# Agent-Side Search Patterns

## Purpose

Documents recommended patterns for agent-side query expansion and reranking, which are caller responsibilities rather than engine features. These patterns are communicated via MCP tool descriptions.

## Requirements

### Requirement: Query expansion guidance in tool description

The `kb_search` MCP tool description SHALL include guidance on query expansion as a recommended pattern for complex queries.

#### Scenario: Tool description includes expansion pattern
- **WHEN** an agent reads the `kb_search` tool description
- **THEN** the description SHALL include guidance such as: "For complex queries, consider expanding into 2-3 variant phrasings and calling this tool multiple times, then deduplicating results by chunk_id"

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### Requirement: Reranking guidance in tool description

The `kb_search` MCP tool description SHALL include guidance on agent-side reranking as a recommended pattern for improving precision.

#### Scenario: Tool description includes reranking pattern
- **WHEN** an agent reads the `kb_search` tool description
- **THEN** the description SHALL include guidance such as: "For precision, rerank the returned results using your own judgement based on relevance to the original question"

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### Requirement: No engine-side LLM dependency

The engine SHALL NOT require or use any external LLM API for search operations. Query expansion and reranking SHALL remain entirely agent-side concerns.

#### Scenario: Engine has no LLM dependency
- **WHEN** the engine is deployed without any `ANTHROPIC_API_KEY` or similar LLM API configuration
- **THEN** all search operations SHALL function fully, with no degraded results or missing features