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The tokenmaxxing proxy for model quality collapsed when agent deployments proved that cost per outcome is the binding constraint, not capability per call.

By Simon Willison · Independent developer, co-creator of Django, creator of Datasette; technology journalist and blogger at simonwillison.net · 2026-09-27 · essay · 2026 in LLMs (so far)

Tier B · TL;DR
The tokenmaxxing proxy for model quality collapsed when agent deployments proved that cost per outcome is the binding constraint, not capability per call.

Claim

Evaluating model quality by token-count output (tokenmaxxing) became a misleading heuristic once real agent deployments revealed that chained inference across multi-step tasks multiplies per-token costs to a scale where cost-per-outcome is the actual constraint, not raw model capability.

Mechanism

Tokenmaxxing assumed that models generating more tokens per response were higher-quality reasoners. In single-call evaluations, that correlated with reasoning depth. In agentic workflows, each task step is a separate inference call. A 30-step agent task multiplies the per-call cost by 30. At frontier model prices, that arithmetic makes high-token-count behavior a cost liability rather than a quality signal. The dominant constraint shifts from "which model is most capable per call" to "which model completes the task at an acceptable total cost." Willison observed this directly: real deployments of agents hit expensive ceilings that benchmark-pass-rate comparisons never surfaced.

Conditions

Holds when: agent tasks require many sequential model calls at frontier prices; the task completion cost scales with per-step token count.

Fails when: tasks are single-call or very short chains; cached intermediate outputs flatten the cost curve; sub-frontier models are already in use and token count was never the bottleneck.

Evidence

Willison described the shift in his September 2026 year-in-review keynote at WeAreDevelopers World Congress North America, observing that after tokenmaxxing emerged as a trend in late 2025, real agent deployments corrected it:

"the agents are expensive"

The observation captures the corrective signal. The tokenmaxxing proxy held when agents were hypothetical. It broke when practitioners ran agents at scale and received billing surprises.

Signals

Counter-evidence

Some agentic tasks genuinely benefit from high-token reasoning at each step. Complex multi-constraint planning, adversarial review, and long-chain reasoning problems may justify the cost if they compress human review time. The critique of tokenmaxxing lands on tasks where token count measured verbosity rather than reasoning depth. For those tasks, the signal was always misleading; agents just made the cost of the mistake visible.

Cross-references

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