shape-up

A collaborative method for turning a vague software idea into a design specification. It starts with the overall vision and gradually works down to scope, building blocks, and details.

In plain words
What is it for?
Use it to plan a system, shape a project, or write a design spec. Unknown decisions can be marked for later instead of stopping the planning process.
Why use it?
It keeps large or unclear projects understandable by resolving the big decisions before focusing on implementation details.

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/thaitype/chief/shape-up
Any agent
npx skills add thaitype/chief --skill shape-up
Clone the repo
git clone --depth 1 https://github.com/thaitype/chief

Made for: Claude Code, Codex.

Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,010 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 $0.00080 $0.01010
Opus 5 $0.00040 $0.00505
Sonnet 5 $0.00016 $0.00202
Haiku 4.5 $0.00008 $0.00101

Measured 3d ago against content hash a079332da889, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

shape-up 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/engineering/shape-up/SKILL.md · 92 lines

How it starts

The opening of the file, as written. The whole thing — 92 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Shape Up — Top-Down Design Spec

Shape a vague idea into a clear design spec by working top-down: start from the big picture, confirm alignment at each layer, then go deeper. This is NOT an interview — it's collaborative writing where the agent drafts and the user shapes.

When to Use

  • User says "shape up", "design spec", "let's design", "plan a system", "I need to think through this"
  • User has a large or ambiguous project and needs to see the big picture first
  • Before /grill-design — when the scope isn't clear enough to grill on details yet

Core Principle

One layer at a time. Confirm before going deeper. Never jump ahead.

If the user can't answer something at the current layer, mark it [TBD] and move on. Don't drill down into unknowns — that's how people lose focus.

Workflow

Layer 1: Vision

Ask the user to describe what they're building in plain language. Then co-write a short vision block:

  • What — one sentence describing the thing
  • Why — what problem it solves, who it's for
  • Done looks like — how you'd know it succeeded

Draft this as a short block (5-8 lines max). Show it to the user. Adjust until they say it's right.

Do NOT ask about tech stack, architecture, or implementation yet.

Layer 2: Scope

Now that the vision is clear, co-write the scope:

  • In scope — what this project will do (bullet list)
  • Out of scope — what it explicitly won't do (bullet list)
  • Constraints — timeline, tech, team, budget, dependencies
  • Users / Actors — who interacts with it

Draft and show. The user cuts, adds, moves things between in/out scope. Keep going until scope feels tight.

If scope is getting too big, say so: "This feels like it's growing — want to split it?"

Layer 3: Building Blocks

Break the in-scope work into 3-7 big blocks. Each block is a major component, feature area, or workstream. For each block:

  • Name — short label
  • Purpose — one line
  • Depends on — which other blocks it needs

Read the full file on GitHub · 92 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 · 92 lines · 80 tokens per session scan A a079332da889

Subscribe to this mod's changes

shape-up is a skill published in the GitHub repository thaitype/chief (56 stars, last pushed 1mo ago), licensed MIT. It adds 80 tokens to every session and 1,010 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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