Agentic Retrieval in Azure AI Search

Agentic retrieval is currently in public preview. Features and capabilities may change.

Agentic retrieval is a multi-query pipeline designed for complex questions posed by users or agents in chat and copilot applications. It’s optimized for Retrieval Augmented Generation (RAG) patterns and agent-to-agent workflows.

What is Agentic Retrieval?

Agentic retrieval transforms how AI agents interact with your data by:

Query decomposition: Using an LLM to break down complex queries into focused subqueries
Parallel execution: Running multiple subqueries simultaneously for better coverage
Semantic reranking: Promoting the most relevant matches from each subquery
Unified response: Combining results into a modular, comprehensive answer

Key Capabilities

LLM Query Planning

Automatically breaks complex questions into targeted subqueries using chat history and context

Parallel Retrieval

Executes multiple searches simultaneously across indexed and remote knowledge sources

Semantic Reranking

Applies machine learning to surface the most relevant results for each subquery

Agent-Optimized Response

Returns structured output designed for agent consumption with grounding data and references

How It Works

Retrieval Process

Workflow Initiation

Application calls a knowledge base with a query and conversation history

Query Planning

Knowledge base sends query and history to an LLM, which analyzes context and breaks down the question into focused subqueries

Query Execution

Knowledge base sends subqueries to knowledge sources. All execute simultaneously using keyword, vector, or hybrid search

Semantic Reranking

Each subquery’s results undergo semantic reranking to identify the most relevant matches

Result Synthesis

System combines all results into a three-part response: merged content, source references, and execution details

Why Use Agentic Retrieval?

Complex Query Handling

Traditional search struggles with queries like:

“Find me a hotel near the beach, with airport transportation, and that’s within walking distance of vegetarian restaurants”

Agentic retrieval decomposes this into:

Hotels near beaches
Hotels with airport shuttle service
Hotels near vegetarian dining options

Query Expansion

Benefits:

Corrects spelling mistakes automatically
Adds synonyms and paraphrasing
Includes chat history context
Handles compound questions

Multi-Source Retrieval

Query across different knowledge sources simultaneously:

Indexed search indexes
Remote SharePoint sites
Public web data (Bing)
Microsoft OneLake
Azure Blob Storage

Architecture Components

Knowledge Base

Orchestrates the entire retrieval pipeline:

{
  "name": "my-knowledge-base",
  "description": "Customer support knowledge base",
  "knowledgeSources": [
    {"name": "product-docs"},
    {"name": "support-articles"},
    {"name": "sharepoint-kb"}
  ],
  "llmConnection": {
    "resourceId": "/subscriptions/.../openai",
    "deploymentName": "gpt-4o"
  },
  "semanticConfiguration": "my-semantic-config"
}

Knowledge Sources

Represent searchable content:

Indexed sources: Search indexes on Azure AI Search
Remote sources: Live data from SharePoint, Bing, or web APIs

{
  "name": "product-docs",
  "type": "searchIndex",
  "indexName": "products-index",
  "description": "Product documentation and specifications"
}

Required Components

Component	Service	Purpose
LLM	Azure OpenAI	Query planning and context analysis
Knowledge Base	Azure AI Search	Orchestration and parameter management
Knowledge Source	Azure AI Search	Wrapper for search indexes or remote data
Search Index	Azure AI Search	Stores searchable text and vectors
Semantic Ranker	Azure AI Search	L2 reranking for relevance

Response Structure

Agentic retrieval returns a three-part response:

1. Merged Content

Grounding data for LLM answer generation:

{
  "content": "Based on the search results...\n\nProduct A features...\n\nProduct B offers...",
  "references": [
    {
      "id": "ref1",
      "title": "Product A Documentation",
      "url": "https://..."
    }
  ]
}

2. Source References

Original documents for citation:

{
  "references": [
    {
      "referenceId": "ref1",
      "documentId": "doc123",
      "title": "Product A Documentation",
      "snippet": "Product A is designed for...",
      "score": 0.89,
      "source": "product-docs"
    }
  ]
}

3. Activity Log

Execution details for debugging:

{
  "activityLog": {
    "queryPlan": {
      "originalQuery": "best product for small business",
      "subqueries": [
        "products suitable for small business",
        "affordable business solutions",
        "SMB recommended products"
      ]
    },
    "execution": [
      {
        "subquery": "products suitable for small business",
        "source": "product-docs",
        "resultsCount": 15,
        "executionTimeMs": 45
      }
    ]
  }
}

Retrieval Reasoning Effort

Control LLM usage with reasoning effort levels:

Minimal
Low
Medium

Minimal Effort

No LLM query planning
Direct keyword and vector search
All knowledge sources queried
Fastest execution
Lowest cost

Use when:

Query is already well-formed
Speed is critical
Cost optimization is important

Example: Complex Query Decomposition

User Query

"I need a hotel in San Diego for next weekend that allows dogs and has a pool. 
My previous stay at the Marina Inn was too noisy."

