LlamaIndex Workflows

• Key points are in the visual diagram above.

RAG agents need retrieval, reranking, synthesis, and validation as distinct steps. Workflows make each step testable and replace implicit chain logic with explicit event handlers.

LlamaIndex Workflows are a factory assembly line with sensors: each station emits a signal (event) when done, triggering the next machine.

Scenario

Query workflow: `QueryEvent` → retrieve chunks → `RetrieveEvent` → rerank → `SynthesizeEvent` → answer with citations.

Solution

In Agent Framework Landscape, apply LlamaIndex Workflows to this scenario: Query workflow: `QueryEvent` → retrieve chunks → `RetrieveEvent` → rerank → `SynthesizeEvent` → answer with citations. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.

Do this before moving to the next module — reading alone is not enough.

Open the Code Walkthrough below and run it locally. Change one parameter related to LlamaIndex Workflows (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.

Highlighted lines show where LlamaIndex Workflows happens in the code.

1from llama_index.core.workflow import Workflow, step, StartEvent, StopEvent, Event  # import dependencies2
3class QueryEvent(Event):  # define a data structure or component4    query: str5
6class AnswerEvent(Event):  # define a data structure or component7    answer: str8
9class RAGWorkflow(Workflow):  # define a data structure or component10    @step11    async def retrieve(self, ev: StartEvent) -> QueryEvent:12        return QueryEvent(query=ev.query)  # return the result13
14    @step15    async def synthesize(self, ev: QueryEvent) -> StopEvent:16        return StopEvent(result=AnswerEvent(answer="..."))  # return the result

• Treating LlamaIndex Workflows as a black box without evaluation
• Ignoring cost and latency in production
• Skipping error handling for llamaindex workflows

Quick recap — the most important points from this module.