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Hi, I'm Steve Jamison, AI Research and Engineering Leader at Jellyfish.

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I'm here to show you why tokens are the cheap part.

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The research that I'll present is drawn from the Jellyfish platform,

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the industry's largest set of engineering workflow data joined to AI telemetry data.

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It's no secret that AI costs are climbing.

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They're up 60x from this time last year.

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The use cases are wide and varied.

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The models and harnesses are getting much better.

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The implications are exciting.

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But discussions around budget and spend are not as much fun.

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These conversations involve your peers and senior leadership and the board.

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not always the easiest audiences, especially when you don't have the right data.

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And it's real money these days. Output is up too. Merged PRs per engineer are up 43% over the same

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one-year horizon. This is phenomenal. We've not seen productivity inputs like this,

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especially on this timescale. There's plenty of research and anecdotal data to know

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that AI and agentic coding are driving these throughput gains.

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Heck, even our charts show the correlation.

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Notice where the inflection points are.

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AI spend increased in early 2026

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when throughput gains start a steady increase of their own.

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There's a tension with these two numbers, though.

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How do you reconcile them?

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Spend is up 60x.

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Throughput is also up 43%.

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Is that good? Bad?

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43% is a big number.

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But so is 60x. How do you know if you're spending enough? Is there more productivity gain locked behind a checkbook? Should we increase spend 50% 2x more? Or how do you know if you spent too much?

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I'm sure many of you have felt the tension here.

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The CFO or board are asking for the receipts of the spend.

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Can you show them?

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Will merged PRs are up 43% satisfy them?

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Also, what happens if you cap use and spend?

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Are you stopping from setting tokens on fire?

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Or are you stumping further efficiency gains?

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You can ask peers at other companies what they're paying.

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For many, it's still a moving target, though.

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But how do you equate that to your org?

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Surely, just comparing their bill to yours isn't adequate.

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We've heard the reports of companies spending $100K, $500K, even millions on AI,

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setting, then resetting their AI budgets as reality sets in.

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Ultimately, these two numbers can't tell the story.

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And even together, they missed the biggest line on the cost side.

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These two numbers leave out the biggest cost of all, developer salary.

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AI is making developers more productive on a scale we haven't seen before.

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It isn't just another tool, it's intelligence.

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This intelligence dramatically changes how much each dev can produce.

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That's why we need to think about its cost differently.

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Not often the side is overhead, but it's part of what it takes to produce each PR.

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We're going to call this intelligence costs of a PR.

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What you pay your engineers plus what you pay for AI, put them together in one cost bucket.

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AI is about 2.5% of the cost to produce another unit of merged code.

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Salary is the other 97.5%.

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This is in line with other reported figures, and this data is from August 2026.

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Here, tokens are the cheap part. But that's current relative costs, not dollars. Let's

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look at what happened to the cost of merged PR over the last year.

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The dollar cost of a merged PR fell 26% over the last year.

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Not PRs created, but PRs merged.

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Review time has factored in, and some level of quality gates has been cleared.

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That decline in cost per merged PR includes a 60x increase in AI costs over the same time frame.

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The change is nearly universal, too.

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83% of the companies we studied showed a drop in cost per PR.

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What does this tell us?

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The additional throughput gains are spreading salary thinner across PRs,

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and this is happening faster than the AI costs are increasing.

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What's the range in token spend?

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We ranked companies by token usage, then grouped them into quintiles or fifths.

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The range here is quite large. The lightest group, about 0.3% of the cost of a PR is AI. This represents about 60 million tokens per dev per month.

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The top 20% of AI spend per dev, we're going to call the heaviest spend group.

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There, 8.5% of the PR cost is AI.

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This represents about 2.5 billion tokens per dev per month,

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about two orders of magnitude more than the lightest group.

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We'll use these groups on the next slides to see how token spend influences other metrics.

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First, PR throughput measured as merged PRs per dev, split by the same AI spend quintiles on the previous slide.

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The bottom four-fifths of spenders sell PR throughput gains of around 40%, give or take.

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But the heavy spend group

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improved more at a 67% increase.

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More AI spend led to more throughput gains.

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let's look at the cost per PR.

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Positive results are seen again across the board.

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Cost per PR is dropping for all AI usage groups.

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However, again, the heaviest fifth, so the companies that spent the most, improved the most.

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They saw a cost per PR decrease of 32% over the last year.

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The other four groups saw about a 25% decrease in cost per PR.

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Investing and spending more on AI fueled more of an improvement in cost per PR.

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compared to peers who leaned in less.

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So we saw that the same as we saw in the population average,

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cost per PR changes are driven largely by PR throughput, not by AI spend.

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The heavy spenders experience PR throughput gains of 67%

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compared to about 40-ish percent for their peers.

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Spreading the same salary across more PRs in the month

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has more of an effect than the rising AI costs,

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because tokens are the cheap part.

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This is not to say that orgs should light tokens on fire

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and spend with a banding.

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Here, we're looking at tokens used on the horizontal axis

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and cost per PR on the vertical axis.

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There's a steep drop at the beginning

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where relative small AI spend results in large gains initially.

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As token usage increases, the cost per PR improvement decreases.

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This is diminishing returns.

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I want to stress, though, diminishing returns is not the same as no returns.

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We're seeing that the top 10% are spending 8x the tokens compared to the median

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and achieving a 25% lower cost per PR.

