Week 09 — LangGraph orchestrator¶

At a glance

Phase 3: Agents + Protocols · Starts: Mon 23 Nov 2026 · Planned: 16h 45m

Build: Capstone: LangGraph orchestrator (state, nodes, conditional edges, Postgres checkpointer)

By day¶

System Design · 45 min · Kafka internals: log, partitions, consumer groups, offsets, ordering guarantees → Message queues & streaming (Kafka) w09-sd-1
DSA · 25 min · Count Good Nodes in Binary Tree + Validate Binary Search Tree → Trees: DFS, BFS, BST · resource w09-dsa-1
Python · 20 min · Rep: async generators to stream LangGraph events through FastAPI → asyncio in depth: TaskGroups, cancellation, backpressure w09-py-1
Communication · 30 min · Grammar: Active vs passive voice, and when to use each → Week 09 drills · day 1 w09-comm-1

Agentic AI · 60 min · LangChain Academy 'Intro to LangGraph' modules 1-2: StateGraph, reducers, conditional edges, checkpointers → LangGraph: graphs, state, checkpoints · resource w09-ai-1
DSA · 30 min · Kth Smallest Element in a BST → Trees: DFS, BFS, BST · resource w09-dsa-2
Communication · 30 min · Vocabulary: Precision with numbers: roughly, approximately, marginally, materially → Week 09 drills · day 2 w09-comm-2

DSA · 25 min · Construct Binary Tree from Preorder and Inorder Traversal → Trees: DFS, BFS, BST · resource w09-dsa-3
Architecture · 45 min · Sagas (orchestration vs choreography) + transactional outbox — microservices.io patterns → Sagas, outbox & distributed transactions · resource w09-arch-1
Python · 20 min · Rep: Pydantic TypeAdapter + model_validate_json performance on large tool payloads → Pydantic v2 in depth w09-py-2
Communication · 30 min · Speaking drill: Question intonation and turn-taking → Week 09 drills · day 3 w09-comm-3

Agentic AI · 60 min · LangGraph 1.x deep dive: persistence, threads, time travel, streaming modes; rebuild the triage router as a graph → LangGraph: graphs, state, checkpoints · resource w09-ai-2
Java/Spring AI · 30 min · Spring AI tool calling: @Tool methods, ToolCallback, returnDirect — expose service-status as a tool → Tool calling & MCP servers in Spring AI · resource w09-java-1
Communication · 30 min · Idioms & phrasal verbs: Project phrasal verbs: roll out, scale up, sign off → Week 09 drills · day 4 w09-comm-4

System Design · 45 min · Delivery semantics: at-least-once + idempotent consumers, transactional/exactly-once in Kafka and its limits → Message queues & streaming (Kafka) w09-sd-2
DSA · 25 min · Binary Tree Maximum Path Sum → Trees: DFS, BFS, BST · resource w09-dsa-4
Python · 20 min · Rep: generator send()/close() and yield from — build a lazy trace reader → Iterators, generators & context managers w09-py-3
Communication · 30 min · Writing: Blameless postmortem prose → Week 09 drills · day 5 w09-comm-5

Agentic AI · 120 min · Capstone build: LangGraph orchestrator (classify → retrieve → act → draft) with PostgresSaver checkpointer and streaming to FastAPI SSE → LangGraph: graphs, state, checkpoints · resource w09-ai-3
DSA · 30 min · Serialize and Deserialize Binary Tree → Trees: DFS, BFS, BST · resource w09-dsa-5
Java/Spring AI · 30 min · Spring AI MCP client: connect a ChatClient to an existing MCP server (filesystem) over stdio → Tool calling & MCP servers in Spring AI w09-java-2
Communication · 30 min · Record & shadow: Question intonation and turn-taking → Week 09 drills · day 6 w09-comm-6

System Design · 45 min · Written design: notification system — channels, templating, preferences, rate limiting, retries, dedupe → Notification system w09-sd-3
Architecture · 30 min · Write ADR 009 for capstone: outbox for ticket-creation side effects triggered by the agent graph → Sagas, outbox & distributed transactions · resource w09-arch-2
Staff+ · 30 min · Read lethain on influence/alignment; list stakeholders for adopting the capstone at work and what each cares about → Influence without authority & alignment · resource w09-staff-1
Communication · 30 min · Soft skills + weekly review: De-escalating conflict → Week 09 drills · day 7 w09-comm-7
Review · 60 min · Explain-it-back: LangGraph state + reducers + checkpoints; flashcards on Kafka semantics and sagas → LangGraph: graphs, state, checkpoints w09-rev-1