---
title: "Parallelism Isn't Free: The Real Cost of Fanning Out Agents"
canonical: https://dxdev.com/blog/2026-05-28_quota-arithmetic-of-parallelism/
datePublished: 2026-05-28
---
The work log for that morning says I ran a fleet of about 30 concurrent runs "after the author noted main-context iteration wasn't burning quota fast enough."

## Thirty runs at once

The previous night's session took the blog queue from 2,635 down to 38 and produced 106 AI-drafted posts, 16 newsletters and 19 social posts. They went through multiple codex review rounds and a framework audit, and the first 8 went live. The log says main-context iteration wasn't burning quota fast enough.

So I fanned out to about 30 concurrent runs. By the end of that session the live set had gone from 8 to 63 posts, and every new one had twitter and linkedin variants. The session ran 7h 26m.

That was the stretch where I lost track of what I was spending.

## The accounting

The weekly retro puts it in one sentence: parallel Opus sessions burned quota faster than I tracked during the blog push.

My work log does record tokens and wall time for single calls, like `codex exec (medium, 95614t, 364.6s)`. A serial loop gives you a gauge you can read between iterations. A fleet removes the gaps between iterations, so the spend shows up after the fact.

The log also records research on a workstation purchase because the 11-year-old laptop was choking at 10-15 agents. The fleet was about 30. That note puts the limit at 10-15 agents.

## Volume against a number I could count

The same morning's log shows four codex framework findings closed: a `.png.png` OG image regression, an unmounted `CodeCopyButton`, hardcoded `SystemPage` colors, and broken tag URL encoding.

The week came to 1,260 commits across 23 repos, 174 sessions, and 533 commits on Wednesday alone. A big number and a controlled number are different things. The commit count is exact. The retro says the quota burned faster than it was tracked.

The workstation is researched and priced but not bought, so the laptop is still the ceiling.

A fleet sets your rate of spend. Mine was about 30 concurrent runs, and the quota burned faster than it was tracked.