Projen Project Manager

An expert assistant for working with projen-managed projects. This skill helps you execute tasks, modify configuration, manage dependencies, and follow best practices while respecting projen's workflow.

What This Skill Does

This skill provides guidance for working with projects managed by [projen](https://github.com/projen/projen), a project configuration management tool. It ensures you follow projen's conventions: running tasks through projen, modifying configuration in `.projenrc` files instead of generated files, and maintaining proper workflow.

Instructions

Task Execution Guidelines

1. **Always use projen for task execution**

- Run tasks using `node ./projen.js <task-name>` instead of npm, yarn, or other package managers

- Example: `node ./projen.js build` not `npm run build`

2. **Check available tasks first**

- Read `.projen/tasks.json` to see all available tasks, their descriptions, and steps

- Common tasks:

- `node ./projen.js` - Synthesize project configuration files

- `node ./projen.js build` - Build project and run tests

- `node ./projen.js test` - Run tests only

- `node ./projen.js compile` - Compile source code only

- `node ./projen.js eslint` - Run linter

3. **When developing projen itself**

- Avoid running full builds (they're slow)

- Run specific tests: `node ./projen.js test test/path-to-test.test.ts`

- Always run linter: `node ./projen.js eslint` frequently

File Modification Rules

1. **NEVER edit generated files directly**

- Files with comments like "~~ Generated by projen. To modify..." are off-limits

- These files will be overwritten when projen regenerates

2. **Always modify configuration in .projenrc**

- Look for `.projenrc.ts`, `.projenrc.py`, or `.projenrc.json`

- Make changes there, then run `node ./projen.js` to regenerate

3. **Check .projenrc before suggesting changes**

- Before recommending changes to `package.json`, `tsconfig.json`, or other config files

- Verify if they're managed by projen

- If so, suggest changes to `.projenrc` instead

Dependency Management

1. **Add dependencies through projen configuration**

- Don't manually edit `package.json`

- Don't run `npm install` or `yarn add` directly

2. **Use projen's dependency methods**

- `addDeps()` for runtime dependencies

- `addDevDeps()` for development dependencies

- `addPeerDeps()` for peer dependencies

- Add these to your `.projenrc` file

Standard Workflow

Follow this workflow for all changes:

1. Make changes to `.projenrc` configuration file

2. Run `node ./projen.js` to synthesize and update generated files

3. Review the changes to generated files

4. Run `node ./projen.js build` to ensure everything works

5. Commit both `.projenrc` and the generated files together

Task Completion Criteria

A task is NOT complete until:

Best Practices

1. **Always run build after changes**

- After modifying source or test files

- Run `node ./projen.js build` to verify everything compiles and passes tests

2. **Be efficient when developing projen**

- Run specific tests instead of the full suite

- Use linter frequently to catch issues early

3. **Understand the project structure**

- Check `.projen/tasks.json` when unsure about available commands

- Review `.projenrc` to understand project configuration

Examples

Adding a Dependency

```typescript

// In .projenrc.ts

project.addDeps('lodash');

project.addDevDeps('@types/lodash');

```

Then run: `node ./projen.js`

Running Tests

```bash

All tests

node ./projen.js test

Specific test file

node ./projen.js test test/my-feature.test.ts

```

Making Configuration Changes

```bash

1. Edit .projenrc.ts

2. Regenerate files

node ./projen.js

3. Build and test

node ./projen.js build

```

Resources

Important Constraints