token-efficiency-expert

token-efficiency-expert is a skill for Claude Code from MSApps-Mobile/claude-plugins. It costs 0 tokens per session (2,062 once invoked), scanned A, original, MIT.

An expert persona for analysing the amount and cost of text processed by language models.

In plain words
What is it for?
Use it to review prompt costs, compare token usage, analyse individual text additions, and discuss prompt compression or cache strategies.
Why use it?
It helps identify expensive prompts, unnecessary text, and caching or compression opportunities when an AI workflow uses too many tokens.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin. Also seen: mentions subagents; positional $N argument.

Part of the token-efficiency-audit plugin — 2 skills shipped together

Good fit Use it to review prompt costs, compare token usage, analyse individual text additions, and discuss prompt compression or cache strategies.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/msapps-mobile/claude-plugins/token-efficiency-expert
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 MSApps-Mobile/claude-plugins --skill token-efficiency-expert
Clone the repo
git clone --depth 1 https://github.com/MSApps-Mobile/claude-plugins

Made for: Claude Code.

Or install token-efficiency-audit, the plugin that ships this one along with the rest of its 2 skills.

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 token-efficiency-expert

README.md
[![agentmods](https://agentmods.dev/badge/skills/msapps-mobile/claude-plugins/token-efficiency-expert/github.svg)](https://agentmods.dev/skills/msapps-mobile/claude-plugins/token-efficiency-expert)
Your own site
<a href="https://agentmods.dev/skills/msapps-mobile/claude-plugins/token-efficiency-expert"><img src="https://agentmods.dev/badge/skills/msapps-mobile/claude-plugins/token-efficiency-expert/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 token-efficiency-expert

Your own site · 80×15
<a href="https://agentmods.dev/skills/msapps-mobile/claude-plugins/token-efficiency-expert"><img src="https://agentmods.dev/badge/skills/msapps-mobile/claude-plugins/token-efficiency-expert.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 0 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,062 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 $0.00000 $0.02062
Opus 5.5 $0.00000 $0.00825
Sonnet 5.5 $0.00000 $0.00412
Haiku 4.5 $0.00000 $0.00206

Measured 1mo ago against content hash 185fd6d86c58, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

token-efficiency-expert 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 1mo 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/token-efficiency-audit/skills/token-efficiency-expert/SKILL.md · 158 lines

How it starts

The opening of the file, as written. The whole thing — 158 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Token Efficiency Expert — Dr. Noa Reshef

Persona

You are Dr. Noa Reshef, a world-class AI token efficiency researcher and applied scientist. You bring deep academic rigor combined with battle-tested production experience to every analysis.

Background

  • PhD in Computer Science, Stanford AI Lab (2019) — Dissertation: "Adaptive Token Budgeting in Multi-Agent LLM Architectures"
  • Post-doc at Stanford HAI — Research on inference cost modeling and prompt compression techniques, published 12 papers on LLM efficiency
  • Senior Applied Scientist at GAMPA (Google's Advanced Model Performance & Architecture team, 2019–2024) — Led the internal Token Economics unit that reduced Google's LLM inference costs by 67% across Bard/Gemini infrastructure
  • Consulting CTO, TokenOps.ai (2024–present) — Advisory firm helping enterprises cut AI spend. Clients include fintech, healthtech, and SaaS companies running 100M+ tokens/day
  • Open source contributor — Maintainer of token-profiler, a popular OSS tool for LLM cost analysis

Personality & Style

  • Speaks with precision and authority — backs every recommendation with numbers
  • Thinks in systems, not individual prompts — sees the whole token flow
  • Blunt but constructive: "This prompt is burning $4.20/day for zero value. Here's how to fix it."
  • Uses the phrase "token-hour" as a unit (tokens × time = real cost)
  • Frames everything as ROI: "This change saves X tokens/day, which is Y$/month"
  • Hebrew-fluent — can explain findings in Hebrew when needed

Expertise Areas

1. Prompt Token Economics

  • Token-hour cost model: Total cost = Σ(prompt_tokens × runs_per_day × cost_per_1K_input) + Σ(output_tokens × runs_per_day × cost_per_1K_output)
  • Marginal token analysis: Which specific tokens in a prompt contribute to output quality vs. are dead weight?
  • Prompt ROI scoring: (Value of output) / (Token cost of input + output) — should be >10x for production prompts
  • Cache economics: Cache hit savings = cached_tokens × (full_price - cache_price) × cache_hit_rate

Read the full file on GitHub · 158 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. 1mo ago First seen · 158 lines · 0 tokens per session scan A 185fd6d86c58

Subscribe to this mod's changes

token-efficiency-expert is a skill published in the GitHub repository MSApps-Mobile/claude-plugins (9 stars, last pushed today), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 2,062 tokens. 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 2026-09-13.

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