Chapter 4: What Works (And What Doesn’t)
Based on real testing with complex projects, here are the patterns that succeed and fail.
✓ Highly Effective Uses (~90% reliability)
1. Core Identity Facts
| Chars | Example |
|---|---|
| 22 | “User name: Francesco” |
| 31 | “Company: 5Levels Intelligence” |
| 45 | “Location: Milan, Italy (CET timezone UTC+1)” |
2. Technical Architecture Facts
| Chars | Example |
|---|---|
| 57 | “Architecture: Two-layer client-heavy processing model” |
| 48 | “Backend stores only results, not raw data” |
| 35 | “Database: PostgreSQL 15, not MongoDB” |
3. Critical Constraints
| Chars | Example |
|---|---|
| 52 | “Must comply with LinkedIn Terms of Service (ToS)” |
| 64 | “Budget: €500K max (€300K development + €200K first-year ops)” |
| 41 | “Launch deadline: December 15, 2025 hard” |
4. Preferences & Technology Choices
| Chars | Example |
|---|---|
| 36 | “Prefers TypeScript over JavaScript” |
| 42 | “Hosting: Hetzner bare metal, not AWS” |
| 47 | “Query builder: Knex.js, never TypeORM” |
5. Project-Specific Terminology
| Chars | Example |
|---|---|
| 147 | “Stitching engine = cross-referencing data sources. NOT web scraping. NOT API calls. NOT automation.” |
| 86 | “Temporal Intelligence: Module detecting birthdays, job changes, work anniversaries” |
Moderately Effective Uses (~60-70% reliability)
1. Documentation Pointers
"Mobile strategy docs in 'Mobile and tablet extension strategy' chat from Nov 2"
Note: Less reliable than pure facts; use as supplement, not primary information
2. Workflow Preferences
"Prefers incremental development with frequent commits"
Note: Works sometimes, but Claude may still suggest big-bang approaches
3. Anti-Patterns
"NEVER suggest TypeORM. Always use Knex.js"
Note: Helps, but doesn’t prevent TypeORM mentions entirely
✗ Ineffective Uses (~30% reliability)
1. Behavioral Instructions
"Always check project documentation before answering"
Why: Claude has this in system prompt already; redundant
2. Complex Reasoning Patterns
"When discussing architecture, prioritize philosophy over implementation"
Why: Too abstract; Claude can’t reliably apply this
3. Conditional Logic
"If query is about mobile, search for mobile strategy chat first"
Why: Memory edits don’t support conditional logic
The Complete Reliability Matrix
| Use Case | Reliability | Recommendation |
|---|---|---|
| Names, dates, locations | ~95% | ✓ Always use |
| Tech stack choices | ~90% | ✓ Always use |
| Architecture facts | ~90% | ✓ Always use |
| Constraints (budget, deadline) | ~85% | ✓ Always use |
| Terminology definitions | ~85% | ✓ Always use |
| Anti-patterns with “NEVER” | ~70% | ⚠️ Use with backup |
| Documentation pointers | ~60% | ⚠️ Extract facts instead |
| Workflow preferences | ~50% | ⚠️ Low priority |
| Behavioral instructions | ~30% | ✗ Use Project Instructions |
| Conditional logic | ~10% | ✗ Don’t use |
Memory Edits vs. Project Instructions
Critical Understanding: Memory edits work together with Project Instructions — they’re not alternatives.
Project Instructions: The Essential Framework
Project Instructions define:
- HOW Claude should work (process, methodology, workflow)
- What role Claude plays (specialized professional, domain expert)
- Response structure and format requirements
- Writing style rules and preferences
- Decision-making frameworks to follow
Memory Edits: The Amplifier
Memory edits don’t replace Project Instructions — they AMPLIFY them.
While Project Instructions define the working framework, memory edits ensure Claude never loses sight of critical facts — even with 48 documentation files and complex conversations.
The Complete System
PROJECT INSTRUCTIONS (Essential Framework)
"HOW to work, what process to follow"
Role, methodology, structure, style
+
MEMORY EDITS (Critical Facts Focus)
"THESE specific facts, always visible"
Names, constraints, key architectural facts
+
DOCUMENTATION (Comprehensive Detail)
"All the detailed information"
Implementation guides, API docs, specs
+
ACTIVE STEERING (Real-time Guidance)
"Today's specific corrections"
In-conversation clarifications
Together: Claude works like an expert professional on your team.