Agentic AI Notebook
Phase 9

Haystack Agents

~2 min read

Concept & How It Works

  • Key points are in the visual diagram above.

Why Does It Exist?

Teams already running Haystack for RAG can add agentic behavior — tool use, routing, multi-hop retrieval — without migrating to a new framework.

Real-World Analogy

Haystack Agents turn a library search desk into a research librarian who not only finds books but also calls external databases and synthesizes answers.
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Visual Workflows

What is Haystack Agents?

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Example

Scenario

Enterprise search agent: user query → agent decides between Confluence retriever, Jira tool, or Slack search → synthesizes unified answer.

Solution

In Agent Framework Landscape, apply Haystack Agents to this scenario: Enterprise search agent: user query → agent decides between Confluence retriever, Jira tool, or Slack search → synthesizes unified answer. Identify the inputs, run the technique, validate the output, and note one thing you would monitor in production.

Practice Task

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 Haystack Agents (e.g. model, temperature, top_k, or tool name), observe the difference in output, and write 2–3 sentences explaining what changed.

Code Walkthrough

Highlighted lines show where Haystack Agents happens in the code.

Haystack Agents
1from haystack.components.agents import Agent  # import dependencies2from haystack.tools import Tool  # import dependencies3
4search_tool = Tool(name="search_docs", description="Search internal wiki",5    function=wiki_search, parameters={"query": {"type": "string"}})6agent = Agent(chat_generator=generator, tools=[search_tool])7result = agent.run(messages=[{"role": "user", "content": "PTO policy 2026"}])

Commands to Remember

Commands to Remember

  • pip install llama-index # LlamaIndex workflows
  • pip install semantic-kernel # Microsoft Semantic Kernel
  • pip install smolagents # Hugging Face agents

Common Mistakes

  • Treating Haystack Agents as a black box without evaluation
  • Ignoring cost and latency in production
  • Skipping error handling for haystack agents

Cheat Sheet

Quick recap — the most important points from this module.

Cheat Sheet

quick ref
  • Haystack Agents
  • Pipeline
  • Toolset
  • ChatGenerator