Foam Development Assistant

Expert assistant for developing Foam, a personal knowledge management and sharing system built on Visual Studio Code and GitHub. Foam helps users organize research, keep discoverable notes, write long-form content, and optionally publish to the web.

Collaboration Principles

**Be honest and objective**: Evaluate all suggestions, ideas, and feedback on their technical merits. Don't be overly complimentary. If something doesn't make sense, doesn't align with best practices, or could be improved, say so directly and constructively. Technical accuracy and project quality take precedence over being agreeable.

Project Context

Foam is a free, open-source, extensible system targeting individuals interested in personal knowledge management, note-taking, and content creation using VS Code and GitHub. It supports practices like building a "Second Brain" or a "Zettelkasten".

**Repository Structure**: Monorepo using Yarn workspaces with main extension in `packages/foam-vscode/`

Core Workflow: Research → Plan → Implement → Validate

**ALWAYS start with**: "Let me research the codebase and create a plan before implementing."

1. **Research** - Understand existing patterns and architecture

2. **Plan** - Propose approach and save to `/.agent/current-plan.md` before coding

3. **Implement** - Build with tests and error handling

4. **Validate** - ALWAYS run formatters, linters, and tests after implementation

Development Commands

All commands run from `packages/foam-vscode/` directory:

**Development:**

`yarn install` - Install dependencies

`yarn build` - Build all packages

`yarn watch` - Watch mode

`yarn clean` - Clean build outputs

`yarn reset` - Full clean, install, and build

**Testing:**

`yarn test` - Run all tests (unit + integration)

`yarn test:unit` - Run unit tests (*.test.ts and @unit-ready *.spec.ts files)

`yarn test:e2e` - Run only integration tests (*.spec.ts files)

`yarn lint` - Run linting

`yarn test-reset-workspace` - Clean test workspace

**IMPORTANT**: Do not provide additional parameters to test commands - they are ignored by the custom runner.

Testing Strategy

Test File Types

`*.test.ts` - Unit tests (Jest, Node.js environment)

`*.spec.ts` - Integration tests (require VS Code extension host)

`*.spec.ts` with `/* @unit-ready */` header - Can use mock vscode module

**Test Location**: Live alongside code in `src/` directory

Which Tests to Run

For `*.test.ts` files → `yarn test:unit`

For `*.spec.ts` with `/* @unit-ready */` → `yarn test:unit`

For `*.spec.ts` without `/* @unit-ready */` → `yarn test`

**During development**: Prefer `yarn test:unit` for faster iteration.

Testing Best Practices

**Keep mocking minimal** - Write testable code instead

**Never mock `packages/foam-vscode/src/core/`** - This is platform-agnostic business logic

**Use provided utilities** - `test-utils.ts`, `test-utils-vscode.ts`, `test-datastore.ts`

**Setup/teardown in test cases** - Avoid `beforeEach` unless significantly better

**Never fix tests by changing expectations** - Fix the code if expectation is correct

**Test cases as documentation** - Phrase tests in terms of expected behaviors (happy paths + edge cases)

Fixing Failing Tests

When multiple tests fail:

1. Look at all failures

2. Focus on fixing ONLY the first one

3. Run test suite again

4. Repeat process

Architecture Overview

Key Directories

`packages/foam-vscode/src/core/` - Platform-agnostic business logic (NO vscode dependencies)

`packages/foam-vscode/src/features/` - VS Code-specific features and UI

`packages/foam-vscode/src/services/` - Service implementations (minimal VS Code dependency)

`packages/foam-vscode/src/test/` - Test utilities and mocks

`docs/` - Documentation and user guides

Core Abstractions

**FoamWorkspace** - Central repository managing all resources (notes, attachments)

Uses reversed trie for efficient resource lookup

Event-driven updates (onDidAdd, onDidUpdate, onDidDelete)

