Rules Generation

Rules Generation

Overview

Generate project-specific coding rules from a confirmed technology stack. This skill produces .claude/rules/ files that use YAML frontmatter paths for conditional loading, ensuring rules only appear in context when Claude works on matching files. Rules focus on code quality and best practices, consolidating related concerns into fewer, deeper files rather than many fragmented ones.

Target output: 4–5 consolidated rule files for a typical single-language, single-framework project.

Prerequisites

• A confirmed tech stack document (output of the tech-stack-confirmation skill), typically at docs/architecture/YYYY-MM-DD-<topic>-tech-stack.md
• ADR documents at docs/architecture/adr/
• An existing .claude/rules/ directory (global rules may already exist)

Scope Boundary

This skill covers coding rules generation ONLY:

• In scope: Reading tech stack artifacts, selecting applicable rule categories, generating consolidated rule files with paths scoping, deduplication with existing global rules, user review
• Out of scope: Technology selection (use tech-stack-confirmation), project scaffolding (use project-architecture-init), requirements gathering (use requirement-analysis)

If the user attempts to revisit technology selection decisions during this process, redirect: "That's a technology choice — the tech stack is already confirmed. To revise, re-run the tech-stack-confirmation skill."

The Process

Phase 1: Artifact Discovery — Locate All Inputs

Goal: Locate and read all tech stack artifacts produced by tech-stack-confirmation.

Execution rules:

1. Search for the confirmed tech stack document at docs/architecture/*-tech-stack.md
2. Search for ADR documents at docs/architecture/adr/ADR-*.md or docs/architecture/adr/*-ADR-*.md
3. Search for NFR summary if available in docs/architecture/ or inline in the tech stack document
4. Scan existing .claude/rules/ directory (both ~/.claude/rules/ and project-level) to identify global rules already in place
5. Read the project's CLAUDE.md file (if exists) for global instructions that affect rule generation

Phase 1 output: A summary listing:

• Tech stack document path and detected technologies (language, framework, database, testing, DevOps)
• ADR count and their titles
• Existing global rules already defined

Present this summary to the user for confirmation before proceeding.

Phase 2: Rule Selection — Determine Consolidated Rules

Goal: Based on the confirmed tech stack, determine which consolidated rule files to generate.

Method: Read references/rules-catalog.md for the consolidated rule category catalog and selection algorithm.

Execution rules:

1. Apply the selection algorithm from the catalog:
   • Always generate (max 1 always-loaded): git-conventions.md
   • Per language (1 file): Select the consolidated language best-practices file
   • Per framework (1 file): Select the consolidated framework best-practices file; include security, caching, logging, API/MCP design as sections within it
   • Per testing stack (1 file): Generate testing-best-practices.md
   • Per build/DevOps (1 file): Generate build-and-devops.md if build tools, Docker, or CI/CD are in the stack
2. Cross-check with existing .claude/rules/ files — if a global rule already covers a topic, mark it as "skip (covered by global rule: <filename>)"
3. For each selected rule file, note:
   • File name and paths glob patterns
   • Primary technologies and versions it applies to
   • ADR reference(s) tracing back to the decision
   • Sections to include (consolidated from the catalog)

Phase 2 output: A rule generation plan table:

Present this plan to the user for confirmation. The user may:

• Remove rules they consider unnecessary
• Add custom rule categories
• Adjust scope, paths, or priority

Proceed only after user approval.

Phase 3: Rule Generation — Write Rule Files

Goal: Generate each approved rule file with concrete, actionable, version-specific content using the Claude Code .claude/rules/ format.

Method: Read references/rule-file-template.md for the standard rule file structure with YAML frontmatter.

Execution rules:

1. Generate rules one file at a time, presenting each to the user for review before proceeding to the next
2. For each rule file: a. Follow the template structure from references/rule-file-template.md b. Include YAML frontmatter with paths for path-scoped rules, or omit for always-loaded rules c. Include the ADR reference header linking the rule to the technology decision d. Write Mandatory Rules (M-NNN) — non-negotiable best practices for the specific technology and version e. Write Recommended Rules (R-NNN) — strong suggestions with documented rationale f. Include DO/DON'T code examples in the project's primary language for every mandatory rule g. Add a Checklist section for pre-commit verification
3. Write each approved rule file to the project's .claude/rules/ directory
4. Respect existing global rules:
   • Never overwrite files in ~/.claude/rules/ (user's global rules)
   • Project-level rules go to <project-root>/.claude/rules/
   • If a project-level rule overlaps with a global rule, add a reference: > Extends global rule: ~/.claude/rules/<filename>
5. Content constraints:
   • All code examples, log messages, and exception messages must use English (per project global rule)
   • No hardcoded magic values — use named constants with environment variable support (per project global rule)
   • Every rule must be concrete and actionable, not vague platitudes
   • Prefer quantifiable thresholds over subjective guidance

Interaction model:

• Present ONE rule file at a time
• Allow the user to approve, modify, or reject each rule file
• If rejected, revise based on feedback and re-present

Phase 3 output: Complete set of rule files written to .claude/rules/.

Phase 4: Integration & Summary — Ensure Consistency

Goal: Verify all generated rules are consistent with each other and with existing global rules, then present a final summary.

Execution rules:

1. Cross-check all generated rule files for contradictions (e.g., one rule mandates a pattern another forbids)
2. Verify all ADR references are valid
3. Verify all paths patterns are correct and non-overlapping where it matters
4. Check that existing global rules (from ~/.claude/rules/ and project CLAUDE.md) are not contradicted by new rules
5. If conflicts are found, present them to the user for resolution

Phase 4 output: A final summary report:

1. Rules generated — count and file paths with their paths scoping
2. Rules skipped — count and reasons (covered by global rules)
3. Technologies covered — list of all technologies with corresponding rule files
4. ADR coverage — verify every ADR has at least one corresponding rule file
5. Global rule compatibility — confirm no conflicts with existing global rules
6. Recommended next steps — suggest running project-architecture-init if not yet done

Key Principles

• Consolidated files — merge related concerns into one file per domain (4–5 files total, not 15+)
• Paths-scoped — every rule file uses YAML frontmatter paths unless truly cross-cutting; this prevents all rules from loading into context simultaneously
• Code quality focus — prioritize coding standards, error handling, and best practices over operational/infra rules
• One rule file at a time — never present all rules simultaneously; allow user review per file
• Version-specific — rules must reference the exact technology version from the tech stack, not generic advice
• ADR-traceable — every rule file must link back to the ADR that confirmed the technology
• No duplication — check existing global rules before generating; reference rather than repeat
• Concrete over vague — "method body must not exceed 30 lines" beats "keep methods short"
• DO/DON'T examples — mandatory rules require both correct and incorrect code examples
• English code artifacts — all code, logs, and exceptions in generated rules use English
• Incremental validation — present each phase output to the user before proceeding

Resources

references/

• rules-catalog.md — Consolidated rule category catalog organized by technology domain, with the selection algorithm for determining which rules to generate and paths patterns for each category
• rule-file-template.md — Standard template structure for generated rule files using Claude Code YAML frontmatter format, including paths glob pattern reference and content guidelines