Equation 16 · The Economics, Energy, and Physical Limits of Tool Protocols and the Model Context Protocol
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The assumption doing the work in that formula — every schema injected in full, on every turn, uncompressed — is exactly the assumption Gorilla and ToolLLM abandoned once their tool catalogues grew past a few dozen entries, replacing blanket injection with retrieval that surfaces a handful of relevant tool descriptions per request instead of the whole catalogue [ 5 , 6 ] . That substitution changes from “every tool’s cost, always” to “a few tools’ cost, most of the time,” which is the only lever in the equation that scales sublinearly as the number of available tools grows. It is also, notably, a departure from what MCP’s own discovery model assumes by default:…
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The assumption doing the work in that formula — every schema injected in full, on every turn, uncompressed — is exactly the assumption Gorilla and ToolLLM abandoned once their tool catalogues grew past a few dozen entries, replacing blanket injection with retrieval that surfaces a handful of relevant tool descriptions per request instead of the whole catalogue [ 5 , 6 ] . That substitution changes from “every tool’s cost, always” to “a few tools’ cost, most of the time,” which is the only lever in the equation that scales sublinearly as the number of available tools grows. It is also, notably, a departure from what MCP’s own discovery model assumes by default: tools/list is designed to hand back the full capability set a server offers, and nothing in the base protocol specifies how a host should decide to show only part of that set to the model [ 1 ] .
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