Phase 3 Instructions

# Phase 3: Create Instructions — The Routing Layer

How do I write effective Project Instructions? This reference covers Phase 3: creating Instructions that act as a CONDUCTOR, routing to both operational and reference knowledge files through concrete query examples and edge case handling.

Key terms: Project Instructions, routing layer, conductor pattern, query routing, operational retrieval, reference retrieval, combined retrieval, query biasing

## Phase 3 Overview

Instructions are the routing layer of your knowledge system. They tell Claude WHAT knowledge exists and WHEN to retrieve it. Instructions do NOT contain the knowledge itself—that lives in operational and reference files.

**Deliverable:** INSTRUCTIONS.md ready to paste into Project Instructions field.

**Target size:** 4,000-8,000 characters. If longer, you're putting content in Instructions that should be in knowledge files.

**Template:** Use `templates/routing-instruction-template.md` for the full template.

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## The Conductor Pattern

**Instructions are a conductor, not a container.**

The conductor of an orchestra:
- Knows what music exists (content index)
- Knows when each section plays (query routing)
- Keeps the orchestra coordinated (edge case handling)
- Does NOT contain every note (that's in the knowledge files)

### What Instructions MUST Contain

| Component | Target Size | Purpose |
|-----------|-------------|---------|
| Core Purpose | 200-400 chars | Irreducible statement of what system does |
| System Architecture | 300-500 chars | Overview of what knowledge exists |
| Query Routing | 2,000-3,000 chars | Concrete retrieval mappings |
| Content Index | 1,500-2,500 chars | Domain details for precise routing |
| Edge Case Handling | 400-600 chars | Vague input, gaps, out-of-scope |

### What Instructions Should NOT Contain

- Detailed phase-by-phase workflows → put in operational files
- Complete decision frameworks → put in operational files
- Methodology explanations → put in reference files
- Examples and templates → put in reference files
- Extensive constraints lists → put in operational files

**Rule of thumb:** If it's more than a few sentences, it's a knowledge file, not an instruction.

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## Instruction Components

### Component 1: Core Purpose

The irreducible statement of what this system fundamentally DOES. This cannot be retrieved; it must be immediately present.