design-doc

design-doc is a skill for Claude Code from d-mariano/spicyclaude. It costs 52 tokens per session (5,353 once invoked), scanned A, original, MIT.

An interactive workflow that turns a product requirements document (PRD) into a technical design document. It reviews the design section by section and creates a companion document describing the exact data exchanged between system parts.

In plain words
What is it for?
Turning requirements, research, and optional technical files into an agreed system design and detailed data contracts.
Why use it?
It exposes unresolved design choices before coding begins, so people can agree on how the system should work instead of relying on hidden assumptions.

Skill for Claude Code

Written for Claude Code: allowed-tools in frontmatter. Also seen: names the AskUserQuestion tool.

Good fit Turning requirements, research, and optional technical files into an agreed system design and detailed data contracts.

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Install with agentmods
npx agentmods add skills/d-mariano/spicyclaude/design-doc
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 d-mariano/spicyclaude --skill design-doc
Clone the repo
git clone --depth 1 https://github.com/d-mariano/spicyclaude

Made for: Claude Code.

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 design-doc

README.md
[![agentmods](https://agentmods.dev/badge/skills/d-mariano/spicyclaude/design-doc/github.svg)](https://agentmods.dev/skills/d-mariano/spicyclaude/design-doc)
Your own site
<a href="https://agentmods.dev/skills/d-mariano/spicyclaude/design-doc"><img src="https://agentmods.dev/badge/skills/d-mariano/spicyclaude/design-doc/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 design-doc

Your own site · 80×15
<a href="https://agentmods.dev/skills/d-mariano/spicyclaude/design-doc"><img src="https://agentmods.dev/badge/skills/d-mariano/spicyclaude/design-doc.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 52 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 5,353 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. 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 $0.00052 $0.05353
Opus 5 $0.00026 $0.02677
Sonnet 5 $0.00010 $0.01071
Haiku 4.5 $0.00005 $0.00535

Measured 10d ago against content hash c9cccb4c583a, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

design-doc 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 10d 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/design-doc/SKILL.md · 283 lines

How it starts

The opening of the file, as written. The whole thing — 283 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Design Document Workflow

Produce a technical design document interactively from a PRD, supporting research, and optional technical artifacts. The output is an alignment artifact: it gets humans (and AI) agreeing on the shape of the system before code is written.

This workflow does not invent requirements. It synthesizes design from the inputs the user supplies, raises every choice that isn't already specified, and never makes silent assumptions on the user's behalf.

Inputs

In priority order:

  1. PRD (required) — problem statement, use cases, constraints, committed requirements. Authoritative: its decisions are baked in and not re-litigated.
  2. Research (recommended) — prior art, technology comparisons, recommendations, alternatives. Informational: recommendations and alternatives feed AskUserQuestion options; user owns the decision.
  3. Technical artifacts (optional) — code-as-design files: abstractions, contracts, type definitions, data models. Treat as decided for whatever they specify; cite them like a PRD section.

Input modes

  • In context — PRD/research/artifacts are already in the conversation. Use what's there; don't re-read.
  • On disk — user supplied paths. Read each one in full.

If you can't tell which mode applies, ask via AskUserQuestion. If no PRD exists in either form, confirm via AskUserQuestion whether to proceed in spike mode (every requirement-shaped value becomes an Open Question with a working assumption instead of a concrete commitment — for exploration, not committed design).

Critical Rules

  1. Don't fabricate. Every value in the design must trace back to an input or to a user decision.
    • No silent assumptions. Every choice the user has not made must be either (a) sourced from PRD/research/artifacts, (b) raised via AskUserQuestion and decided in the relevant section, or (c) recorded as deferred with a working assumption the user explicitly accepts.
    • Options come from given context only. Don't draw on training-data preferences. If a decision needs an option set and the inputs don't suggest any, that's an unknown — flag it, don't invent options.
    • Defer requires a working assumption. A defer with no assumption is invalid; mark such questions blocking instead.
  2. Push back when something is unclear, contradictory, or risky. If a user choice conflicts with an earlier section, contradicts the PRD, or seems insane given the inputs, surface the conflict before recording.
  3. Stay at alignment altitude. Describe what the system is — components, contracts, data models, relationships. Code bodies, file-by-file responsibilities, build steps, and S/M/L estimates are out of scope.
  4. Name things concretely. Every type, interface, function, and file must have a real name. "SomeService", "DataProcessor", "handleData" are banned.
  5. The design file must stand alone. Anyone reading it cold must understand the system without the conversation.
  6. Save artifacts incrementally, never silently overwrite. Build /context/[nnn]-<slug>/tdd-[nnn].md section-by-section as choices resolve. Workflow Step 0 covers what to do when files already exist.
  7. AskUserQuestion is the only sanctioned channel for design decisions. Plain-text "which would you prefer?" prompts are not allowed for any decision that lands in tdd-[nnn].md or contracts-[nnn].md. Conversational follow-ups (e.g., when the user says "discuss further") and free-form interjections are fine.

Read the full file on GitHub · 283 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. 10d ago First seen · 283 lines · 52 tokens per session scan A c9cccb4c583a

Subscribe to this mod's changes

design-doc is a skill published in the GitHub repository d-mariano/spicyclaude (5 stars, last pushed 1mo ago), licensed MIT. It adds 52 tokens to every session and 5,353 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.

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