AI Engineer · Published 2026-10-13

Tokens Are the Cheap Part — Steve Jamison, Jellyfish

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Summary

Overview

  • Speaker: Steve Jamison
  • Channel: AI Engineer
  • Main topic: Engineering workflow analytics and AI cost vs. throughput dynamics
  • Purpose: To reframe how engineering leaders evaluate AI spend and productivity by analyzing the relationship between token consumption, developer throughput, and total delivery costs. Steve Jamison from Jellyfish presents empirical research drawn from the industry's largest set of engineering workflow and AI telemetry data (covering Sep 2025 to Aug 2026). He demonstrates that while AI spend has increased 60x and AI spend accounts for a tiny fraction of merged PR costs, the true cost driver is developer salary. Higher token consumption correlates with higher PR throughput and lower overall cost per merged PR, proving that tokens are the cheap part and intelligence costs of a PR are dominated by human salary.

Topic Map

AI Spend and Output Trends

  • Explanation: Examination of AI spend and output metrics over a one-year horizon from Jellyfish research.
  • Key claims:
    • AI spend per PR is up 60x over the past year.
    • Merged PRs per engineer are up 43% over the same period.
    • AI spend inflection points correlate with steady increases in throughput gains.
  • Examples:
    • 60x increase in AI spend per PR between September and August.
  • Terminology:
    • AI spend per PR
    • PRs per engineer
    • throughput gains
  • Why it matters: Highlights a tension between surging AI costs and productivity metrics that CFOs and leadership scrutinize.

Intelligence Cost of a PR

  • Explanation: Breaking down the cost buckets of a merged pull request between human salary and artificial intelligence.
  • Key claims:
    • AI represents about 2.5% of the cost to produce a unit of merged code.
    • Salary represents the other 97.5%.
    • Tokens are the cheap part of producing software.
  • Examples:
    • 97.5% human salary vs. 2.5% artificial intelligence cost breakdown in August 2026.
  • Terminology:
    • Intelligence cost of a PR
    • human spend
    • artificial spend
  • Why it matters: Demonstrates that focusing solely on AI token bills misses the largest cost component: developer salary.

Token Spend Quantiles and Impact on Throughput and Cost

  • Explanation: Analyzing companies and developers grouped by token usage quintiles to see the impact on PR throughput and cost per PR.
  • Key claims:
    • The heaviest fifth of token spenders saw a 67% increase in PR throughput.
    • Cost per PR fell for all groups, but the heaviest fifth saw a 32% decrease in cost per PR.
    • Spreading the same developer salary across more PRs has a larger effect than rising AI costs.
  • Examples:
    • Lightest token spenders use ~60M tokens/dev/month; heaviest spenders use ~2.5B tokens/dev/month (8x more tokens).
  • Terminology:
    • Token quintiles
    • PR throughput
    • heaviest fifth
    • diminishing returns
  • Why it matters: Proves that higher token consumption drives higher throughput, leading to lower delivery costs despite higher AI bills.

Key Points

Tokens are a tiny fraction of total delivery costs

  • Explanation: AI spend accounts for only about 2.5% of the cost to produce a merged PR, while developer salary accounts for 97.5%.
  • Evidence: Jellyfish research data from August 2026 showing 97.5% human salary vs 2.5% AI.
  • Practical implication: Engineering leaders should not throttle token usage out of fear of AI bills when salary is the dominant cost.

More token usage correlates with higher throughput and lower cost per PR

  • Explanation: Developers and companies using significantly more tokens achieve higher PR throughput per engineer, which spreads salary costs thinner across more output.
  • Evidence: Heaviest token fifth achieved 67% PR throughput gains and a 32% drop in cost per PR.
  • Practical implication: Investing more in AI enablement improves delivery efficiency and lowers total cost per PR.

Frameworks, Models & Processes

Intelligence Cost of a PR

  • How it works: Combines human salary spend and AI spend into a single cost bucket to evaluate the true unit cost of merged code.
  • Components:
    • Human salary spend (97.5%)
    • Artificial intelligence spend (2.5%)
  • When to use: When evaluating AI ROI and budgeting for engineering productivity tools.

