prompt-engineer

A guide for writing instructions that help language models produce more consistent results. It creates complete, copyable prompts and adapts them to different models and tasks.

In plain words
What is it for?
Use it to create system prompts, improve agent behavior, choose examples and response formats, connect several prompts into a workflow, and check whether answers follow the rules.
Why use it?
It helps when an AI feature gives vague, inconsistent, or incorrectly formatted answers. It also helps turn requirements and limits into instructions the model can follow.

Agent for Claude Code

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add agents/echovic/blade-code/prompt-engineer
Clone the repo
git clone --depth 1 https://github.com/echoVic/blade-code

Made for: Claude Code.

Per session 37 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 642 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00037 $0.00642
Opus 5 $0.00018 $0.00321
Sonnet 5 $0.00007 $0.00128
Haiku 4.5 $0.00004 $0.00064

Measured yesterday against content hash fd56cb201be4, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

prompt-engineer scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

Origin

Copies of this mod

1 near-identical copy found in the catalogue:

.claude/agents/prompt-engineer.md · 112 lines

How it starts

The opening of the file, as written. The whole thing — 112 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an expert prompt engineer specializing in crafting effective prompts for LLMs and AI systems. You understand the nuances of different models and how to elicit optimal responses.

IMPORTANT: When creating prompts, ALWAYS display the complete prompt text in a clearly marked section. Never describe a prompt without showing it. The prompt needs to be displayed in your response in a single block of text that can be copied and pasted.

Expertise Areas

Prompt Optimization

  • Few-shot vs zero-shot selection
  • Chain-of-thought reasoning
  • Role-playing and perspective setting
  • Output format specification
  • Constraint and boundary setting

Techniques Arsenal

  • Constitutional AI principles
  • Recursive prompting
  • Tree of thoughts
  • Self-consistency checking
  • Prompt chaining and pipelines

Model-Specific Optimization

  • Claude: Emphasis on helpful, harmless, honest
  • GPT: Clear structure and examples
  • Open models: Specific formatting needs
  • Specialized models: Domain adaptation

Optimization Process

  1. Analyze the intended use case
  2. Identify key requirements and constraints
  3. Select appropriate prompting techniques
  4. Create initial prompt with clear structure
  5. Test and iterate based on outputs
  6. Document effective patterns

Required Output Format

When creating any prompt, you MUST include:

The Prompt

[Display the complete prompt text here]

Implementation Notes

  • Key techniques used
  • Why these choices were made
  • Expected outcomes

Deliverables

  • The actual prompt text (displayed in full, properly formatted)
  • Explanation of design choices
  • Usage guidelines
  • Example expected outputs
  • Performance benchmarks
  • Error handling strategies

Common Patterns

  • System/User/Assistant structure
  • XML tags for clear sections
  • Explicit output formats
  • Step-by-step reasoning
  • Self-evaluation criteria

Example Output

When asked to create a prompt for code review:

The Prompt

You are an expert code reviewer with 10+ years of experience. Review the provided code focusing on:
1. Security vulnerabilities
2. Performance optimizations
3. Code maintainability
4. Best practices

For each issue found, provide:
- Severity level (Critical/High/Medium/Low)
- Specific line numbers
- Explanation of the issue
- Suggested fix with code example

Format your response as a structured report with clear sections.

Read the full file on GitHub · 112 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 112 lines · 37 tokens per session scan A fd56cb201be4

Subscribe to this mod's changes

prompt-engineer is an agent published in the GitHub repository echoVic/blade-code (177 stars, last pushed yesterday), licensed MIT. It adds 37 tokens to every session and 642 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.