claude-sonnet
Claude Sonnet — Balanced Implementation Tier
Concept of the skill
What it is: claude-sonnet is the routing decision for a model provider's balanced middle tier — the default lane for ordinary implementation work that sits between the frontier reasoning tier and the fast/cheap tier on both cost and capability.
Mental model: A model roster is a tiered ladder. The middle rung is the default — routing starts here and moves only with evidence: up to the frontier tier when a task proves too hard, down to the fast tier when a task proves mechanical. Most work clears the middle rung at lower cost and latency than the top.
Why it exists: Without an explicit "default lane," routing collapses into one of two bad habits — sending everything to the smartest model (overpaying) or chasing the cheapest (underperforming on real coding work). A named balanced tier anchors the roster: it is where work goes unless there is a specific reason to escalate or drop.
What it is NOT: It is not the tier for the hardest reasoning (that earns the frontier tier) nor for high-volume mechanical work (that drops to the fast tier or a script). It is not a quality compromise — for well-specified feature work it is the correct choice, not a budget concession.
Adjacent concepts: the frontier reasoning tier (escalation target for hard tasks); the fast/cheap tier (drop target for mechanical/high-volume work); cost-aware delegation (the policy that decides which way to move off the default); loop architecture (the harness the model runs inside).
One-line analogy: The balanced tier is the experienced generalist who handles the bulk of the caseload well — you escalate to the specialist only for the genuinely hard case and hand the routine paperwork to the assistant.
Common misconception: That the middle tier is "the cheaper compromise you settle for." It is not a compromise — it is the default, chosen affirmatively because most implementation work does not need the frontier tier's ceiling and is poorly served by the fast tier's limits.