MCP vs CLI vs API: How Tool Design Drives Your AI Token Bill
sanjaykalra · x · 2026-08-23
This article examines how the design of the tool layer in agentic AI systems acts as a major, hidden cost driver, specifically comparing MCP servers, CLI tools, and direct APIs.
- Hidden Context Tax: Every time an agent reasons, the schemas of all available tools are loaded into context. A single well-documented tool can cost 200–1,400 tokens.
- MCP Overhead: MCP requires loading structured JSON schemas for exposed tools. Popular servers with extensive tool lists can significantly inflate context costs on every turn or session start.
- Token Economics: The choice between communication protocols is not just an engineering preference but a token-economics decision that compounds across multi-turn workflows.
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