Query Plan

The LLM generates subqueries:

Subquery 1: “pet-friendly hotels San Diego”
- Targets: Hotels allowing dogs
- Filter: PetsAllowed eq true
Subquery 2: “hotels with swimming pool San Diego”
- Targets: Pool amenities
- Filter: PoolAvailable eq true
Subquery 3: “quiet hotels San Diego NOT Marina Inn”
- Targets: Peaceful locations
- Excludes: Previous stay
- Context: User preference for quiet

Execution

Multi-Source Example

Knowledge Base Configuration

{
  "name": "enterprise-kb",
  "knowledgeSources": [
    {
      "name": "internal-docs",
      "type": "searchIndex",
      "alwaysQuery": false
    },
    {
      "name": "sharepoint-policies",
      "type": "remoteSharePoint",
      "alwaysQuery": true
    },
    {
      "name": "web-resources",
      "type": "web",
      "alwaysQuery": false
    }
  ],
  "retrievalReasoningEffort": "low"
}

Query Execution

User Query: “What is our vacation policy and industry best practices?” Routing Logic:

sharepoint-policies (always queried): Company policies
internal-docs (conditionally): HR documentation
web-resources (conditionally): Industry standards

Integration with Foundry Agent Service

Connect agentic retrieval to Microsoft Foundry agents:

Create Knowledge Base

Define knowledge base with indexed sources and vector fields

Connect to Foundry

Link knowledge base to Foundry Agent Service using connection string

Agent Configuration

Configure agent to use knowledge base for grounding

Query Execution

Agent automatically uses knowledge base for information retrieval

Performance Considerations

Latency Factors

Agentic retrieval adds latency due to:

LLM query planning (1-3 seconds)
Parallel subquery execution
Semantic reranking

Optimization Strategies

Use Faster Models

gpt-4o-mini for query planning
Reduces planning latency by 50-70%
Sufficient for most query decomposition tasks

Minimize LLM Processing

Set retrievalReasoningEffort to minimal when possible
Exclude LLM processing for simple queries
Use direct search for known patterns

Optimize Knowledge Sources

Consolidate indexes to reduce fan-out
Use alwaysQuery: false for optional sources
Provide clear descriptions for source selection

Summarize Message Threads

Limit chat history to recent messages
Summarize long conversations before processing
Reduces input token count

Cost Estimation

Billing Components

Azure OpenAI (query planning):
- Input tokens: Chat history + query
- Output tokens: Subqueries generated
- Model-specific pricing (e.g., gpt-4o, gpt-4o-mini)
Azure AI Search (agentic retrieval):
- Token-based: 1 million tokens per unit
- Free tier: 50 million tokens/month
- Pay-as-you-go after free quota

Example Cost Calculation

Scenario: 2,000 agentic retrievals per month Assumptions:

3 subqueries per retrieval
50 chunks reranked per subquery
500 tokens per chunk
2,000 input tokens (chat history)
350 output tokens (query plan)

Azure AI Search:

Total queries: 2,000 × 3 = 6,000
Total chunks: 6,000 × 50 = 300,000
Total tokens: 300,000 × 500 = 150 million
Cost: ~$3.30 USD

Azure OpenAI (gpt-4o-mini):

Input: 2,000 × 2,000 = 4M tokens × $0.15/1M =$ 0.60
Output: 2,000 × 350 = 700K tokens × $0.60/1M =$ 0.42
Cost: ~$1.02 USD

Total: ~$4.32 USD for 2,000 retrievals

Availability and Pricing

Agentic retrieval is available in selected regions during preview.

Supported Regions

Check region support documentation for current availability.

Pricing Plans

Plan	Description	Monthly Quota
Free	Default on all tiers	50M tokens
Standard	Pay-as-you-go after free quota	Unlimited

You are not notified when transitioning from free to paid quota. Monitor usage through Azure portal metrics.

When to Use Agentic Retrieval

Agentic retrieval is ideal for:

Complex Questions

Multi-part questions requiring decomposition and parallel search

Agent Workflows

Agent-to-agent communication needing structured responses

RAG Applications

Chat applications requiring high-quality grounding data

Multi-Source Scenarios

Querying across indexed and remote data sources

Next Steps

Create Knowledge Base

Set up your first knowledge base

Knowledge Sources

Learn about different knowledge source types

Create Index

Build an index for agentic retrieval

Query API

Explore the retrieval API reference

Getting Started

Core Concepts

Agentic Retrieval

Indexing

Queries

​Agentic Retrieval in Azure AI Search

​What is Agentic Retrieval?

​Key Capabilities

LLM Query Planning

Parallel Retrieval

Semantic Reranking

Agent-Optimized Response

​How It Works

​Retrieval Process

​Why Use Agentic Retrieval?

​Complex Query Handling

​Query Expansion

​Multi-Source Retrieval

​Architecture Components

​Knowledge Base

​Knowledge Sources

​Required Components

​Response Structure

​1. Merged Content

​2. Source References

​3. Activity Log

​Retrieval Reasoning Effort

​Example: Complex Query Decomposition

​User Query

​Query Plan

​Execution

​Multi-Source Example

​Knowledge Base Configuration

​Query Execution

​Integration with Foundry Agent Service

​Performance Considerations

​Latency Factors

​Optimization Strategies

​Cost Estimation

​Billing Components

​Example Cost Calculation

​Availability and Pricing

​Supported Regions

​Pricing Plans

​When to Use Agentic Retrieval

Complex Questions

Agent Workflows

RAG Applications

Multi-Source Scenarios

​Next Steps

Create Knowledge Base

Knowledge Sources

Create Index

Query API

Agentic Retrieval in Azure AI Search

What is Agentic Retrieval?

Key Capabilities

How It Works

Retrieval Process

Why Use Agentic Retrieval?

Complex Query Handling

Query Expansion

Multi-Source Retrieval

Architecture Components

Knowledge Base

Knowledge Sources

Required Components

Response Structure

1. Merged Content

2. Source References

3. Activity Log

Retrieval Reasoning Effort

Example: Complex Query Decomposition

User Query

Query Plan

Execution

Multi-Source Example

Knowledge Base Configuration

Query Execution

Integration with Foundry Agent Service

Performance Considerations

Latency Factors

Optimization Strategies

Cost Estimation

Billing Components

Example Cost Calculation

Availability and Pricing

Supported Regions

Pricing Plans

When to Use Agentic Retrieval

Next Steps