modernize-move

modernize-move is a skill for Claude Code from aptos-labs/aptos-agent-skills. It costs 60 tokens per session (2,703 once invoked), scanned A, original, MIT.

A review and upgrade guide for old Move V1 smart-contract code to newer Move V2 syntax, patterns, and APIs. It requires analysis and tests before and during the changes.

In plain words
What is it for?
Use it when migrating an existing Move V1 contract to Move V2 or replacing outdated Move APIs and coding patterns.
Why use it?
It helps update legacy contracts while checking that their behaviour remains correct after each group of changes.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: names the AskUserQuestion tool.

Part of the aptos-agent-skills plugin — 16 skills shipped together

Good fit Use it when migrating an existing Move V1 contract to Move V2 or replacing outdated Move APIs and coding patterns.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/aptos-labs/aptos-agent-skills/modernize-move
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 aptos-labs/aptos-agent-skills --skill modernize-move
Clone the repo
git clone --depth 1 https://github.com/aptos-labs/aptos-agent-skills

Made for: Claude Code.

Or install aptos-agent-skills, the plugin that ships this one along with the rest of its 16 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 modernize-move

README.md
[![agentmods](https://agentmods.dev/badge/skills/aptos-labs/aptos-agent-skills/modernize-move/github.svg)](https://agentmods.dev/skills/aptos-labs/aptos-agent-skills/modernize-move)
Your own site
<a href="https://agentmods.dev/skills/aptos-labs/aptos-agent-skills/modernize-move"><img src="https://agentmods.dev/badge/skills/aptos-labs/aptos-agent-skills/modernize-move/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 modernize-move

Your own site · 80×15
<a href="https://agentmods.dev/skills/aptos-labs/aptos-agent-skills/modernize-move"><img src="https://agentmods.dev/badge/skills/aptos-labs/aptos-agent-skills/modernize-move.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,703 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 $0.00060 $0.02703
Opus 5 $0.00030 $0.01352
Sonnet 5 $0.00012 $0.00541
Haiku 4.5 $0.00006 $0.00270

Measured 10d ago against content hash bee27b91fb32, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

modernize-move 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 10d 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.

skills/move/modernize-move/SKILL.md · 247 lines

How it starts

The opening of the file, as written. The whole thing — 247 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Skill: modernize-move

Detect and modernize outdated Move V1 syntax, patterns, and APIs to Move V2+. Preserves correctness through tiered transformations with test verification after each tier.

Essential Principles

Five non-negotiable rules for every modernization:

  1. Test safety net is mandatory WHY: Modernization must preserve behavior. No tests = no safety net. If no tests exist, invoke generate-tests skill first to create comprehensive tests before making any changes.

  2. Analyze before modifying WHY: The user must see exactly what will change and confirm the scope. Never surprise-edit code. Present the full analysis report and wait for confirmation.

  3. Tiered execution order WHY: Syntax changes (Tier 1) are zero-risk. API migrations (Tier 3) change semantics. Always apply safest changes first so riskier changes build on a clean, verified foundation.

  4. Verify after each tier WHY: If tests break, you know exactly which tier caused it. Revert that tier and investigate before proceeding. Never apply the next tier on a broken baseline.

  5. Preserve error code values WHY: Tests use #[expected_failure(abort_code = N)]. Changing numeric values breaks tests silently. When creating named constants, the numeric value MUST match the original literal.

When to Use This Skill

  • Upgrading Move V1 contracts to V2 syntax
  • Migrating public(friend) to package fun
  • Converting vector::borrow to index notation
  • Converting while loops with counters to for range loops
  • Replacing manual vector iteration with stdlib inline functions (vector::for_each_ref, vector::map, vector::fold, etc.) and lambdas
  • Replacing magic abort numbers with named constants
  • Migrating legacy coin/TokenV1 to modern fungible_asset/Digital Assets
  • Converting EventHandle to #[event] pattern
  • Upgrading custom signed integer workarounds to native i8-i256 types

When NOT to Use This Skill

  • Writing new contracts from scratch — use write-contracts
  • Fixing bugs or adding features — modernization is structural, not functional
  • Optimizing gas usage — use analyze-gas-optimization
  • Auditing security — use security-audit (run AFTER modernization)

Read the full file on GitHub · 247 lines

Files

What ships with it

2 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. 10d ago First seen · 247 lines · 60 tokens per session scan A bee27b91fb32

Subscribe to this mod's changes

modernize-move is a skill published in the GitHub repository aptos-labs/aptos-agent-skills (19 stars, last pushed 2mo ago), licensed MIT. It adds 60 tokens to every session and 2,703 once invoked, about $0.0003 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 2026-08-30.

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