Seven months, $28,335, across five agent harnesses. For a lot of people running agents right now that's a heavy week.

I publish that number on /trends and it updates itself, so I've had a while to look at it. What I expected to find was a story about cost. What's actually in the data is a story about scheduling, and the number that tells it is this one: 0.7% of my agent's tool calls happened between midnight and six in the morning.

Claude Code and Codex arrive at 0.7% independently. Different vendors, different session formats, 1,432 sessions between them, and I only noticed the match because I ran the same script twice and thought I'd double-counted.

The shape of the bill

Agent tool calls by hour of day

00:00–06:00awake

View as table

Hour	Tool calls	Human turns
00:00	1,221	44
01:00	0	0
02:00	101	4
03:00	21	0
04:00	6	0
05:00	69	2
06:00	388	34
07:00	2,382	187
08:00	11,783	803
09:00	12,482	795
10:00	17,250	1,130
11:00	15,958	1,070
12:00	12,145	867
13:00	14,312	1,034
14:00	18,266	1,342
15:00	15,536	1,167
16:00	20,507	1,341
17:00	19,476	1,329
18:00	11,964	629
19:00	7,244	352
20:00	6,255	389
21:00	6,391	360
22:00	4,857	296
23:00	2,859	179

That's 201,473 tool calls bucketed by the hour I was awake for them. It looks like a workday because it is one. The peak is 16:00. The trough is 03:00, and the trough is empty.

An agent that runs unattended doesn't produce this shape. If you leave loops running, your histogram flattens — the overnight band fills in, because that's the entire point of leaving them running. Mine has a hole in it, and the hole is where I was asleep.

The weekly view says the same thing. Weekdays average $176 a day; weekends average $67. The spend tracks my calendar, not a scheduler's.

What the spend actually bought

Agent spend by month, all harnesses

View as table

Month	Spend	Active days	Per day
Jan	$21	9	$2
Feb	$240	21	$11
Mar	$533	26	$21
Apr	$3,930	30	$131
May	$6,556	29	$226
Jun	$5,268	27	$195
Jul	$6,289	30	$210
Aug (partial)	$5,498	14	$393

The curve is boring until April, where it goes up 7.4× in one month and then stays there. That's not a pricing change and it isn't a new model. April is when I stopped running one conversation at a time and started running agents in parallel git worktrees, which is the single largest change in how much I spend and the single largest change in how much lands.

Underneath it: 9,350 commits across 145 repositories since January, concentrated in sdk-generator, cloud and appwrite.

I want to be careful with that number, because it's the one most likely to be wrong in my favour. sdk-generator emits bulk generated output, so its 1,933 commits are not 1,933 units of thought. And only 205 commits carry a Co-authored-by trailer for an agent, which is not a measure of anything except how inconsistently I remember to keep the trailer. Take 9,350 as a statement of scale and nothing finer.

The leash is fifteen actions long

The interesting ratio isn't dollars per commit. It's how much rope the agent gets before I say something.

	Claude Code	Codex	Combined
Sessions	200	1,232	1,432
Human turns	3,016	10,336	13,352
Tool calls	29,438	171,040	200,478
Tool calls per human turn	9.8	16.5	15.0
Interrupts	218	1,829	2,047
Median human turns per session	7	4	—
Median session length	34 min	16 min	—

Fifteen actions, then I say something. That is the whole working relationship in one number, and it has stayed roughly constant while the spend went up 300×. What April changed was how many leashes I hold at once, not how long any one of them is.

The interrupt count is the part I didn't expect. 2,047 times I stopped a run in progress — a little over ten times per active day. I'd have guessed a tenth of that. Interrupting is so cheap that it stopped registering as an event, which is a strange thing to learn about your own habits from a log file.

296 of 1,432 sessions were single-turn: ask, receive, done. That's 21%. The other 79% are conversations. The median session is four to seven human turns over sixteen to thirty-four minutes, which is not automation. It's pairing, with a partner who types faster than me and needs checking.

The part that argues against me

I have around 130 skills installed. Across all my Claude Code transcripts, they've been invoked 52 times.

Twenty-six of those are one skill, release-sdk, which is a genuine repetitive chore. After that: artifact-design six times, dataviz four, sentry-cli three, and then a tail of skills fired exactly once.

The infrastructure behind those 130 is not casual. There's a harness-neutral root at ~/.agents/skills with a lock file that pins each skill to a GitHub commit, symlinked outward into Claude Code, Codex and Pi, with a config listing fifteen harnesses it knows how to install into. ~/.codex/AGENTS.md, ~/.gemini/GEMINI.md and ~/.config/opencode/AGENTS.md are byte-identical, all three md5 295f62fc. I built a distribution system for my own instructions.

And then I mostly don't invoke the things it distributes. I type instead.

There are two readings. The generous one is that skills are a library, and a library you consult four times a year is still worth having. The honest one is that I enjoy building the workshop more than I use the tools in it, and that 130-installed-52-fired is a tooling habit rather than a workflow.

Both are probably true. What neither reading supports is the idea that any of this productivity came from automation running without me.

The choice, and what it costs

Here's the objection I can't fully answer: is 0.7% restraint, or just circumstance?

Right now the marginal cost of running agents overnight is about as low as it will ever be. Everything is subsidised. I have the budget, five harnesses configured, worktree isolation already working, and a skills system that can install into fifteen agent runtimes. Every ingredient for a 24/7 loop is sitting on this machine, and the histogram still has a hole in it.

So it's a choice, and it's worth being clear about what I'm buying with it. Fifteen tool calls is roughly how much work I can hold in my head and still meaningfully review. Past that I'm not reviewing, I'm accepting. The 2,047 interrupts are the mechanism: they only happen because I'm watching, and I'm only watching because the run is short enough to watch.

The cost is real. There's work I could have shipped overnight and didn't. The trade is that I can still explain every one of those 9,350 commits, which matters more to me in a codebase I'll be on call for.

$28,335 over seven months is a modest bill by current standards. I don't think that's because I was careful with money. I think it's because a leash fifteen actions long is inherently cheap, and the thing it's actually buying is that I never stopped being the one holding it.