offline-first-development

offline-first-development is a skill for Claude Code, Codex from Omar-Obando/qwen-orchestrator. It costs 51 tokens per session (2,245 once invoked), scanned A, original, MIT.

A guide to building applications that continue working without an internet connection and synchronize their data when the connection returns.

In plain words
What is it for?
Use it to design local storage, offline screens, service workers, queued actions, background synchronization, conflict resolution, and offline tests.
Why use it?
It helps handle network failures, offline changes, conflicting updates, and the limits of local storage without losing a usable interface.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to design local storage, offline screens, service workers, queued actions, background synchronization, conflict resolution, and offline tests.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/omar-obando/qwen-orchestrator/offline-first-development
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 Omar-Obando/qwen-orchestrator --skill offline-first-development
Clone the repo
git clone --depth 1 https://github.com/Omar-Obando/qwen-orchestrator

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 offline-first-development

README.md
[![agentmods](https://agentmods.dev/badge/skills/omar-obando/qwen-orchestrator/offline-first-development/github.svg)](https://agentmods.dev/skills/omar-obando/qwen-orchestrator/offline-first-development)
Your own site
<a href="https://agentmods.dev/skills/omar-obando/qwen-orchestrator/offline-first-development"><img src="https://agentmods.dev/badge/skills/omar-obando/qwen-orchestrator/offline-first-development/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 offline-first-development

Your own site · 80×15
<a href="https://agentmods.dev/skills/omar-obando/qwen-orchestrator/offline-first-development"><img src="https://agentmods.dev/badge/skills/omar-obando/qwen-orchestrator/offline-first-development.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 51 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,245 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. 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 $0.00051 $0.02245
Opus 5 $0.00026 $0.01123
Sonnet 5 $0.00010 $0.00449
Haiku 4.5 $0.00005 $0.00225

Measured 8d ago against content hash b4f70aabcbdb, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-12, from the pricing page.

Security

Grade A, and why

offline-first-development scanned grade A with 1 finding 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.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

return fetch(event.request).then((response) => {
skills/offline-first-development/SKILL.md · 352 lines

How it starts

The opening of the file, as written. The whole thing — 352 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Offline-First Development Skill — Mobile Engineer

Overview

This skill provides comprehensive guidance for implementing offline-first applications. It covers local storage management, data synchronization, conflict resolution, offline UI patterns, and offline state management following offline-first development best practices.

When to Use

Use this skill when:

  • Implementing offline-first applications
  • Managing local storage (IndexedDB, localStorage)
  • Implementing data synchronization
  • Handling synchronization conflicts
  • Creating offline UI patterns
  • Implementing service workers
  • Managing offline state
  • Creating offline data models
  • Implementing offline-first APIs
  • Handling network failures
  • Creating offline indicators
  • Implementing queue for offline actions
  • Managing offline data validation
  • Creating offline sync strategies
  • Implementing conflict resolution
  • Managing offline data consistency
  • Creating offline-first UX patterns
  • Implementing background sync
  • Managing offline data caching
  • Creating offline-first error handling
  • Implementing offline data encryption
  • Managing offline storage limits
  • Creating offline-first testing

Do NOT use this skill when:

  • Writing application business logic (use domain-driven skill)
  • Designing database schemas (use database-design skill)
  • Writing API endpoint specifications (use api-design skill)
  • Performing security audits (use security-auditor skill)
  • Writing SQL queries (use sql-best-practices skill)
  • Designing multi-page website layouts (use design-system skill)
  • Analyzing deployment configurations (use deployment skill)
  • Writing documentation (use documentation-best-practices skill)

Offline-First Principles

Core Principles

┌─────────────────────────────────────────────────────────────┐
│              Offline-First Principles                       │
├─────────────────────────────────────────────────────────────┤
│  1. Always Available:                                       │
│     - Application works offline                             │
│     - Core functionality available                          │
│     - Graceful degradation                                  │
│                                                              │
│  2. Data Persistence:                                       │
│     - Data stored locally                                   │
│     - Data survives app restart                             │
│     - Data survives device restart                          │
│                                                              │
│  3. Automatic Sync:                                         │
│     - Data syncs when online                                │
│     - Sync happens automatically                            │
│     - Sync is transparent to user                           │
│                                                              │
│  4. Conflict Resolution:                                    │
│     - Handle offline changes                                │
│     - Resolve conflicts gracefully                          │
│     - User awareness of conflicts                           │
│                                                              │
│  5. Offline UI:                                             │
│     - Clear offline status                                  │
│     - Offline actions queue                                 │
│     - Offline indicators                                    │
└─────────────────────────────────────────────────────────────┘

Read the full file on GitHub · 352 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. 8d ago First seen · 352 lines · 51 tokens per session scan A b4f70aabcbdb

Subscribe to this mod's changes

offline-first-development is a skill published in the GitHub repository Omar-Obando/qwen-orchestrator (49 stars, last pushed 2mo ago), licensed MIT. It adds 51 tokens to every session and 2,245 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 1 finding (makes network calls). No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.