llm-model-selection

llm-model-selection is a skill for Claude Code, Codex from fabioc-aloha/Alex_Skill_Mall. It costs 21 tokens per session (2,199 once invoked), scanned A, original, MIT.

A guide for choosing a large language model based on the task, response quality, speed, and cost.

In plain words
What is it for?
Use it to compare model families, match models to agent tasks, and account for changing model capabilities, prices, and availability.
Why use it?
It helps prevent using an unnecessarily expensive model for simple work or choosing a weaker model for tasks that need more reasoning.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: positional $N argument; mentions Codex.

Good fit Use it to compare model families, match models to agent tasks, and account for changing model capabilities, prices, and availability.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/fabioc-aloha/alex_skill_mall/llm-model-selection
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add fabioc-aloha/Alex_Skill_Mall --skill llm-model-selection
Clone the repo
git clone --depth 1 https://github.com/fabioc-aloha/Alex_Skill_Mall

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for llm-model-selection

README.md
[![agentmods](https://agentmods.dev/badge/skills/fabioc-aloha/alex_skill_mall/llm-model-selection/github.svg)](https://agentmods.dev/skills/fabioc-aloha/alex_skill_mall/llm-model-selection)
Your own site
<a href="https://agentmods.dev/skills/fabioc-aloha/alex_skill_mall/llm-model-selection"><img src="https://agentmods.dev/badge/skills/fabioc-aloha/alex_skill_mall/llm-model-selection/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for llm-model-selection

Your own site · 80×15
<a href="https://agentmods.dev/skills/fabioc-aloha/alex_skill_mall/llm-model-selection"><img src="https://agentmods.dev/badge/skills/fabioc-aloha/alex_skill_mall/llm-model-selection.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 21 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,199 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00021 $0.02199
Opus 5 $0.00010 $0.01099
Sonnet 5 $0.00004 $0.00440
Haiku 4.5 $0.00002 $0.00220

Measured 8d ago against content hash bbe8fbebd9cd, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

llm-model-selection scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

plugins/ai-agents/llm-model-selection/skills/llm-model-selection/SKILL.md · 218 lines

How it starts

The opening of the file, as written. The whole thing — 218 lines — stays where its author put it; the contents beside it link to each section on GitHub.

LLM Model Selection Skill

Choosing the right model for the task — power vs. cost vs. speed.

⚠️ Staleness Warning

This skill depends on rapidly evolving technology. Model capabilities, pricing, and availability change frequently.

Refresh triggers:

  • New model announcements (Claude, GPT, Gemini, etc.)
  • Significant pricing changes
  • Context window expansions
  • New capability tiers

Last validated: March 2026 (Claude 4.6 generation)

Check current state: Anthropic Models, OpenAI Models


The Core Question

Is Claude Opus 4.6 overkill?

Sometimes yes, sometimes no. Match the model to the task.

Claude 4 Model Family (Current)

Model API ID Best For Input/Output (MTok) Context Max Output
Opus 4.6 claude-opus-4-6 Building agents, most intelligent $5 / $25 200K (1M beta) 128K
Sonnet 4.6 claude-sonnet-4-6 Best speed + intelligence balance $3 / $15 200K (1M beta) 64K
Haiku 4.5 claude-haiku-4-5-20251001 Near-frontier intelligence, fastest $1 / $5 200K 64K

All Claude 4 models support:

  • Extended thinking
  • Vision (images)
  • Tool use
  • Priority Tier access

Opus 4.6 and Sonnet 4.6 additionally support:

  • Adaptive thinking (dynamic reasoning depth)
  • 1M token context window (beta, via context-1m-2025-08-07 header — long context pricing applies beyond 200K)

AWS Bedrock IDs: anthropic.claude-opus-4-6-v1, anthropic.claude-sonnet-4-6 GCP Vertex AI IDs: claude-opus-4-6, claude-sonnet-4-6

Model Tiers

Tier Models Best For Relative Cost
Frontier Claude Opus 4.6, GPT-5.2/5.3/Codex, o3, o1-pro Complex reasoning, architecture, novel problems $$$$$
Capable Claude Sonnet 4.6, GPT-5.1/Codex, GPT-4.1, GPT-4o, Gemini 2.5/3 Pro, o4-mini Most coding tasks, refactoring, debugging $$$
Efficient Claude Haiku 4.5, GPT-5 mini, GPT-4.1 mini/nano, GPT-4o mini, Gemini 2.5 Flash, Gemini 3 Flash Simple edits, formatting, boilerplate $

Read the full file on GitHub · 218 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 218 lines · 21 tokens per session scan A bbe8fbebd9cd

Subscribe to this mod's changes

llm-model-selection is a skill published in the GitHub repository fabioc-aloha/Alex_Skill_Mall (4 stars, last pushed today), licensed MIT. It adds 21 tokens to every session and 2,199 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.

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