Examples & Case Studies

Analyzed companies and developers grouped by token usage quintiles over a year.

  • Illustrates: The impact of token consumption on PR throughput and cost per PR.
  • Lesson: Heaviest token users achieved greater throughput gains and lower cost per PR despite spending 8x more on tokens.

Actionable Takeaways

  • Immediate:
    • Track total intelligence cost (human + artificial) per PR every month.
    • Do not let AI token spend be the primary driving metric for engineering efficiency.
  • Strategic:
    • Frame AI investments around cost of delivery rather than raw token bills.
    • Encourage heavy, effective AI usage to drive throughput and lower delivery costs.
  • Questions to investigate:
    • Are your developers leveraging AI to increase PR throughput?
    • How does your organization's token spend compare to industry medians and top performers?

Claims Worth Verifying

  • AI spend is up 60x over the past year. (empirical metric)
  • AI accounts for 2.5% of the cost of a merged PR while salary accounts for 97.5%. (empirical metric)
  • Heaviest token spenders achieved a 67% increase in PR throughput and 32% decrease in cost per PR. (empirical metric)

Notable Quotes

"Tokens are the cheap part." (at 0:08) "What you pay your engineers plus what you pay for AI, put them together in one cost bucket." (at 5:36) "Cost per PR changes are driven largely by PR throughput, not by AI spend." (at 11:56) "Tokens are the cheap part to get efficiency gains." (at 27:21)

Compressed Summary

  • AI spend is up 60x while merged PRs per engineer are up 43%.
  • AI accounts for only 2.5% of a merged PR cost while salary makes up 97.5%.
  • Heaviest token users achieved 67% throughput gains and 32% lower cost per PR.
  • Total intelligence cost per PR fell 26% over the year.
  • Keywords: tokens, productivity, engineering, throughput, costs
  • Core insight: Tokens are the cheap part of software delivery; intelligent AI usage increases developer throughput and ultimately lowers total cost per PR.

Core insights

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Mental Modelmedium noveltystrong evidence

The correct optimization target for AI-assisted engineering is a single unified cost bucket per unit of delivered output (human spend + AI spend per merged PR), not the token bill in isolation. AI is only ~2.5% of that bucket, so any optimization that attacks the token line is optimizing the wrong 97.5%.

Why it matters

Teams building agent harnesses, routers, and cost guardrails typically instrument and optimize inference spend because it is legible and attributable. If the dominant cost is the human in the loop, then token-efficiency work can be locally successful and globally negative-value, while work that raises output per unit of human attention is where the leverage is.

Generalization

For any AI-augmented workflow with a large fixed human cost per unit of output, model the objective as total blended cost per accepted artifact, and treat inference spend as a small variable term whose only value is in reducing the number of human cycles per artifact.

AI accounts for only about 2.5% of the cost to produce a merged PR, while developer salary accounts for 97.5%.
Open source video
What you pay your engineers plus what you pay for AI, put them together in one cost bucket.
Open source video
Empirical Resulthigh noveltystrong evidence

Unit cost is throughput-driven, not spend-driven: because salary is a quasi-fixed cost, spreading the same human spend across more merged PRs lowers cost per PR faster than rising AI spend raises it. A 60x increase in AI spend per PR coexisted with a 26% decline in total intelligence cost per PR.

Why it matters

This inverts the usual financial intuition that a 60x growth in a cost line is a budget emergency. It gives a concrete mechanism: the denominator (artifacts shipped per person) moved enough to swamp a 60x numerator increase. Engineers designing evaluation and routing policies should therefore measure artifacts-per-human-cycle rather than cost-per-call.

Generalization

In systems where a large fixed cost is amortized over throughput, optimizing the small marginal cost is dominated by any intervention that raises throughput, even at order-of-magnitude higher marginal spend.

AI spend per PR is up 60x over the past year.
Open source video
Total intelligence cost per PR fell 26% over the year.
Open source video
Cost per PR changes are driven largely by PR throughput, not by AI spend.
Open source video
Empirical Resulthigh noveltymoderate evidence

Cohorting populations by token-spend quintile yields a dose-response style signal: the heaviest fifth of token spenders realized 67% higher PR throughput and a 32% reduction in cost per PR, while cost per PR fell for every group. Heavy consumption is not (in this dataset) evidence of waste.

