mikeparcewski/agentic-patterns

Agentic Patterns

Reference guide for proven agentic architecture patterns and common anti-patterns to avoid.

Core Patterns

| Pattern | Use when | Example | Tradeoffs | |---------|----------|---------|-----------| | Sequential | Linear workflow, clear dependencies, predictable stages | Research → Analyze → Draft → Review | Simple coordination; bottlenecks if any agent is slow | | Hierarchical | Complex task decomposable into subtasks; central coordination | PM agent delegates to designer / dev / QA | Clear accountability, scales; single point of failure at parent | | Collaborative | Diverse perspectives matter; no clear lead | Multiple reviewers collaborating on code review | Rich outputs; needs conflict resolution + consensus | | Autonomous | Tasks are fully independent; parallel execution | Multiple monitoring agents checking different services | Max parallelism; no shared learning or coordination | | Human-in-the-Loop | High-stakes decisions, regulatory gates, human feedback | Agent drafts report; human approves before sending | Adds latency; ensures safety and quality | | ReAct | Dynamic environments; need adaptive behavior on feedback | Debug agent: try fix → observe tests → adapt | Flexible; high token/latency cost for reasoning | | Plan-Execute | Predictable environment; planning overhead justified | Multi-step pipeline with known transformations | Efficient; brittle if environment changes | | Reflection | Quality > speed; self-improvement valuable | Writer drafts → critiques → refines | Higher quality; more tokens and latency |

See refs/pattern-catalog.md for full descriptions and implementation notes per pattern.

Anti-Patterns Quick Reference

1. God Agent: Single agent doing everything. Split responsibilities.
2. Tight Coupling: Agents depend on internal implementation details. Use interfaces.
3. Missing Guardrails: No constraints on agent actions. Add validation and limits.
4. Deep Nesting: Agents calling agents calling agents. Flatten hierarchy.
5. No Observability: Can't see what agents are doing. Add logging and tracing.
6. Sequential Bottleneck: Everything waits for slowest agent. Add parallelism.
7. Context Bloat: Passing entire history to every agent. Compress and filter.
8. Redundant Agents: Multiple agents doing same thing. Consolidate.
9. Hardcoded Prompts: Prompts baked into code. Externalize and version.
10. Missing Timeouts: Agents can run forever. Add time and resource limits.

Pattern Selection Decision Tree

Is task decomposable into subtasks?
├─ YES: Is there a clear lead/coordinator role?
│   ├─ YES: Use Hierarchical
│   └─ NO: Use Collaborative
└─ NO: Does task require adaptation based on results?
    ├─ YES: Can you plan all steps upfront?
    │   ├─ YES: Use Plan-Execute
    │   └─ NO: Use ReAct
    └─ NO: Do you have multiple independent tasks?
        ├─ YES: Use Autonomous
        └─ NO: Use Sequential

Add Human-in-the-Loop gates for any high-stakes decisions. Add Reflection layer when quality is critical.

Combining Patterns

Patterns are composable:

• Hierarchical + ReAct: Parent plans, children adapt execution
• Sequential + Reflection: Each stage includes self-review
• Collaborative + Human-in-Loop: Peer review with human arbitration
• Autonomous + Hierarchical: Independent teams with team leads

Pattern Anti-Affinities

Avoid these combinations:

• Plan-Execute + ReAct: Contradictory - either plan upfront or adapt dynamically
• Autonomous + Tight Coordination: Defeats the purpose of autonomy
• Deep Hierarchies + Reflection: Exponential token cost

Quick Start

1. Identify if task is decomposable (subtasks?) or atomic
2. Identify if execution is predictable (plan?) or dynamic (adapt?)
3. Identify if agents should coordinate (hierarchy/collaboration) or work independently
4. Check anti-patterns list against current design
5. See refs/pattern-catalog.md for detailed examples

References

• refs/pattern-catalog.md - Detailed pattern descriptions with implementation examples
• refs/anti-patterns-design.md - Design anti-patterns (God Agent, Tight Coupling, Missing Guardrails, Deep Nesting, No Observability)
• refs/anti-patterns-operational.md - Operational anti-patterns (Sequential Bottleneck, Context Bloat, Redundant Agents, Hardcoded Prompts, Missing Timeouts)