living-design-documents

living-design-documents is a skill for Claude Code, Codex from KemingHe/common-devx. It costs 55 tokens per session (4,037 once invoked), scanned A, original, MIT.

A documentation method built around three evolving design documents: core decisions, detailed specifications, and deferred questions. It keeps important project choices recorded as the software grows.

In plain words
What is it for?
Use it when starting a project, making significant design decisions, managing growing complexity, or reviewing documents that have not been updated recently.
Why use it?
It gives developers a shared place to capture decisions, describe how the system should work, and postpone unresolved topics without losing them.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: installed under .agents/ (shared by several agents).

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/keminghe/common-devx/living-design-documents
Any agent
npx skills add KemingHe/common-devx --skill living-design-documents
Clone the repo
git clone --depth 1 https://github.com/KemingHe/common-devx

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 living-design-documents

README.md
[![agentmods](https://agentmods.dev/badge/skills/keminghe/common-devx/living-design-documents.svg)](https://agentmods.dev/skills/keminghe/common-devx/living-design-documents)
Your own site
<a href="https://agentmods.dev/skills/keminghe/common-devx/living-design-documents"><img src="https://agentmods.dev/badge/skills/keminghe/common-devx/living-design-documents.svg" alt="Measured on agentmods" height="20"></a>
Per session 55 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 4,037 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 5.1 $0.00055 $0.04037
Opus 5 $0.00028 $0.02018
Sonnet 5 $0.00011 $0.00807
Haiku 4.5 $0.00006 $0.00404

Measured 6d ago against content hash 7fab18b377f7, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

living-design-documents 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 6d 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/living-design-documents/SKILL.md · 328 lines

How it starts

The opening of the file, as written. The whole thing — 328 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Living Design Documents

Create and maintain three living design documents that guide development through structured design thinking. Core Decisions capture load-bearing policies. Taxonomy provides detailed specifications. Parked holds deferred analysis. Documents graduate upward as maturity increases.

Temporary persona: Senior engineering PM with expertise in structured design and AI-native documentation.

When to Use This Skill

  • New project setup requiring initial design structure
  • Design decisions needed during development
  • Complexity growing and requiring documentation
  • Audit due (7 days for solo projects, 30 days for team projects since Last Audited date)
  • User triggers: "design docs", "LDD", "core decisions", "taxonomy", "parked decisions"

Asset Resolution

  1. Check ./assets/design-*-template.md (skill-local)
  2. If not found, search **/design-*-template.md in repository
  3. If still not found, generate from scratch following the template structure in this skill

Simple vs Complex Project Adaptation

Templates default to simple project pattern. Adapt based on project complexity:

Project Type Core Decisions Taxonomy Parked
Simple (single-focus) design-core-decisions.md design-taxonomy.md design-parked.md
Complex (multi-component) design-core-decisions.md design-taxonomy-[component].md design-parked-[component].md

Detection heuristics:

  • Simple: <5 major components, single team, focused purpose
  • Complex: 5+ components, multiple teams, or distinct bounded contexts

Template adaptation examples for complex projects:

Element Simple (template default) Complex (agent adapts)
Taxonomy filename design-taxonomy.md design-taxonomy-api.md
Taxonomy title # Design - Taxonomy # Design - Taxonomy - API
Parked filename design-parked.md design-parked-api.md
Parked title # Design - Parked # Design - Parked - API
Taxonomy NOTE links ./design-parked.md ./design-parked-api.md, ./design-taxonomy-database.md
Parked NOTE links ./design-taxonomy.md ./design-taxonomy-api.md
References section Omit cross-component links Add cross-component section anchors

Read the full file on GitHub · 328 lines

Files

What ships with it

4 files 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. 6d ago First seen · 328 lines · 55 tokens per session scan A 7fab18b377f7

Subscribe to this mod's changes

living-design-documents is a skill published in the GitHub repository KemingHe/common-devx (10 stars, last pushed 3mo ago), licensed MIT. It adds 55 tokens to every session and 4,037 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 2026-08-31.