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There will be a time when tokens aren't the cheap part, but by and large, for most companies out in the wild, we're not close to that threshold.

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More tokens leads to more PRs, which leads to a lower cost of delivery.

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So far, we've talked about companies.

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Next, I'd like to take a tangent and talk about a study we did with developers.

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Here we looked at developer weeks with heavy token use compared to the same developer weeks with lower token use.

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Here we saw the same phenomenon just at the individual level.

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Compare each developer's heavy agent skill weeks with their own weeks without skills.

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They spend about twice as much on tokens, merge 27% more PRs, and reach PR costs about 18% less once salary and tokens are counted together.

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there are two fair curiosities i get when i talk about this work first does faster work

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result in worse work and second are the more prs

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the throughput gains that we're seeing are they being driven by smaller chunks of work

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First curiosity is cheaper, faster work, worse work.

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If AI makes PRs faster and cheaper, are we just shipping more mistakes?

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One proxy for this is reverts. Merge PRs that undo an earlier PR.

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The heaviest fifth started lowest before most of the token growth.

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And revert rates dropped slightly for every group.

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though these deltas are just slightly below the noise in the data.

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It's not evidence of improvement here.

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However, more importantly, we're not seeing any worrying signs of rampant or severe quality issues

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with higher token spends and faster PR throughput.

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it. The second curiosity, is throughput driven by smaller PRs? And this is demonstrably no,

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not smaller PRs. In fact, AI is driving an increase in lines of code generated per PR.

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This is no surprise to the devs in the room. Raise your hand if you've rolled your eyes at

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for both unnecessary inline AI comments,

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or a file full of mostly irrelevant tests.

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Gen AI likes to generate code.

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Also, the bar to create is low for devs,

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and there's a pool to do more per PR

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instead of spending up another ticket.

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It's just one, maybe two prompts,

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and I'll handle this edge case,

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or I can combine this and that element.

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Fewer PRs to wrangle.

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This doesn't mesh well with the PR review stress

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folks are feeling these days though.

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Also, AI is just becoming more capable,

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so we're getting more ambitious.

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It is beyond this talk to dig into what's actually driving

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those level of lines of code changes.

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However, the increase in PR throughput

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is not coming from smaller PRs.

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This is intuitive for most, but it's still good to verify.

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Back to the opening question.

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Is 60x more spend worth 43% more output?

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You can't tell in isolation.

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You should track both.

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They are important numbers, but they're supporting metrics.

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AI spend per PR is the intelligence that you're buying as a resource to help make your devs go faster.

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PRs per engineer is what you're getting with that spend.

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However, looking at those hides the trade-off.

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But put salary into the equation and take the ratio of cost to throughput.

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And there you get your answer.

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Cost per PR is down 26% over that same time period.

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It's clear AI is driving cost efficiencies despite the increasing bills.

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and the AI spend needed to get those efficiencies is small, relatively speaking.

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AI is still a sliver of what a PR costs, 2.5% on average,

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under 10% for the heavy spender group.

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Tokens are the cheap part.

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In the range that we see, more spend kept paying.

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heavier token users saw 67% PR throughput gain compared to 40% for their lower spend peers.

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This drove cost per PR down 32% compared to about 25% for the lower spend peers.

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Looking at the PR cost to token ratio curve,

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The top 10% of company months by token usage resulted in 8x the tokens, but 25% lower cost per PR compared to the median.

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AI is making developers more productive on a scale we haven't seen before.

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It isn't just another tool, it is intelligence, which changes how much each dev can produce.

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That's why we need to think about its costs differently.

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Not off to the side as overhead, but as part of what it takes to produce each PR.

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You need to add the AI spend and the human spend, the human salary spend, together to calculate your real costs per PR.

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This isn't to say spend frivolously.

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Sure, you should watch for runaway jobs.

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You should track your AI spend.

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I'm not saying don't look at how much AI spend is going in each PR.

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I'm saying don't let that be your driving metric.

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A new framing might steer how and when you think about other investments,

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like integrating model routers, post-training your own model,

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implementing token limits, et cetera.

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Will you get more efficiencies out of trying to control AI costs or by continuing to invest in things that increase throughput, like more AI enablement?

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Either way, track the total intelligence costs, human plus artificial, per PR every month next to that AI bill and next to the PR throughput.

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How are you trending? Is throughput continuing to improve?

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What about those cost efficiencies, the cost to deliver?

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Watch reverts and quality metrics beside all of this as a counterweight.

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We don't

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AI slot mucking up the gears.

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So heading into budget season, bring cost per PR to the table. Not just your token bill, not just the throughput bump.

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The bill tells you what you spent. Cost per PR tells you whether it worked.

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And right now, for most companies, it says keep investing.

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Tokens are the cheap part to get efficiency gains.

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Well done. You made it to the end.

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Here's how you can stay up to date with our latest research, which again draws from the largest engineering workflow and AI telemetry data set in the industry.

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You can follow me on LinkedIn, my colleagues, or Jellyfish.

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subscribe to our sub stack,

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or you can check out our Jellyfish blog on the website.

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If you want help tracking your org's engineering workflow

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and AI effectiveness, including cost per merged PR,

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go to our website and book a demo or reach out to me

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and I'll get you connected to the right folks.

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Again, I'm Steve Jamison,

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AI research and engineering leader at Jellyfish.

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Thanks for watching.

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Cheers.