Why it matters

It supplies an empirical counter-argument to token-throttling as a default governance stance, and it suggests a reusable analytical pattern: bucket users or agents by resource consumption and measure outcome-per-cost per bucket rather than reporting a single aggregate spend number.

Generalization

Resource-consumption quintile analysis is a generalizable measurement harness for any agent platform: it converts a raw spend dashboard into a dose-response curve that exposes both returns and the point of saturation.

The heaviest fifth of token spenders saw a 67% increase in PR throughput.
Open source video
Cost per PR fell for all groups, but the heaviest fifth saw a 32% decrease in cost per PR.
Open source video
Tokens are the cheap part to get efficiency gains.
Open source video
Architecturemedium noveltymoderate evidence

Producing a unit economics metric of this kind requires joining three otherwise siloed telemetry planes: AI usage/spend, delivery workflow events (merged PRs), and compensation data. The 'intelligence cost of a PR' is a data-architecture artifact, not a spreadsheet artifact.

Why it matters

Most AI observability stacks stop at per-request token accounting. The insight implies the cost surface belongs one layer up, at the join of LLM telemetry with business process events and identity, which is what makes the analysis possible at all.

Generalization

AI cost observability is only decision-useful when correlated with a downstream outcome event and a human-cost denominator; per-call token accounting alone cannot answer ROI questions.

Combines human salary spend and AI spend into a single cost bucket to evaluate the true unit cost of merged code.
Open source video
Track total intelligence cost (human + artificial) per PR every month.
Open source video
Mechanismmedium noveltyweak evidence

Token spend scales roughly an order of magnitude across the population (lightest quintile ~60M tokens/dev/month vs heaviest ~2.5B), meaning the variance in AI usage behavior across a real organization is enormous — a single default model/routing/context policy cannot be near-optimal for both ends.

Why it matters

If consumption varies by ~1-2 orders of magnitude between cohorts, then design choices about context window sizes, tool-call budgets, retrieval depth, and agent step limits are not marginal tunings but tier-defining decisions. It argues for usage-tiered harness configurations rather than one global configuration.

Generalization

In deployed agent platforms, resource consumption is heavy-tailed across users; harness budgets should be parameterized per tier/user rather than fixed globally.

Lightest token spenders use ~60M tokens/dev/month; heaviest spenders use ~2.5B tokens/dev/month (8x more tokens).
Open source video

Deep dives

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Saturation point of the token-spend dose-response curve

Research question

If token spend per developer is swept continuously from ~60M to ~2.5B per month, at what point does marginal PR throughput gain stop compensating for marginal AI spend, and does blended cost per merged PR have an interior minimum?

Why

The reported result only compares quintile endpoints and reports monotone improvement at the heaviest bucket; without curve shape there is no defensible basis for setting budgets, and a plateau or reversal would convert 'spend more' from a finding into a bounded policy.

The heaviest fifth of token spenders saw a 67% increase in PR throughput.
Open source video
Cost per PR fell for all groups, but the heaviest fifth saw a 32% decrease in cost per PR.
Open source video
Lightest token spenders use ~60M tokens/dev/month; heaviest spenders use ~2.5B tokens/dev/month (8x more tokens).
Open source video
Source video

Causal identification for the heavy-spend throughput advantage

Research question

Does raising token/tool budgets for a matched cohort of developers cause an increase in accepted artifacts per human review cycle, or does the quintile split merely select teams that were already shipping faster?

Why

The entire governance recommendation (loosen token caps, optimize throughput) rests on a cross-sectional observational split; if selection explains the 67%/32% figures, the prescription actively misallocates budget by rewarding already-high-performing teams.

AI spend inflection points correlate with steady increases in throughput gains.
Open source video
Merged PRs per engineer are up 43% over the same period.
Open source video
The heaviest fifth of token spenders saw a 67% increase in PR throughput.
Open source video
Source video

Guardrail placement: protect human attention rather than token budgets

Research question

For an agent harness, does a budget policy that caps human review iterations per merged change dominate a policy that caps tokens per request, on blended cost per accepted artifact?

