Prompt Writing Skill

Overview

Core Principle: Context completeness over brevity. Agents cannot infer what you don't provide.

Target Users:

Claude Code delegating to subagents via Task tool
UI agents that need to generate prompts
Engineers writing system prompts or agent instructions

The CLEAR Framework

Use this mnemonic for every prompt you write:

| Letter | Component | Purpose | Key Question | |--------|-----------|---------|--------------| | C | Context | Background information | What does the agent need to know? | | L | Limitations | Constraints, prohibitions | What should NOT be done? | | E | Expectations | Output format, success criteria | What exactly should be returned? | | A | Actions | Step-by-step instructions | What steps to follow? | | R | Resources | Files, tools, references | What materials are available? |

C - Context

Complete background: project state, environment, history. Include file paths, versions, prior decisions.

L - Limitations

Explicit boundaries: DO NOT modify X, use only Y, forbidden patterns, compliance requirements.

E - Expectations

Exact output format: markdown structure, JSON schema, where to save, success criteria checklist.

A - Actions

Numbered steps, validation checkpoints, decision points, error handling guidance.

R - Resources

Required reading (file paths), available tools, reference implementations, examples.

Full guide with examples: reference/prompt-anatomy.md

Context Patterns

Critical Insight

Subagents have NO conversation history. Each invocation is completely fresh. They cannot infer context.

Three Strategies

| Strategy | When to Use | How | |----------|-------------|-----| | File-Based | Multi-step workflows | Save to file, pass path to next agent | | Embedded | Small contexts | Include all info directly in prompt | | Layered | Large contexts | Summary + references for deep-dive |

State Transfer Pattern

Agent 1 → Save results to `.claude/state/results/agent-{timestamp}.md`
Agent 2 → Read from that file path

Full patterns: reference/context-patterns.md

Output Format Quick Reference

| Pattern | Use Case | Key Feature | |---------|----------|-------------| | Structured Markdown | Comprehensive results | Tables, sections, test output | | Binary Verdict | Review/validation | PASS/FAIL first, then details | | Checklist | Multi-requirement | Progress tracking with status | | Condensed | Subagent responses | Max 3 findings, no verbose output |

Delivery Patterns

State directory: .claude/state/results/[agent]-[timestamp].md
Project output: output/[task-id]/[artifact].md
Inline: Return directly (use for summaries only)

Full templates: reference/output-specifications.md

Quality Checklist

Before sending any prompt, verify:

Context (C)

[ ] All background information included?
[ ] File paths explicit and complete?
[ ] No assumptions about prior knowledge?

Limitations (L)

[ ] Constraints clearly stated?
[ ] Prohibited actions explicit?
[ ] Scope boundaries defined?

Expectations (E)

[ ] Output format specified exactly?
[ ] Success criteria measurable?
[ ] Delivery location defined?

Actions (A)

[ ] Steps numbered and sequential?
[ ] Validation checkpoints included?
[ ] Error handling guidance provided?

Resources (R)

[ ] Required files listed with paths?
[ ] Available tools mentioned?
[ ] Examples provided where helpful?

Subagent-Specific

[ ] No implicit context assumptions?
[ ] State transfer mechanism defined?
[ ] Output format prevents overload?

Anti-Patterns Quick Reference

| Anti-Pattern | Problem | Solution | |--------------|---------|----------| | Context Amnesia | Assumes agent remembers | Embed all context explicitly | | Vague Expectations | "Give me a good result" | Specify exact format | | Implicit Constraints | "Follow best practices" | List specific requirements | | Unbounded Scope | "Improve the code" | Define precise boundaries | | Missing Resources | "Check the docs" | Provide file paths | | Output Overload | No format limits | Request condensed response |

Full examples with solutions: reference/anti-patterns.md

Templates

Ready-to-use templates for common scenarios:

| Template | Purpose | |----------|---------| | templates/subagent-delegation.md | Task tool delegation | | templates/code-task.md | Implementation tasks | | templates/research-task.md | Research/exploration | | templates/review-task.md | Code review/validation |

Quick Start

Choose template from templates/ matching your task type
Fill CLEAR sections systematically
Run checklist to verify completeness
Execute the prompt
Iterate if results don't match expectations

Remember: More context is almost always better. When in doubt, include it.

Troubleshooting

| Problem | Likely Cause | Solution | |---------|--------------|----------| | Irrelevant results | Insufficient context | Add explicit file references, examples | | Wrong format | Vague specification | Provide template with placeholders | | Unwanted changes | Missing constraints | Add explicit DO NOT statements | | Incomplete task | Unclear success criteria | Add specific acceptance criteria | | Agent asks questions | Ambiguous requirements | Make all decisions upfront |

Reference Documentation

reference/prompt-anatomy.md - Full CLEAR examples by language
reference/context-patterns.md - State transfer strategies
reference/output-specifications.md - Output format templates
reference/anti-patterns.md - Common mistakes and fixes