Tool Selection

Overview

tool_selection is a decision plugin that controls how tools are chosen for a matched route.
It supports two modes:

• add: retrieve tools from a tools database
• filter: filter tools that are already present in the incoming request

It aligns to fragments under config/plugin/tool-selection/.

Key Advantages

• Separates route decision logic from tool retrieval/filter behavior.
• Supports both database-driven tool addition and request-tool semantic filtering.
• Keeps compatibility with route-local tool policies while making selection behavior explicit.

What Problem Does It Solve?

Different routes need different tool-selection behavior. Some routes should add tools from a curated database, while others should keep only the most relevant tools from the caller-provided set. tool_selection provides one plugin contract for both cases, with per-route controls such as threshold, top_k, and preserve behavior.

When to Use

• when a decision should add the most relevant tools from tools_db
• when a decision should semantically filter caller-provided tools
• when per-route tool selection mode must be explicit and configurable

Configuration

Use this fragment under routing.decisions[].plugins:

plugin:
  type: tool_selection
  configuration:
    enabled: true
    mode: filter
    relevance_threshold: 0.55
    preserve_count: 2

For add mode:

plugin:
  type: tool_selection
  configuration:
    enabled: true
    mode: add
    top_k: 5