Why

If salary is the dominant cost term, then token caps protect the small line item while leaving the large one unmanaged; this reframes reliability engineering targets from per-call cost to human touches per accepted artifact, which requires different instrumentation entirely.

AI represents about 2.5% of the cost to produce a unit of merged code.
Open source video
Salary represents the other 97.5%.
Open source video
Tokens are the cheap part of producing software.
Open source video
Source video

Identity-join architecture for blended unit economics

Research question

What minimum join keys and event contracts are required to reliably attribute merged artifacts to agent sessions and to a loaded human cost, and how much of the metric is lost when any one plane is missing?

Why

The headline metric is a data-architecture artifact spanning three siloed telemetry planes; most stacks stop at gateway token accounting, so the practical question is what identity resolution must exist before any ROI claim is computable at all.

Combines human salary spend and AI spend into a single cost bucket to evaluate the true unit cost of merged code.
Open source video
Track total intelligence cost (human + artificial) per PR every month.
Open source video
Source video

Article ideas

4

Your Token Bill Is 2.5% of the Problem

Teams that instrument and optimize inference spend are optimizing the wrong line item: in a blended cost-per-merged-PR model, AI is a rounding error next to salary, so token-efficiency work can be locally successful and globally negative-value while interventions that raise artifacts per human cycle capture almost all the leverage.

Angle

Take the 2.5%/97.5% split seriously and walk through what it invalidates — per-call cost dashboards, request-level rate limits, model-routing micro-optimizations — then specify the metric that should replace them.

Source video

A 60x Cost Increase That Lowered Unit Cost

A 60x rise in AI spend per PR coexisting with falling total cost per PR is not a paradox but arithmetic: when the dominant cost is quasi-fixed salary, any intervention that raises shipped artifacts per person swamps order-of-magnitude growth in the marginal cost term, which means 'spend growth' is the wrong budget alarm and 'artifacts per human cycle' is the right one.

Angle

Decompose the ratio into numerator and denominator, show why finance intuition fails on fixed-cost amortization, and give the sensitivity test leaders should run before cutting AI budgets.

Source video

Stop Throttling Your Best Users

Blanket token caps are a governance default that suppresses exactly the cohort with the best unit economics: cohorting by consumption quintile turns a raw spend dashboard into a dose-response curve, and that curve argues for usage-tiered budgets rather than one global limit.

Angle

Contrast aggregate spend reporting with quintile outcome-per-cost reporting, and show how a single global cap conflates a runaway loop with a high-throughput power user.

Source video

Cost Observability Lives One Layer Too Low

Per-request token accounting cannot answer ROI questions because the decision-useful cost surface is the join of inference telemetry, workflow acceptance events, and human cost; until agent sessions are resolvable to a person and an accepted artifact, every AI cost dashboard is a billing artifact masquerading as an economics tool.

Angle

Specify the event contracts and identity keys required for the join, and show which questions become unanswerable when the join is absent.

Source video

Project ideas

4

Blended Unit-Cost Joiner

gatehouse

A pipeline joining inference telemetry, acceptance events, and loaded human cost produces a cost-per-accepted-artifact number whose rank ordering of teams differs materially from a token-spend ranking, and whose variance is dominated by the artifact-count denominator rather than the AI-spend numerator.

Proof of concept

Ingest gateway token logs, VCS merge events, and synthetic compensation bands; resolve agent session to developer to merged change; emit daily blended cost per accepted artifact with a numerator/denominator variance decomposition. Run on 6 months of backfilled data and compare team rankings under blended cost versus token spend.

Measurement

Spearman rank correlation between token-spend ranking and blended cost-per-artifact ranking (hypothesis: weak or negative); share of cost-per-artifact variance attributable to denominator movement; percentage of agent sessions successfully joined to an accepted artifact.

Source video

Budget-Raising Rollout Trial

movement-lab

Raising context, tool-call, and step budgets for a matched cohort raises accepted artifacts per human review cycle enough that blended cost per accepted artifact does not increase, and the effect is not explained by pre-existing team velocity.

Proof of concept

Staged enablement: randomly assign teams to raise harness budgets at staggered dates; measure reviewed-and-merged changes per developer-week and human review iterations per accepted change before and after each switch, with a matched holdout.

