Files
calendar/agents/rules
Keith WilliamsGitHubDevin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
d4ea931bf8 feat(agents): add modular engineering rules from 2026 standards (#26847)
* feat(agents): add modular engineering rules from 2026 standards

Add a rules directory with individual rule files derived from the
Cal.com Engineering in 2026 and Beyond blog post. Rules are organized
by section (architecture, quality, data, api, performance, testing,
patterns, culture) following the Vercel agent-skills structure.

Includes:
- _sections.md defining rule categories and impact levels
- _template.md for creating new rules
- 14 individual rule files covering key engineering standards
- README documenting the rules structure and usage

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* feat(agents): consolidate DI and Repository+DTO docs into rules

- Move di-pattern.md content to rules/patterns-di-pattern.md
- Extract Repository + DTO section from knowledge-base.md into:
  - rules/data-repository-methods.md (method naming conventions)
  - rules/data-dto-boundaries.md (DTO location and naming)
- Update knowledge-base.md to reference the new rule files
- Delete old di-pattern.md file

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* chore(agents): remove stub reference sections from knowledge-base.md

The rules directory is self-contained with its own README, so these
redirect sections are unnecessary clutter.

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

* refactor(agents): combine DI pattern rules into single file

Merged patterns-di-pattern.md into patterns-dependency-injection.md
to eliminate overlap and create one comprehensive DI guide.

Co-Authored-By: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>

---------

Co-authored-by: Devin AI <158243242+devin-ai-integration[bot]@users.noreply.github.com>
2026-01-16 10:57:28 +01:00
..

Cal.com Engineering Rules

This directory contains modular, machine-readable engineering rules derived from Cal.com's Engineering Standards for 2026 and Beyond.

Structure

Rules are organized by section prefix, as defined in _sections.md:

Prefix Section Impact
architecture- Architecture CRITICAL
quality- Code Quality CRITICAL
data- Data Layer HIGH
api- API Design HIGH
performance- Performance HIGH
testing- Testing MEDIUM-HIGH
patterns- Design Patterns MEDIUM
culture- Team Culture MEDIUM

Files

  • _sections.md - Defines all sections, their ordering, and impact levels
  • _template.md - Template for creating new rules
  • {section}-{rule-name}.md - Individual rule files

Rule Format

Each rule file follows a consistent format with YAML frontmatter:

---
title: Rule Title Here
impact: CRITICAL | HIGH | MEDIUM | LOW
impactDescription: Optional description (e.g., "20-50% improvement")
tags: tag1, tag2, tag3
---

## Rule Title Here

**Impact: LEVEL (optional description)**

Brief explanation of the rule and why it matters.

**Incorrect (description):**
\`\`\`typescript
// Bad code example
\`\`\`

**Correct (description):**
\`\`\`typescript
// Good code example
\`\`\`

Reference: [Link](url)

Adding New Rules

  1. Copy _template.md to a new file with the appropriate section prefix
  2. Fill in the frontmatter (title, impact, tags)
  3. Write a clear explanation of the rule
  4. Provide incorrect and correct code examples
  5. Add a reference link if applicable

Usage

These rules are designed to be:

  • Human-readable: Engineers can browse and learn from them
  • Machine-readable: AI agents can parse and apply them
  • Modular: Individual rules can be updated without affecting others
  • Versionable: Changes are tracked in git history

Core Principles

From the blog post, our engineering philosophy is:

We are building infrastructure that must almost never fail. To achieve this, we move fast while shipping amazing quality software with no shortcuts or compromises.

The rules in this directory encode the specific practices that enable this philosophy.