fusengine/agent-design

Agent Design

Skill for designing high-performance AI agents following 2025 patterns.

References

• patterns.md - Load when: choosing an agent architecture (Single Agent, Agent+Tools, Orchestrator, Pipeline, Network, Supervisor, Hierarchical, Meta-Prompting) or comparing their trade-offs
• workflows.md - Load when: implementing APEX, TDD, Explore-Plan-Code, Code Review, or Debugging workflows for an agent
• templates.md - Load when: writing a full agent definition (production frontmatter + sections) or a Claude Code agent template
• anti-patterns.md - Load when: reviewing an agent design for common mistakes (omniscient agent, implicit instructions, missing error handling)

Fundamental Distinction

Workflows vs Agents

| Type | Control | When to use | |------|---------|-------------| | Workflow | Code orchestrates LLM | Predictable tasks, need for control | | Agent | LLM directs its actions | Flexibility, adaptive decisions |

Golden rule: Start simple, add complexity if necessary.

Minimal Agent Structure

Agent:
  identity: Who am I?
  capabilities: What can I do?
  tools: What tools do I have?
  constraints: What are my limits?
  workflow: How should I proceed?

For the complete production structure and the Claude Code agent template, see templates.md.

Fresh Eyes Principle

Key 2025 concept: Each sub-agent must have a "fresh" context.

❌ Bad: Pass entire history to each sub-agent
✅ Good: Give only necessary information

Orchestrator:
  - Keeps complete history
  - Extracts relevant context for each sub-agent
  - Synthesizes results

Design Checklist

Before creating an agent

• [ ] Is the objective clear?
• [ ] Would a simple workflow suffice?
• [ ] What tools are needed?
• [ ] What guardrails are required?

During design

• [ ] Is identity well defined?
• [ ] Is workflow explicit?
• [ ] Are error cases handled?
• [ ] Are examples relevant?

After creation

• [ ] Standard case tests?
• [ ] Edge case tests?
• [ ] Security tests (jailbreak)?
• [ ] Acceptable performance?

For anti-patterns to avoid during design, see anti-patterns.md.

Forbidden

• Never create an agent without explicit workflow
• Never give access to all tools without necessity
• Never ignore the principle of least privilege
• Never forget security guardrails