Measurement

Pre/post change in accepted artifacts per developer-week and in human touches per accepted artifact; blended cost per accepted artifact; test for pre-trend differences between treated and holdout to separate effect from selection.

Source video

Human-Touch Budget Harness

beyond-evals

Capping human review iterations and rework loops per accepted change reduces blended cost per artifact more than an equivalent tightening of token budgets, because human touches carry the dominant cost weight.

Proof of concept

Instrument an agent harness to count human interventions, review round-trips, and rework cycles per candidate change; run two policies against the same task stream — token caps versus touch caps — and compare blended cost per accepted artifact at equal acceptance quality.

Measurement

Human touches per accepted artifact, acceptance rate, and blended cost per accepted artifact under each policy; sensitivity of total cost to a 10x token-cost change versus a 10% change in touches per artifact.

Source video

Quintile Dose-Response Dashboard

new

Bucketing users or agents into consumption deciles and reporting outcome-per-cost per bucket reveals an interior saturation point that a single aggregate spend number conceals, and the saturation point differs by workflow tier.

Proof of concept

Build a reporting layer over existing telemetry that plots throughput gain and cost per accepted artifact against continuous spend deciles (p10/p50/p90/p99 rather than quintile labels), and check whether the reported spread is consistent with per-developer versus per-org aggregation.

Measurement

Curve shape and location of any plateau or inflection; consistency of the spend spread across aggregation levels; number of teams whose optimal budget recommendation differs under deciles versus quintiles.

Source video

Architectural implications

3

The decision-relevant metric joins LLM telemetry, workflow events, and salary data rather than living in the inference gateway.

Before

Cost observability is implemented at the model gateway as per-request token and dollar accounting, owned by the platform team.

After

A blended unit-economics pipeline joins developer identity, token usage, and merged-artifact events into a single cost-per-artifact surface, consumed by engineering leadership.

Consequence

Identity resolution across systems (agent sessions ↔ developer ↔ PR) becomes a first-class infrastructure requirement, and cost dashboards become a product surface rather than a billing artifact.

Source video

If human cycles dominate unit cost, the scarce resource that guardrails should protect is human attention, not tokens.

Before

Rate limits, token caps, and spend alerts are placed on the model/inference layer as the primary cost control.

After

Guardrails target the human-in-the-loop stages — review cycles, rework loops, and human interventions per merged change — with token limits serving only as a runaway-loop safety backstop.

Consequence

Agent runtime design shifts toward reducing human review iterations per accepted artifact; token budgets get loosened, and instrumentation for 'human touches per PR' becomes the primary reliability metric.

Source video

Throughput, not spend, drives unit cost in the reported data.

Before

Agents are optimized and benchmarked against per-task cost or per-call latency.

After

Agents are evaluated on accepted artifacts per unit of human time, with cost treated as a nearly free input within a wide band.

Consequence

Evaluation harnesses need to model end-to-end cycle time including human review, which is far harder to instrument than token counts and requires workflow-level, not request-level, tracing.

Source video

Tradeoffs and failure modes

4

Token throttling as a governance default

Benefit

Directly caps a cost line that grew 60x and satisfies short-term budget pressure.

Cost or risk

Suppresses the usage cohort that shows the largest throughput gain and lowest cost per PR, sacrificing salary amortization to protect a cost line described as a small fraction of unit cost.

Do not let AI token spend be the primary driving metric for engineering efficiency.
Open source video
Source video

Observational cohort comparison vs causal attribution

Benefit

Quintile analysis over a year of telemetry is feasible on existing data without controlled experiments.

Cost or risk

Heavy token spenders may be confounded with already-strong teams or different task mixes, so the 67%/32% figures may partly reflect selection rather than an effect of more tokens.

Cost per PR changes are driven largely by PR throughput, not by AI spend.
Open source video
Source video

Merged PRs as the throughput denominator

Benefit

Merged PRs are a countable, already-instrumented workflow event that enables a per-artifact cost metric.

Cost or risk

Any productivity metric attached to a reward becomes a target; PR count is a proxy that can be inflated by splitting work, so unit-cost improvements could be manufactured without real delivery gain.

