How does prompt routing or prompt rewriting happen inside the server?

How does prompt routing or prompt rewriting happen inside the server?

Prompt routing is how MCP Servers decide which model, tool, or API should handle each step of the task. Example workflow:

1. Agent says: “Scan ports and generate a report”
2. MCP Server:
   • Parses “scan ports” → selects Nmap
   • Parses “generate report” → selects Claude or GPT
   • Rewrites these as sub-prompts internally

This internal routing is based on:

• Task keywords
• Available tools
• Cost/performance preferences
• Agent history or prior outcomes

Some advanced servers support prompt rewriting, where the task is restructured or expanded before execution, e.g., turning “scan this domain” into “run Nmap + perform WHOIS + check against blacklist.”