openspec-plus-design

openspec-plus-design is a skill for Claude Code, Codex from sudokar/openspec-plus. It costs 82 tokens per session (4,180 once invoked), scanned A, original, MIT.

A required design workflow for OpenSpec, a system for writing and managing software-change proposals. It guides brainstorming, comparison of alternatives, user choices, and review before a design document is written.

In plain words
What is it for?
Use it when creating, continuing, exploring, reviewing, or refining an OpenSpec design.
Why use it?
It reduces the risk of choosing an architecture too early or writing a complete design before its assumptions and trade-offs have been discussed.

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/sudokar/openspec-plus/openspec-plus-design
Any agent
npx skills add sudokar/openspec-plus --skill openspec-plus-design
Clone the repo
git clone --depth 1 https://github.com/sudokar/openspec-plus

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 openspec-plus-design

README.md
[![agentmods](https://agentmods.dev/badge/skills/sudokar/openspec-plus/openspec-plus-design.svg)](https://agentmods.dev/skills/sudokar/openspec-plus/openspec-plus-design)
Your own site
<a href="https://agentmods.dev/skills/sudokar/openspec-plus/openspec-plus-design"><img src="https://agentmods.dev/badge/skills/sudokar/openspec-plus/openspec-plus-design.svg" alt="Measured on agentmods" height="20"></a>
Per session 82 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,180 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 $0.00082 $0.04180
Opus 5 $0.00041 $0.02090
Sonnet 5 $0.00016 $0.00836
Haiku 4.5 $0.00008 $0.00418

Measured 3d ago against content hash 156da2fbf015, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

openspec-plus-design 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 3d 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/openspec-plus-design/SKILL.md · 366 lines

How it starts

The opening of the file, as written. The whole thing — 366 lines — stays where its author put it; the contents beside it link to each section on GitHub.

OpenSpec Plus Design

Mission

Strengthen OpenSpec design with brainstorming patterns. Prevent premature architectural convergence — explore alternatives, compare tradeoffs, recommend, get user selection, build incrementally, validate vs proposal (and any existing spec) before writing design.md.


This skill is RIGID. Do NOT write any design file before all workflow phases complete through Phase 3 section approvals. After writing, reviewer subagent is MANDATORY — skipping review is a skill violation.

Red flags — STOP, you are about to violate this skill:

  • "There's only one obvious approach"
  • "I'll generate the full design and let the user review at the end"
  • "The user is in a hurry, I'll skip selection"
  • "I'll group all sections into one approval question"
  • "I have approval for the direction, so I can write the whole document now"
  • "The proposal (and spec, if it exists) is fresh, I don't need the reviewer subagent"
  • "Spec doesn't exist yet, I can sneak some requirements into the design"
  • "The design looks fine to me, I'll skip the reviewer subagent"
  • "Reviewer flagged minor issues, I'll re-dispatch after fixing to confirm"

Inputs Available

OpenSpec allows either order after proposal:

  • proposal → spec → design (spec exists)
  • proposal → design → spec (no spec yet)

When this skill runs:

  • ALWAYS read approved proposal — authoritative for intent and capabilities
  • If spec exists, ALWAYS read it — design MUST align with it
  • If no spec yet, design works from proposal capabilities only — do NOT capture detailed requirements (that's spec phase, runs after design)
  • Design MUST align with proposal AND any existing spec

Workflow

Five phases. NEVER skip, merge, or reorder.

Phase 0: Schema & Template Resolution
Phase 1: Explore Design Approaches
Phase 2: Select Design Direction
Phase 3: Build Design Sections
Phase 4: Generate Design

Workflow Visibility (MANDATORY)

Display workflow phases via task tool at start; update as each phase completes.

Read the full file on GitHub · 366 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. 3d ago First seen · 366 lines · 82 tokens per session scan A 156da2fbf015

Subscribe to this mod's changes

openspec-plus-design is a skill published in the GitHub repository sudokar/openspec-plus (154 stars, last pushed 4d ago), licensed MIT. It adds 82 tokens to every session and 4,180 once invoked, about $0.0004 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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