Reference · 14 parts · 63 sections
All necessary topicsof AI engineering, in three voices
A dense, citation-backed reference for the fundamentals every applied AI engineer needs — from tokens and tool use to retrieval, context, and agent loops. Each topic ships in three voices: the engineer's version (with code and diagrams), the layman's version (plain English with analogies), and বাংলা ব্যাখ্যা.
AI ENGINEERING · REFERENCE
AppliedAIEngineering
From tokens to agents · English + বাংলা
INSIDE
14 parts · 63 sections
Structure
The 14 parts
Read in order, or jump to the part you need. Each part stands on its own.
LLM Fundamentals
from an engineer's lens
Tokens, tokenization & context cost · Model families & trade-offs · Closed vs open-weight models · Sampling parameters · Streaming vs non-streaming · Structured outputs & JSON mode · Function calling & tool use · Multimodal inputs (vision, audio, PDFs) · Embedding models & reranker models · Reasoning models & extended thinking
10 sections
0/10Prompt Engineering
System vs User vs Assistant message design · Few-shot, role prompting & personas · Chain-of-thought, ReAct & reflection patterns · XML / Markdown structuring for reliable parsing · Prompt templating & variable injection · Prompt versioning — prompts as code · Output parsers & graceful failure handling · Prompt injection defense at the prompt layer
8 sections
0/8Context Engineering
the new "prompt engineering"
Context window budgeting · Conversation summarization & rolling memory · Prompt caching strategies · Hierarchical memory · Context compression & pruning · Tool result truncation strategies · Lost in the Middle & mitigation
7 sections
0/7RAG and Knowledge Systems
Chunking strategies: fixed, semantic, structural, late chunking · Vector databases: Qdrant, Pinecone, Weaviate, pgvector, Chroma, Milvus · Hybrid search (BM25 + vector) & reciprocal rank fusion · Query rewriting, expansion & HyDE · Multi-hop retrieval & agentic retrieval · Reranking: Cohere, BGE, Voyage · Metadata filtering & structured retrieval · GraphRAG & knowledge-graph augmentation · Document parsing pipelines: Unstructured, LlamaParse, Docling · Multimodal RAG: images, tables, charts
10 sections
0/10Agents and Agentic Systems
What an agent actually is · The four canonical agent loops · Single-agent vs multi-agent orchestration · State machines and workflow graphs · Agent memory: scratchpad, semantic, procedural · Human-in-the-loop checkpoints · Subagents and delegation patterns · Error recovery, retries, and self-correction · Long-running agents and durable execution · Browser and computer-use agents
10 sections
0/10Tool Use and Integrations
Tool/function schema design · Parallel tool calling · Model Context Protocol (MCP) · Sandboxed code execution · API wrappers as tools · Tool result formatting for LLM consumption
1 section
0/1Inference
API-based vs self-hosted inference · Inference servers · Quantization: GGUF, AWQ, GPTQ, INT4/INT8 · KV cache, prefix caching, speculative decoding · Continuous batching and throughput tuning · Latency vs throughput (TTFT, TPS) · GPU economics, edge inference, on-device models · Inference providers
1 section
0/1LLMOps and Observability
Tracing · Token, cost, and latency tracking · Prompt and agent versioning · A/B testing prompts and models in production · Replay and debugging · Drift detection (silent behaviour changes) · Feedback loops
1 section
0/1Evaluation Engineering
Offline evals: golden datasets, regression tests · LLM-as-judge · RAG metrics: faithfulness, answer relevance, context precision/recall · Agent evals: task success, trajectory, tool-call accuracy · Synthetic data generation for evals · Frameworks · Online evals on production traffic · Red teaming and adversarial testing
1 section
0/1Cost and Performance Optimization
Model cascading (cheap → expensive routing) · Caching: semantic, output, prompt · Batch APIs for non-real-time workloads · Distillation (small model from big) · Prompt compression (LLMLingua-style) · Token budgeting per feature · Model gateways: LiteLLM, Portkey, OpenRouter
1 section
0/1Safety, Security, and Guardrails
Prompt injection (direct and indirect) · Jailbreak resistance · Data exfiltration via tool calls and rendered links · Content moderation · Guardrail frameworks: NeMo Guardrails, Guardrails AI · PII redaction in inputs and outputs · Rate limiting and abuse prevention · Output validation against schemas · Audit logging for compliance
1 section
0/1Multimodal Engineering
Vision: image understanding, OCR-via-LLM, document AI · Voice agents: STT, TTS, realtime APIs · Image generation · Video generation · ComfyUI, Replicate, Fal for media pipelines
1 section
0/1AI Application Architecture
Streaming over SSE / WebSockets / HTTP chunked · Background jobs and queues for long agent runs · Idempotency and resumability · Multi-tenant prompt and key management · Fallback chains across providers · Feature flags for prompts and models · API design patterns for AI features
1 section
0/1Visual Learning Resources
ten interactive guides that show how AI works
Transformer Explainer: watch a model predict the next token · LLM Visualization: a 3D tour inside a GPT · 3Blue1Brown: neural networks and transformers, animated · The Illustrated Transformer: Q, K and V, explained with pictures · TensorFlow Playground: train a tiny network and break it · A Visual Guide to Attention Variants: MHA, GQA, MLA, sliding window and more · A Visual Guide to Mixture of Experts: routers, experts and load balancing · LLM Inference Handbook: from prompt to first token and beyond · Neuronpedia: look at what features inside a model mean · Embedding Atlas by Apple: a visual map of your embeddings
10 sections
0/10