How do I install the Model Tiers skill?

Run npx skillmds@latest add xakki/model-tiers in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Model Tiers safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Model Tiers?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Model Tiers free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Model Tiers?

Xakki (@xakki) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Model Tiers by xakki — Agent Skill

Name: Model Tiers
Author: Xakki

Model Tiers

Map cheap, standard, and judgment work to resolved model slugs via AI_MODEL_*. Use to select a subagent tier, override defaults, or map mechanical, product-logic, and architecture work to models such as Haiku, Sonnet, and Opus.

Xakki Updated Sep 21, 2026

File contents

model-tiers — cheap / standard / judgment

Three cognitive tiers — skills and delegation rules name tiers only, never vendor model slugs. Resolved slugs for this session are injected at SessionStart (hooks/model-tiers-inject.sh) and appear in context as cheap, standard, judgment.

Tiers

Tier	Role	Default slug
cheap	Mechanical, spec-complete, single-pass work (grep, rename, format, inventory)	`haiku`
standard	Routine product logic, known patterns, doc/skill edits, code review	`sonnet`
judgment	Architecture, tricky debug, cross-file synthesis, multi-source research	`opus`

When torn between two tiers, pick the cheaper one; escalate on ambiguity. Floor = standard for anything touching product logic.

Env keys

Key	Tier
`AI_MODEL_CHEAP`	cheap
`AI_MODEL_STANDARD`	standard
`AI_MODEL_JUDGMENT`	judgment

Precedence

Runtime environment — AI_MODEL_* values inherited when the agent starts. Claude, Codex, and Cursor can set these through their settings.json env block. For Prime Agent, export them in the shell/service that starts prime-agent; use exact selectors accepted by prime-agent model list.
Plugin defaults — skills/model-tiers/defaults.env (shipped with the plugin).

Unset override keys fall back to defaults. Never invent a model — always use the resolved slug from the map above or from SessionStart injection.

SessionStart inject

Every session receives a tiny block:

## Model tiers (resolved for this session)
cheap = <slug>
standard = <slug>
judgment = <slug>

Pass these slugs as model: on every Agent / Task call. Omitting model: inherits the caller's tier (expensive default).

Configure overrides

Set AI_MODEL_* in the active runtime's environment. Claude, Codex, and Cursor can use their settings.json env block; for Prime Agent, export the values before startup. Long jq examples → reference.md.

Agent frontmatter limitation

YAML model: in .claude/agents/*.md is not env-expanded — frontmatter tracks plugin defaults at authoring time. Callers must pass the resolved slug from the tier map when invoking agents; skills reference tiers (cheap, standard, judgment) only.

---name: model-tiersdescription: Map cheap, standard, and judgment work to resolved model slugs via AI_MODEL_*. Use to select a subagent tier, override defaults, or map mechanical, product-logic, and architecture work to models such as Haiku, Sonnet, and Opus.---# model-tiers — cheap / standard / judgmentThree cognitive tiers — skills and delegation rules name **tiers only**, never vendormodel slugs. Resolved slugs for this session are injected at **SessionStart**(`hooks/model-tiers-inject.sh`) and appear in context as `cheap`, `standard`,`judgment`.## Tiers| Tier | Role | Default slug ||------|------|--------------|| **cheap** | Mechanical, spec-complete, single-pass work (grep, rename, format, inventory) | `haiku` || **standard** | Routine product logic, known patterns, doc/skill edits, code review | `sonnet` || **judgment** | Architecture, tricky debug, cross-file synthesis, multi-source research | `opus` |When torn between two tiers, pick the cheaper one; escalate on ambiguity. Floor =**standard** for anything touching product logic.## Env keys| Key | Tier ||-----|------|| `AI_MODEL_CHEAP` | cheap || `AI_MODEL_STANDARD` | standard || `AI_MODEL_JUDGMENT` | judgment |## Precedence1. **Runtime environment** — `AI_MODEL_*` values inherited when the agent starts. Claude, Codex, and Cursor can set these through their `settings.json` `env` block. For Prime Agent, export them in the shell/service that starts `prime-agent`; use exact selectors accepted by `prime-agent model list`.2. **Plugin defaults** — `skills/model-tiers/defaults.env` (shipped with the plugin).Unset override keys fall back to defaults. **Never invent a model** — always usethe resolved slug from the map above or from SessionStart injection.## SessionStart injectEvery session receives a tiny block:```## Model tiers (resolved for this session)cheap = <slug>standard = <slug>judgment = <slug>```Pass these slugs as `model:` on every `Agent` / `Task` call. Omitting `model:` inheritsthe caller's tier (expensive default).## Configure overridesSet `AI_MODEL_*` in the active runtime's environment. Claude, Codex, and Cursorcan use their `settings.json` `env` block; for Prime Agent, export the valuesbefore startup. Long jq examples → [reference.md](reference.md).## Agent frontmatter limitationYAML `model:` in `.claude/agents/*.md` is **not** env-expanded — frontmatter tracksplugin defaults at authoring time. Callers must pass the **resolved slug** from thetier map when invoking agents; skills reference tiers (`cheap`, `standard`,`judgment`) only.

Frequently asked questions