foundations

name	foundations
description	Establishes code quality, commit conventions, documentation standards, and security patterns. Use when writing or reviewing code, running checks, or setting up project standards. Covers naming, TDD, verification, and review workflows. Not for git workflow (use git-workflow), debugging (use debugging), or security audits (use security-compliance).

Code Standards

Engineering foundations for consistent, high-quality code.

Contents

• Critical Rules
• Verification
• Quick Reference
• Topics
• Available Scripts
• Naming Conventions
• Test Patterns

Critical Rules

Always

• Use type hints on all public functions
• Validate inputs at trust boundaries

Never

• Use bare except: clauses
• Log sensitive data or stack traces to users

Verification

After Editing Files

Format Checking:

• For Python files: If black is available, run black --check {files}
• For TypeScript/JavaScript files: If prettier is available, run prettier --check {files}
• For Ruby files: If standardrb is available, run standardrb --format quiet {files} or if rubocop is available, run rubocop --format quiet {files}
• Auto-fix commands:
  • Python: black {files}
  • TypeScript/JavaScript: prettier --write {files}
  • Ruby: standardrb --fix {files} or rubocop -a {files}

TDD Advisory:

• When editing implementation files (not test/spec files):
  • Check if corresponding test file exists
  • If no test found, consider Test-Driven Development:
    1. Write a failing test first
    2. Then implement the feature
    3. Run tests until green
  • Expected test file patterns:
    • Python: test_{name}.py or {name}_test.py
    • TypeScript/JavaScript: {name}.test.{ext} or {name}.spec.{ext}
    • Ruby: spec/{name}_spec.rb or test/{name}_test.rb
    • Go: {name}_test.go

Before Committing

• Run appropriate formatter on all changed files
• Run linter/type checker for the language
• Verify tests exist for new functionality
• Run test suite if tests were modified
• Ensure CHANGELOG.md is updated if needed

Workflow Notes

• Quick fixes with existing test coverage may skip TDD advisory
• Configuration and generated files don't need tests
• Editor format-on-save helps maintain compliance automatically

Quick Reference

Context	Python	TypeScript
Files	snake_case.py	PascalCase.tsx (components)
Functions	snake_case	camelCase
Classes	PascalCase	PascalCase
Constants	UPPER_SNAKE	UPPER_SNAKE
Tests	test_<unit>_<scenario>_<result>	describe/it blocks

Topics

Topic	Reference	Use When
Code Style	references/code-style.md	Writing Python/TypeScript code, naming variables
TDD	references/tdd.md	Writing tests first, red/green/refactor cycle
Verification	references/verification.md	Verifying work before claiming done
Code Review	references/code-review.md	Requesting or receiving code reviews
Review	references/review.md	Conducting structured code reviews
Permissions	references/permissions.md	Configuring tool allowlists, sandbox, agent permissions
Observability	references/observability.md	Instrumenting services, logging, metrics, tracing
Production Readiness	references/production-readiness.md	Validating services are ready for production

Available Scripts

Script	Usage	Description
scripts/check-python-style.py	check-python-style.py <dir>	Check Python style (type hints, docstrings)
scripts/check-test-naming.sh	check-test-naming.sh <dir>	Check test file/function naming

Naming Conventions

Context	Python	TypeScript
Files	snake_case.py	PascalCase.tsx (components)
Functions	snake_case	camelCase
Classes	PascalCase	PascalCase
Constants	UPPER_SNAKE	UPPER_SNAKE
Tests	test_<unit>_<scenario>_<result>	describe/it blocks

Artifact Names Never Cite Their Work Unit

Name an artifact for what it is, never for the work unit that produced it. The directory or Change that contains it already records that provenance, so repeating it in the filename inverts the reference and rots the moment the work closes: a work unit points at its artifacts, artifacts never point back.

Instead of	Write
u8-claude-smoke.mjs	smoke-claude-code-startup.mjs
report-spec-053-taxonomy-signoff.md	taxonomy-signoff.md
TASK-074-sidecar-audit-report.md	sidecar-audit.md

Provenance belongs in a front-matter field such as source:, where it can be read and updated, not in a name that has to be renamed to stay true.

Two look-alikes are correct and stay. A version is identity, not reference: claude-code-2.1.218-plugin-startup-smoke.json. A timestamp records when, not which work unit: 20260620-214448-skills-audit.md. And a numbered record living in the directory that owns it is that entity, so .agents/specs/SPEC-042-slug.md and docs/decisions/ADR-007-slug.md are its own name rather than a citation.

loaf check --hook artifact-names enforces this at commit time over tracked artifacts, grandfathering anything already final or archived.

Test Patterns

Scenario-based fixture naming:

• *_perfect - Complete, valid data (happy path)
• *_degraded - Partial data, quality issues
• *_chaos - Edge cases, malformed data

Coverage target: 70% minimum across all components.