Prompt Craft - Claude 4 Best Practices
Craft effective prompts for Claude workers using proven patterns.
Core Principles
1. Be Explicit
Claude 4.x follows instructions precisely. Use action verbs.
| Less Effective | More Effective |
|---|---|
| "Can you suggest improvements?" | "Update the function to improve performance." |
| "Look at this code" | "Find and fix the null check bug" |
| "Help with testing" | "Write unit tests for the auth module" |
2. Add Context/Motivation
Explain WHY, not just WHAT. Claude generalizes from explanations.
| Less Effective | More Effective |
|---|---|
| "NEVER use ellipses" | "Never use ellipses since the TTS engine won't pronounce them correctly." |
| "Always add error handling" | "Add error handling so users see helpful messages instead of stack traces." |
3. Natural Skill Triggers
Use natural language, avoid aggressive markers.
| Avoid | Use |
|---|---|
| "CRITICAL: You MUST use this tool when..." | "Use the X skill for Y." |
| "ALWAYS: This is REQUIRED" | "Use this approach when..." |
| "IMPORTANT!!!: Never forget to..." | "Remember to..." |
4. Positive Framing
Tell Claude what TO do, not just what to avoid.
| Less Effective | More Effective |
|---|---|
| "Don't write long functions" | "Keep functions under 20 lines" |
| "Avoid complex logic" | "Use simple, readable patterns" |
Prompt Structure
markdown
## Context [1-2 sentences: Why this work matters, what problem it solves] ## Task [Clear, explicit action instruction using action verbs] ## Approach [Optional: Skill hints, patterns to follow, key considerations] Use the [skill] skill for [specific purpose]. ## Key Files [3-5 most relevant files to start with] - path/to/main/file.ts - path/to/related/file.ts ## When Done [How to complete: close issue, what to include in summary] Close issue: bd close ISSUE-ID --reason "summary"
Skill Matching
Match skills based on content:
| Content Signal | Suggested Skill |
|---|---|
.tsx, .jsx, React | frontend-development |
| terminal, xterm, resize | xterm-js |
| auth, login, session | better-auth |
| database, SQL, query | databases |
| API, REST, endpoint | backend-development |
| CSS, styling, theme | ui-styling |
| docs, markdown | docs-seeker |
Subagent Hints
Claude 4.5 naturally delegates. Add hints when beneficial:
markdown
Use subagents in parallel to scaffold Dashboard, Settings, and Profile pages.
markdown
Use an Explore agent to find the relevant authentication files first.
Parallelization Hints
For tasks with independent subtasks:
markdown
These components can be developed in parallel: - HeaderComponent - FooterComponent - SidebarComponent
Complexity Guidelines
| Prompt Length | When to Use |
|---|---|
| Short (3-5 lines) | Simple bug fixes, single-file changes |
| Medium (10-15 lines) | Feature work, multi-file changes |
| Long (20+ lines) | Complex features, architectural changes |
Rule: If you need more than 20 lines, the issue might need breaking down.
Anti-Patterns
Avoid these common mistakes:
- •Overloading: Too many skills, too many files, too much context
- •Vague tasks: "Make it better" without specific criteria
- •All caps: CRITICAL, IMPORTANT, MUST - creates anxiety, not clarity
- •Negative framing: Lists of don'ts without corresponding dos
- •No completion criteria: Worker doesn't know when they're done