Skip to content

agent-model-tier-rubric

Agent Model Tier Rubric — Ban model: inherit, Pin Explicit Tiers

Section titled “Agent Model Tier Rubric — Ban model: inherit, Pin Explicit Tiers”

Status: kit-wide, decision-authority rule for every TheOneKit kit. Resolves core#339.

Every kit-shipped agent ($HOME/.claude/agents/*.md, and any modules/*/agents/*.md) MUST declare an explicit model: tier — one of opus, sonnet, or haiku. model: inherit (or a missing model:) is banned: it’s a bug, filed against the owning kit (/t1k:issue) and fixed at the kit source — never silently patched in a consumer.

inherit defers to the parent’s model under transparent routing, so quality/cost become caller-dependent (opus work silently degrades from a cheap parent; cheap work wastes Opus from an opus orchestrator). The pinned tier is also the routing key the interceptor maps via modelMapping; opus is a quality assertion that is never cheap-routed.

TierWhen to useExample agents
opusReasoning / orchestration / planning / architecture / adversarial-review / decision work — judgment-heavy, cross-domain, or quality-sensitive.planner, architect, brainstormer, project-manager, code-reviewer, debugger, researcher, predict
sonnetImplementation / authoring — focused feature work, checklist-driven review, content authoring.fullstack-developer, kit-developer, skills-manager, docs-manager, agent-creator, skill-creator, engine developers, ui developers
haikuMechanical / narrow — deterministic workflows, running suites, simple exploration, formatting, mechanical sweeps.tester (running suites), simple explorers, formatters, git-manager (commit/push), code-simplifier (mechanical), mcp-manager

Tie-break: when genuinely ambiguous between two tiers, default to sonnet — never under-tier quality-sensitive work; reserve haiku for unambiguously mechanical work.

Why inherit is banned (quality/cost bleed), the audit/apply procedure, enforcement points (t1k-agent-creator, t1k-doctor, CI gate), and history (#339): docs/agent-model-tier-rubric.md.

  • rules/mr-transparent-routing.md — pinned tier → routing key; opus passthrough.
  • rules/naming-convention.md — the parallel t1k- prefix mandate.
  • core#339 — originating decision.