curiositech/ai-engineer

AI Engineer

Expert in building production-ready LLM applications, from simple chatbots to complex multi-agent systems. Specializes in RAG architectures, vector databases, prompt management, and enterprise AI deployments.

Decision Points

RAG Component Selection

Query Type Assessment:
├── Simple FAQ/Knowledge Lookup
│   ├── Document Count < 1000 → Chroma + text-embedding-3-small
│   └── Document Count > 1000 → Pinecone + text-embedding-3-large
├── Technical/Code Documentation  
│   ├── Budget Constrained → bge-large + pgvector
│   └── Performance Critical → voyage-2 + Weaviate
└── Conversational/Multi-turn
    ├── Memory Required → Agent pattern + context management
    └── Stateless → Standard RAG pipeline

Reranking Decision:
├── Precision Critical (legal, medical) → Always use Cohere Rerank
├── Latency < 200ms → Skip reranking, tune retrieval
├── Budget Constrained → Cross-encoder (bge-reranker-large)
└── Default → Cohere Rerank with top-10 → top-3

Database Selection:
├── Existing Postgres → pgvector extension
├── Need Hybrid Search → Weaviate or Qdrant
├── Managed Service → Pinecone
└── Self-hosted/Local → Chroma or Qdrant

Model Routing Strategy

Complexity Assessment:
├── Keywords Only (FAQ) → Claude Haiku
├── Single Document Reference → Claude Sonnet  
├── Multi-document Synthesis → Claude Opus
└── Code Generation → Claude Sonnet with tools

Token Budget Check:
├── < 1K tokens → Any model
├── 1K-4K tokens → Sonnet/GPT-4
├── 4K-32K tokens → Claude Opus
└── > 32K tokens → Chunk and summarize first

Agent vs RAG Decision

Task Classification:
├── Static Knowledge Query → Pure RAG
├── Need External APIs → Agent with tools
├── Multi-step Reasoning → Agent with planning
├── Real-time Data Required → Agent with live tools
└── Simple Q&A → RAG with fallback to agent

Failure Modes

Semantic Mismatch Cascade

Symptoms: Good retrieval precision but poor answer relevance, users say "close but not quite right" Detection Rule: If semantic similarity > 0.8 but user satisfaction < 60% Root Cause: Query and document embeddings optimized for different semantic spaces Fix: Switch to domain-specific embedding model or implement query expansion with synonyms

Context Window Overflow

Symptoms: Responses become generic, model ignores specific retrieved context, inconsistent answers Detection Rule: If context utilization ratio < 30% and response generality score > 0.7 Root Cause: Too many irrelevant chunks diluting relevant information Fix: Implement stricter relevance threshold (>0.8) and dynamic context selection

Tool Hallucination Loop

Symptoms: Agent makes up API calls, references non-existent functions, infinite retry cycles Detection Rule: If tool call success rate < 50% or iteration count > max_iterations * 0.8 Root Cause: Model trained on different tool schemas than implementation Fix: Add tool validation layer and explicit error handling in agent system prompt

Embedding Drift Degradation

Symptoms: Gradual decline in retrieval quality over time, seasonal performance drops Detection Rule: If monthly average retrieval@5 drops > 10% from baseline Root Cause: Domain language evolves but embedding model remains static Fix: Implement embedding model retraining pipeline or switch to adaptive embeddings

Response Latency Creep

Symptoms: P95 latency increases gradually, user complaints about slow responses Detection Rule: If P95 response time > 2x baseline for 7 consecutive days Root Cause: Vector index degradation, context size inflation, or model endpoint saturation Fix: Implement index optimization schedule, context pruning, and multi-model load balancing

Worked Examples

Example: Customer Support Chatbot Implementation

Initial Requirements: "Build a chatbot that can answer questions about our 500-page product documentation"

Step 1: Architecture Decision

• Document count: 500 pages → Use Pinecone for scalability
• Query type: Mixed FAQ + troubleshooting → Hybrid search needed
• Latency requirement: < 3 seconds → Include reranking but optimize

Step 2: Implementation Walkthrough

// Novice approach - would use basic similarity search
const chunks = await vectorDb.query(queryEmbedding, { topK: 5 });

// Expert approach - considers relevance thresholds
const rawChunks = await vectorDb.query(queryEmbedding, { 
  topK: 20, 
  threshold: 0.7  // Ensure minimum relevance
});

// Expert adds reranking step novice would skip
const reranked = await reranker.rank(query, rawChunks);
const finalChunks = reranked.slice(0, 3);

// Expert includes fallback handling
if (finalChunks.length === 0) {
  return await fallbackToGeneralSupport(query);
}

Step 3: Performance Optimization Discovery

• Initial P95 latency: 4.2 seconds (above requirement)
• Analysis: 60% of time spent in reranking
• Trade-off Decision: Switch from Cohere Rerank to local cross-encoder
• Result: P95 latency → 2.1 seconds, slight quality drop (92% → 89% satisfaction)
• Expert Insight: For support use case, speed > perfect accuracy

Step 4: Failure Scenario Handling

• Discovered 15% of queries were about features not in documentation
• Novice: Would return "I don't know"
• Expert: Added escalation detection and handoff to human agent

Final Architecture: Pinecone + local reranker + agent escalation = 89% automation rate at 2.1s P95

Quality Gates

• [ ] Retrieval@5 accuracy > 85% on evaluation dataset
• [ ] Average response latency < 3 seconds for P95
• [ ] Context utilization ratio > 60% (model uses retrieved information)
• [ ] Hallucination rate < 5% (responses not supported by retrieved context)
• [ ] User satisfaction score > 80% over 30-day rolling window
• [ ] Token cost per query < predefined budget threshold
• [ ] System uptime > 99.9% excluding planned maintenance
• [ ] PII detection rate > 95% (no personal info in responses)
• [ ] Embedding model performance stable (no >10% monthly degradation)
• [ ] Error handling covers all failure modes with graceful degradation

Not-For Boundaries

Do NOT use this skill for:

Prompt Engineering Tasks → Use prompt-engineer instead

• Optimizing prompt templates and instructions
• A/B testing prompt variations
• Chain-of-thought prompt design

ML Model Training/Fine-tuning → Use ml-engineer instead

• Training custom embedding models
• Fine-tuning LLMs on domain data
• Model architecture research

Data Pipeline Engineering → Use data-pipeline-engineer instead

• ETL processes for training data
• Data validation and cleaning workflows
• Batch processing systems

Infrastructure/DevOps → Use backend-architect instead

• Kubernetes deployment strategies
• Database optimization and sharding
• Load balancer configuration

Analytics and Monitoring Setup → Use chatbot-analytics instead

• Conversation flow analysis
• User behavior tracking
• Performance dashboard creation

Delegate When:

• Task requires deep ML expertise → ml-engineer
• Focus is on conversation design → prompt-engineer
• Need infrastructure scaling → backend-architect
• Want usage analytics → chatbot-analytics
• Building non-AI features → Relevant specialist skill