How much does context cost an AI coding agent? grep vs graph vs LSP, measured across 936 runs

In my last post I described graphlens — what it does, how it works — and along the way I casually claimed that an agent "burns tokens grepping around a repo." I gave exactly zero numbers to back that up.

This post fixes that. Here are the measurements, the data, and a reproducible harness. Spoiler: the conclusion is not the one I expected going in, and that's the interesting part.

TL;DR

I took one agent (Claude Code), changed exactly one thing — which MCP server feeds it code context — and ran it over 26 tasks on apache/superset. Four "arms": filesystem (grep + read), graphlens (structural graph), serena (LSP), and codegraph. Three models (haiku / sonnet / opus), three seeds — 936 runs.

The headline: the answer flips depending on the kind of task.