Borrowing it
Nothing to install: this file belongs to mendix/web-widgets. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/mendix/web-widgets/main/.agents/skills/openspec-onboard/SKILL.mdgit clone --depth 1 https://github.com/mendix/web-widgetsWrote 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.
[](https://agentmods.dev/skills/mendix/web-widgets/openspec-onboard)<a href="https://agentmods.dev/skills/mendix/web-widgets/openspec-onboard"><img src="https://agentmods.dev/badge/skills/mendix/web-widgets/openspec-onboard/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.
<a href="https://agentmods.dev/skills/mendix/web-widgets/openspec-onboard"><img src="https://agentmods.dev/badge/skills/mendix/web-widgets/openspec-onboard.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.00026 | $0.03349 |
| Opus 5.5 | $0.00010 | $0.01340 |
| Sonnet 5.5 | $0.00005 | $0.00670 |
| Haiku 4.5 | $0.00003 | $0.00335 |
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 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.
This is a copy
73% identical to openspec-onboard — 180 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.
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:
- TODO/FIXME comments - Search for
TODO,FIXME,HACK,XXXin code files - Missing error handling -
catchblocks that swallow errors, risky operations without try-catch - Functions without tests - Cross-reference
src/with test directories - Type issues -
anytypes in TypeScript files (: any,as any) - Debug artifacts -
console.log,console.debug,debuggerstatements in non-debug code - 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" }
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.
- 1mo ago First seen · 575 lines · 26 tokens per session scan A 14774213b08f
openspec-onboard is a skill published in the GitHub repository mendix/web-widgets (40 stars, last pushed today), licensed Apache-2.0. It adds 26 tokens to every session and 3,349 once invoked, about $0.0001 per session on Opus 5.5. A static security scan graded it A with 0 findings. It is 73% identical to openspec-onboard, differing in 180 lines, and is treated as a copy.
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