Merged PRs per engineer are up 43% over the same period.
Open source video
Source video

Blending human and machine spend into one bucket

Benefit

Produces a single comparable unit cost and prevents optimizing a small line item in isolation.

Cost or risk

Salary data is sensitive, org-specific, and rarely joinable to per-request telemetry; the blended metric may be computable only for organizations with mature identity and HR data, and averages can hide per-team divergence.

AI represents about 2.5% of the cost to produce a unit of merged code.
Open source video
Source video

Open questions

4

Where does the token-spend dose-response curve saturate or turn negative?

Why unresolved

The summary reports gains at the heaviest quintile (~2.5B tokens/dev/month) but gives no curve shape and lists 'diminishing returns' only as terminology, not as a measured result.

Research direction

Plot throughput gain and cost per PR against continuous token-spend deciles rather than quintiles, and look for an inflection or plateau; test whether above some spend level throughput gains stop compensating for added cost.

Source video

Is the heavy-token-spend advantage causal or a selection effect?

Why unresolved

The evidence is a cross-sectional quintile split over observational telemetry; teams that already ship more may simply be the ones that adopted AI more aggressively.

Research direction

Within-team longitudinal analysis around adoption inflection points, or a staged enablement rollout (raising token/tool budgets for a matched subset) measuring throughput before and after.

Source video

Does the pattern transfer to non-PR workflows, such as agents operating in ops, support, or research pipelines?

Why unresolved

Every reported metric is anchored to merged pull requests, a code-specific artifact with a review gate and a merge event.

Research direction

Define analogous 'accepted artifact' events in non-code domains (tickets resolved, incidents closed, analyses accepted) and repeat the blended-intelligence-cost analysis to see whether the 2.5%/97.5% split and throughput mechanism generalize.

Source video

Is the reported token-spend spread internally consistent, and what does it imply about tiering?

Why unresolved

The summary cites ~60M vs ~2.5B tokens per developer per month but labels the ratio '8x more tokens', which does not match the stated figures; the true spread affects how aggressively harness configurations should be tiered.

Research direction

Re-derive the distribution from the raw telemetry, report percentiles (p10/p50/p90/p99) rather than quintile labels, and check whether per-developer vs per-company aggregation explains the discrepancy.

Source video

Key claims

6
factualVerification needed

AI spend per merged PR increased 60x between September and August of the study window.

Evidence

AI spend per PR is up 60x over the past year.

Question

Does the 60x figure hold per-company and in median terms, or is it driven by a small set of heavy adopters and changing model pricing?

Source video
comparativeVerification needed

AI accounts for only ~2.5% of the cost of a merged PR, with developer salary at 97.5%.

Evidence

AI accounts for 2.5% of the cost of a merged PR while salary accounts for 97.5%.

Question

How is fully-loaded salary allocated to PRs, and does the split hold for low-salary regions or high-inference-cost workloads such as long-running agent fleets?

Source video
causalVerification needed

The heaviest token-spending quintile achieved 67% higher PR throughput and 32% lower cost per PR.

Evidence

Heaviest token spenders achieved a 67% increase in PR throughput and 32% decrease in cost per PR.

Question

Is the gain attributable to token spend, or confounded with team composition, task type, or pre-existing adoption maturity?

Source video
causalVerification needed

Changes in cost per PR are driven primarily by PR throughput rather than by AI spend.

Evidence

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

Question

What is the sensitivity of cost per PR to a 10x change in AI spend versus a 10% change in throughput, holding team and task mix constant?

Source video
causalVerification needed

Merged PRs per engineer rose 43% over the year, and AI spend inflection points correlate with subsequent throughput gains.

Evidence

AI spend inflection points correlate with steady increases in throughput gains.

Question

Do throughput gains lag spend inflection points consistently across organizations, or does adoption timing vary enough to make the correlation accidental?

Source video
factualVerification needed

Total blended intelligence cost per PR fell 26% over the year despite the 60x rise in AI spend.

Evidence

Total intelligence cost per PR fell 26% over the year.

Question

Is the 26% decline robust to salary inflation, headcount mix changes, and PR-size normalization over the same period?

Source video

Connections

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