storage-migration

storage-migration is a skill for Claude Code, Codex from kaininx/PlainTab. It costs 63 tokens per session (663 once invoked), scanned A, original, MIT.

A safety checklist for changing PlainTab’s saved data, such as browser storage keys, database records, versions, backups, imports, and exports. A migration is the code that updates older saved data for a newer release.

In plain words
What is it for?
Use it before changing storage formats, version numbers, migration code, or cached wallpaper data. It guides focused migration checks and distinguishes database-structure changes from application-data changes.
Why use it?
It prevents upgrades from losing or misreading existing users’ data, including when someone jumps over several versions.

Skill for Claude CodeCodex

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.

agentmods
npx agentmods add skills/kaininx/plaintab/storage-migration
Any agent
npx skills add kaininx/PlainTab --skill storage-migration
Clone the repo
git clone --depth 1 https://github.com/kaininx/PlainTab

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 storage-migration

README.md
[![agentmods](https://agentmods.dev/badge/skills/kaininx/plaintab/storage-migration.svg)](https://agentmods.dev/skills/kaininx/plaintab/storage-migration)
Your own site
<a href="https://agentmods.dev/skills/kaininx/plaintab/storage-migration"><img src="https://agentmods.dev/badge/skills/kaininx/plaintab/storage-migration.svg" alt="Measured on agentmods" height="20"></a>
Per session 63 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 663 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00063 $0.00663
Opus 5 $0.00032 $0.00331
Sonnet 5 $0.00013 $0.00133
Haiku 4.5 $0.00006 $0.00066

Measured 4d ago against content hash edc28c19d9fb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

storage-migration 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 4d 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.

.agents/skills/storage-migration/SKILL.md · 57 lines

How it starts

The opening of the file, as written. The whole thing — 57 lines — stays where its author put it; the contents beside it link to each section on GitHub.

PlainTab Storage Migration

Use this skill as a red-line checklist for storage changes. User data safety and jump-upgrade behavior matter more than implementation neatness.

First Reads

  1. Read .claude/rules/00-core.md.
  2. Read .claude/rules/10-storage.md.
  3. If wallpaper rendering, first paint, settings UI, language, search, or command palette storage is touched, read the matching rule file from .claude/rules/README.md.

Version Rules

  • DB_VERSION is only for IndexedDB structure: object stores, indexes, keyPath, or autoIncrement.
  • LS_VERSION / ptab_schema_version is for PlainTab application data semantics.
  • If an IndexedDB-only change affects key names, record shape, references, old data cleanup, or jump upgrades, bump LS_VERSION and add a WallpaperData.migrate() path.
  • Do not use IndexedDB version upgrades for application-level migration decisions.
  • Pure discardable cache changes do not need LS_VERSION if missing or stale cache cannot be misread and does not require cleanup.

Migration Discipline

Before production edits, write or update a focused check in docs/ai-tasks/ and watch it fail for the missing migration behavior.

For each migration step:

  1. Detect from persisted data, not app release numbers. Prefer ptab_schema_version, legacy ptab_version, old key presence, and current model facts.
  2. Make the step idempotent. A browser close midway must be safe to retry.
  3. Write large data first, then write references.
  4. Never write references to missing Blob records.
  5. Remove references before deleting large data.
  6. Mark migration complete only after required new data and cleanup succeed.
  7. Do not overwrite non-default data already created by a newer version.
  8. Keep runtime modules reading only the current schema after migration.

Cleanup Rules

  • Delete obsolete localStorage keys after successful migration.
  • Delete obsolete IndexedDB keys with targeted deletes. Do not delete the whole PlainTab database while current data uses the same store.
  • Avoid permanent top-level marker keys for one-off migrations. If cleanup truly needs an idempotent retry marker, keep it scoped to an existing owned model, document why persisted facts are insufficient, and include a cleanup/removal path.
  • Keep old migration code for enough releases to support users who skip versions.

Read the full file on GitHub · 57 lines

Files

What ships with it

1 file 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. 4d ago First seen · 57 lines · 63 tokens per session scan A edc28c19d9fb

Subscribe to this mod's changes

storage-migration is a skill published in the GitHub repository kaininx/PlainTab (88 stars, last pushed 3mo ago), licensed MIT. It adds 63 tokens to every session and 663 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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