openspec-onboard

Guided onboarding for OpenSpec - walk through a complete workflow cycle with narration and real codebase work.

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/mendix/web-widgets/openspec-onboard
Any agent
npx skills add mendix/web-widgets --skill openspec-onboard
Clone the repo
git clone --depth 1 https://github.com/mendix/web-widgets

Made for: Claude Code, Codex.

Per session 26 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,349 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 73% copy Near-identical to another mod 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 $0.00026 $0.03349
Opus 5 $0.00013 $0.01674
Sonnet 5 $0.00005 $0.00670
Haiku 4.5 $0.00003 $0.00335

Measured today against content hash 14774213b08f, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

openspec-onboard 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 today.

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.

Origin

This is a copy

73% identical to openspec-onboard — 132 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

.agents/skills/openspec-onboard/SKILL.md · 575 lines

How it starts

The opening of the file, as written. The whole thing — 575 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Guide the user through their first complete OpenSpec workflow cycle. This is a teaching experience—you'll do real work in their codebase while explaining each step.


Preflight

Before starting, check if the OpenSpec CLI is installed:

# Unix/macOS
openspec --version 2>&1 || echo "CLI_NOT_INSTALLED"
# Windows (PowerShell)
# if (Get-Command openspec -ErrorAction SilentlyContinue) { openspec --version } else { echo "CLI_NOT_INSTALLED" }

If CLI not installed:

OpenSpec CLI is not installed. Install it first, then come back to /opsx-onboard.

Stop here if not installed.


Phase 1: Welcome

Display:

## Welcome to OpenSpec!

I'll walk you through a complete change cycle—from idea to implementation—using a real task in your codebase. Along the way, you'll learn the workflow by doing it.

**What we'll do:**
1. Pick a small, real task in your codebase
2. Explore the problem briefly
3. Create a change (the container for our work)
4. Build the artifacts: proposal → specs → design → tasks
5. Implement the tasks
6. Archive the completed change

**Time:** ~15-20 minutes

Let's start by finding something to work on.

Phase 2: Task Selection

Codebase Analysis

Scan the codebase for small improvement opportunities. Look for:

  1. TODO/FIXME comments - Search for TODO, FIXME, HACK, XXX in code files
  2. Missing error handling - catch blocks that swallow errors, risky operations without try-catch
  3. Functions without tests - Cross-reference src/ with test directories
  4. Type issues - any types in TypeScript files (: any, as any)
  5. Debug artifacts - console.log, console.debug, debugger statements in non-debug code
  6. Missing validation - User input handlers without validation

Also check recent git activity:

# Unix/macOS
git log --oneline -10 2>/dev/null || echo "No git history"
# Windows (PowerShell)
# git log --oneline -10 2>$null; if ($LASTEXITCODE -ne 0) { echo "No git history" }

Read the full file on GitHub · 575 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. today First seen · 575 lines · 26 tokens per session scan A 14774213b08f

Subscribe to this mod's changes

openspec-onboard is a skill published in the GitHub repository mendix/web-widgets (40 stars, last pushed yesterday), licensed Apache-2.0. It adds 26 tokens to every session and 3,349 once invoked, about $0.0001 per session on Opus 5. A static security scan graded it A with 0 findings. It is 73% identical to openspec-onboard, differing in 132 lines, and is treated as a copy.