/extensions/examples.md updated
• If In-Repo: Type checking passes
• Extension loads without errors
• Extension appears in extensions list
• Extension capabilities work as expected

Success metrics:

• Extension loads without errors
• Extension appears in extensions list
• Extension capabilities work as expected

Common Situations

Situation: Extension needs to handle events

Pattern:

• When: Extension needs to modify agent behavior
• Then: Implement event handler methods (onAgentStarted, onToolCalled, etc.)
• Return: Partial event object to modify behavior

Situation: Extension needs to register commands

Pattern:

• When: Extension provides slash commands
• Then: Implement getCommands() method
• Return: Array of CommandDefinition objects

Situation: Extension needs to add UI components

Pattern:

• When: Extension needs to display information in UI
• Then: Implement getUIComponents() method
• Return: Array of UIComponentDefinition objects
• Use: JSX strings or external .jsx files
• Load data: Implement getUIExtensionData() if component needs data
• Handle actions: Implement executeUIExtensionAction() for user interactions

Situation: Extension needs to log messages

Pattern:

• If: Debug/internal logging (developer diagnostics, not shown to users)
• Then: Use context.log(message, type) — logs to backend console only
• If: User-visible output (showing results, status, timing info in the chat)
• Then: Use context.getTaskContext()?.addLogMessage(level, message) — displays in task's chat UI
• When ambiguous: If the user says "log", "show", "display", or "report" something, default to addLogMessage (user-visible). Use context.log only for internal diagnostics.
• Note: context.log is always available; getTaskContext() returns null outside a task, so always use optional chaining (?.)

Situation: Extension needs config storage

Pattern:

• Check: Extension needs persistent settings
• If yes: Create config.ts with loadConfig and saveConfig functions
• Store: Config files in extension directory

Situation: Extension needs a settings UI (config component)

Pattern:

• When: Extension has user-configurable options that should appear in the Settings dialog
• Then: Implement getConfigComponent(), getConfigData(), saveConfigData() methods
• JSX: Return a .jsx file content via readFileSync(join(__dirname, './ConfigComponent.jsx'), 'utf-8')
• Props: Component receives { config, updateConfig, ui, icons, models, providers, ... }
• Flow: Dialog opens → loads data via getConfigData → renders JSX with props → user edits → Save calls saveConfigData
• Reference: config-components.md for full guide and examples

References

Target Selection

• install-targets.md - All three installation targets, when to use each, key differences

Flows

• project-global-flow.md - Step-by-step for Project and Global installations
• in-repo-flow.md - Step-by-step for In-Repo (packages/extensions/) installations

Technical Reference (all targets)

• packages/common/src/extensions.ts - Extension types and interfaces
• extension-interface.md - Full Extension interface, ExtensionContext, TaskContext, Metadata
• extension-types.md - Single-file vs folder extensions, examples, extensions.json format
• event-types.md - All event types and payloads
• command-definition.md - Command structure
• ui-components.md - UI component system, placements, and available components
• config-components.md - Config component API (settings UI), methods, JSX format, and patterns
• examples-gallery.md - Real extension examples

Assets

• templates/single-file.ts.template - Single-file template
• templates/folder-extension/ - Folder template (basic)
• templates/folder-extension-with-config/index.ts.template - Folder template with config component API
• templates/ui-component.ts.template - UI component inline template
• templates/ui-component-external.ts.template - UI component with external JSX
• templates/Component.jsx.template - Placement-based JSX component template
• templates/ConfigComponent.jsx.template - Config/settings JSX component template