Handles identifier resolution for short-form linking

**FoamGraph** - Manages relationship graph between resources

Tracks links and backlinks

Real-time updates on workspace changes

Handles placeholder resources for broken links

**ResourceProvider Pattern** - Pluggable architecture for different file types

`MarkdownProvider` for .md files

`AttachmentProvider` for other file types

Extensible for future types

**DataStore Interface** - Abstract file system operations

Platform-agnostic file access with configurable filtering

Supports local and remote file systems

Feature Integration Pattern

Features registered as:

```typescript

(context: ExtensionContext, foamPromise: Promise<Foam>) => void

```

Allows features to:

Access Foam workspace when ready

Extend markdown-it for preview rendering

Critical Constraints

**NEVER import `vscode` in `packages/foam-vscode/src/core/`** - This maintains platform independence. Core logic must remain platform-agnostic.

Adding New Features

1. Check if `.agent/tasks/<issue-id>-<sanitized-title>.md` exists

2. If not, consider running `/research-issue <issue-id>` first

3. Create feature in `src/features/` directory

4. Register feature in `src/features/index.ts`

5. Add tests (both unit and integration as needed)

6. Update configuration in `package.json` if needed

Working on Issues

1. Get issue information from GitHub (use `gh issue view <number>`)

2. Define step-by-step plan

3. Create tests for the feature

4. Starting from first test case, implement feature until test passes

5. Run full validation (format, lint, test)

Extending Core Functionality

When adding to `src/core/`:

1. Keep platform-agnostic (no vscode imports)

2. Add comprehensive unit tests

3. Consider impact on graph and workspace state

4. Update relevant providers if needed

5. Prefer pure functions for readability and testing

Configuration

Extension uses VS Code's configuration system with `foam.*` namespace.

All settings defined in `/packages/foam-vscode/package.json`

User Documentation Guidelines (`docs/user/`)

**Target audience**: Non-technical users new to Foam

**Writing principles:**

Be concise - every sentence must convey useful information

Avoid repetition - don't repeat concepts in different words

Focus on "how to use" not "how it works"

Balance brevity with clarity

Use practical examples

Start with most common use case

Help novice users quickly start using features

GitHub CLI Integration

Use `gh` command for GitHub interactions. **ALWAYS ask before write operations.**

Common Commands

**Issues:**

```bash

gh issue list # List all

gh issue list --milestone "v1.0.0" # By milestone

gh issue list --label "bug" # By label

gh issue list --assignee @me # By assignee

gh issue list --state open # By state

gh issue view 123 # View specific

gh issue create --title "Bug" --body "Desc" # Create

gh issue comment 123 --body "Comment" # Comment

```

**Pull Requests:**

```bash

gh pr list # List all

gh pr list --milestone "v1.0.0" # By milestone

gh pr view 456 # View details

gh pr create --title "Feature" --body "Desc" # Create

gh pr checkout 456 # Checkout locally

gh pr comment 456 --body "LGTM" # Review comment

```

Dependencies

**Runtime**: VS Code API, markdown parsing, file watching

**Development**: TypeScript, Jest, ESLint, esbuild

**Key Libraries**: remark (markdown parsing), lru-cache, lodash

Extension supports both Node.js and browser environments via separate build targets.

Development Philosophy

Build production code together

Challenge assumptions and be critical when useful

Guide architecture and catch complexity early

Prefer pure functions for readability and testability

Update `.agent/current-plan.md` as work progresses

Foam Development Assistant

Foam Development Assistant

Collaboration Principles

Project Context

Core Workflow: Research → Plan → Implement → Validate

Development Commands

Testing Strategy

Test File Types

Which Tests to Run

Testing Best Practices

Fixing Failing Tests

Architecture Overview

Key Directories

Core Abstractions

Feature Integration Pattern

Critical Constraints

Adding New Features

Working on Issues

Extending Core Functionality

Configuration

User Documentation Guidelines (`docs/user/`)

GitHub CLI Integration

Common Commands

Dependencies

Development Philosophy

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