A platform that routes all inference work through the highest-capability model available regardless of work shape spends significantly more per output than necessary. A platform with no guidance on model selection leaves each contributor to make independent choices that may be inconsistent, cost-inefficient, or both. Model tier discipline is the structured approach that matches work shape to model capability, routes appropriate work to lower-cost tiers, and makes the routing decision explicit and reviewable.

Three abstract tiers

Work shapes fall into three categories that map to three model tiers:

Deep-think. Architectural decisions, doctrine authoring, cross-cutting analysis, novel problem framing, multi-source synthesis. These are the tasks where a more capable model's additional reasoning ability produces materially better outputs. Examples: authoring a new convention, debugging a problem whose root cause is not yet identified, coordinating decisions across multiple workstreams.

Implementation. Following an established plan, single-component scoped work, well-specified feature implementation, code review against ratified conventions. A model at this tier can produce correct output on an established specification without needing the full reasoning capacity required for deep-think work. Examples: scaffolding a new module from a documented spec, drafting a runbook from a known template, writing unit tests for a defined interface.

Mechanical. Pattern-matching work with clear inputs and outputs, no architectural judgment, repeatable structure. The work is correct or incorrect in an unambiguous way. Examples: file moves, version number bumps, registry row updates, formatting normalization.

The preferred in-seat routing mechanism

When a work session reaches a natural pause and the next bounded chunk of work fits a lower tier, the session dispatches a foreground sub-agent at the appropriate tier rather than continuing to perform that work at the current tier. The parent session retains its context and waits for the sub-agent to complete, then reviews the result and either commits it or queues the next chunk.

This approach preserves session context while routing volume work through lower-cost tiers. The parent pays parent-tier rates only for orchestration — reviewing results, authoring commit messages, making the next structural decision. The sub-agent does the volume work at a lower rate.

Four properties govern how sub-agent dispatch works in practice:

Bounded brief. One task, one result, self-contained. The brief includes file paths, names the desired output shape, and caps response length. Open-ended exploration is not a sub-agent task.

Foreground and serial when writing. A sub-agent writing to files runs to completion before the next one starts. Parallel dispatch is appropriate for read-only work — research, scanning, triage — but not for write operations that share a file index.

Confidence gate. Dispatch only when there is high confidence the sub-agent will produce output matching or exceeding what the current tier would produce on the same bounded task. Mechanical edits, well-specified implementations, read-only research, and scoped refactors against a clear spec pass this gate. Architectural decisions, doctrine drafting, cross-layer coordination, and anything requiring novel framing do not.

Layer scope preserved. A sub-agent dispatched from one layer operates within that layer's scope. Cross-layer work travels through the established coordination mechanism rather than through sub-agent dispatch.

The cost framing

The three-tier structure produces a significant effective multiplier at fixed daily token budgets. Using the same daily token cap, running mechanical work at the mechanical tier instead of the deep-think tier extends the budget by approximately a factor of fifteen. A contributor pool operating at tier discipline can sustain a substantially larger volume of committed output within the same infrastructure cost as a smaller pool operating without tier discipline.

This multiplier is the structural reason why a contributor model that includes a larger pool of paid contributors is operationally viable. Without tier discipline, that model is expensive enough to be impractical. With it, the cost structure works.

What the discipline is not

Model tier discipline does not refuse work at the current tier. Sessions write a dispatch recommendation or proposal; a human principal decides whether to act on it. The discipline is a cost-optimization recommendation mechanism, not a gate.

It is also not a constant check. Recommendations fire only at substantive work-shape pivots. Constant suggestions create overhead that erodes the cost savings they are intended to produce. The trigger is a genuine pivot, not a micro-pause.

Tier discipline and model version progression are orthogonal axes. A new model version earning a role through a supervised period of demonstrated correctness is a different question from which tier of the current model family to use for a specific bounded task. Both apply simultaneously.

See also

• compounding-substrate — the contributor model this discipline makes economically viable