sdd-shape

sdd-shape is a command for coding agents from maquina-app/rails-claude-code. It costs 16 tokens per session (437 once invoked), scanned A, original, MIT.

A command for shaping a feature specification in a Rails project, using questions, code searches, standards, and a spec.md file. Spec-driven development means defining the work before implementing it.

In plain words
What is it for?
Creating a dated feature folder, recording codebase findings, checking for UI designs, and drafting the feature specification.
Why use it?
It turns an incomplete feature idea into a documented plan based on the existing code and project standards.

Command

Part of the spec-driven-development plugin — 1 skill, 6 commands shipped together

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 commands/maquina-app/rails-claude-code/sdd-shape
Clone the repo
git clone --depth 1 https://github.com/maquina-app/rails-claude-code

Or install spec-driven-development, the plugin that ships this one along with the rest of its 1 skill, 6 commands.

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 sdd-shape

README.md
[![agentmods](https://agentmods.dev/badge/commands/maquina-app/rails-claude-code/sdd-shape.svg)](https://agentmods.dev/commands/maquina-app/rails-claude-code/sdd-shape)
Your own site
<a href="https://agentmods.dev/commands/maquina-app/rails-claude-code/sdd-shape"><img src="https://agentmods.dev/badge/commands/maquina-app/rails-claude-code/sdd-shape.svg" alt="Measured on agentmods" height="20"></a>
Per session 16 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 437 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 $0.00016 $0.00437
Opus 5 $0.00008 $0.00218
Sonnet 5 $0.00003 $0.00087
Haiku 4.5 $0.00002 $0.00044

Measured 5d ago against content hash 57b30629fe0d, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

sdd-shape 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 5d 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.

spec-driven-development/commands/sdd-shape.md · 43 lines

What it actually says

Shape a feature spec for this Rails project using the spec-driven-development skill.

Process

1. Create the spec folder

Create sdd/specs/YYYY-MM-DD-[feature-name]/ using today's date and a descriptive kebab-case name.

2. Ask focused discovery questions (4–6 max)

  • What is the user trying to accomplish? What is the happy path?
  • Are there edge cases that need handling in v1?
  • What does success look like? (redirect destination, flash message, UI change)
  • Are there existing models, controllers, or views to reuse or extend?

3. Search the codebase for existing patterns

Before writing anything, search for related code:

grep -r "class.*ApplicationRecord" app/models/
ls app/controllers/
find app/views -name "*.html.erb" | head -30

Write findings to sdd/specs/[folder]/references.md.

4. Check for visuals

Ask if mockups or wireframes exist. If none and the feature has meaningful UI, use the frontend-design skill to create an HTML mockup.

5. Inject relevant standards

Read sdd/standards/index.yml. Based on what the feature touches, present the applicable standards to the user for confirmation. Then write the full file content of each confirmed standard into sdd/specs/[folder]/standards.md.

6. Write spec.md

Create sdd/specs/[folder]/spec.md with:

  • Goal — one sentence
  • User Stories — As a [user], I want [action] so that [outcome]
  • Requirements — functional only, no implementation details
  • Visual Design — mockup link or layout description
  • Out of Scope — explicitly what is NOT in v1

Update sdd/progress.yml when complete. Suggest running /sdd-tasks next.

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. 5d ago First seen · 43 lines · 16 tokens per session scan A 57b30629fe0d

Subscribe to this mod's changes

sdd-shape is a command published in the GitHub repository maquina-app/rails-claude-code (47 stars, last pushed 19d ago), licensed MIT. It adds 16 tokens to every session and 437 once invoked, about $0.0001 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.