sdd-spec

sdd-spec is a skill for Claude Code from Gentleman-Programming/gentle-ai. It costs 25 tokens per session (2,275 once invoked), scanned A, original, MIT.

A writing aid for SDD delta specifications: documents that describe what a software change must do and gives example situations to clarify the requirements.

In plain words
What is it for?
Use it to write requirements and scenarios for a change when an automated workflow starts specification work.
Why use it?
It turns an intended change into a shared, testable description before implementation begins.

Skill for Claude Code

Written for Claude Code: disable-model-invocation in frontmatter. Also seen: mentions subagents.

Good fit Use it to write requirements and scenarios for a change when an automated workflow starts specification work.

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Install with agentmods
npx agentmods add skills/gentleman-programming/gentle-ai/sdd-spec
About the project

Gentle-AI configures an existing AI coding agent into an engineering environment with persistent memory, planning workflows, skills, tool servers, model routing, and optional review. Developers and teams use it to make coding agents follow project conventions and retain decisions across sessions. The catalogue entries are its skills, commands, agents, and instruction.

Gentleman-Programming/gentle-ai · 6,328 stars · on GitHub · gentle-ai.gentlemanprogramming.com

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 Gentleman-Programming/gentle-ai --skill sdd-spec
Clone the repo
git clone --depth 1 https://github.com/Gentleman-Programming/gentle-ai

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 sdd-spec

README.md
[![agentmods](https://agentmods.dev/badge/skills/gentleman-programming/gentle-ai/sdd-spec.svg)](https://agentmods.dev/skills/gentleman-programming/gentle-ai/sdd-spec)
Your own site
<a href="https://agentmods.dev/skills/gentleman-programming/gentle-ai/sdd-spec"><img src="https://agentmods.dev/badge/skills/gentleman-programming/gentle-ai/sdd-spec.svg" alt="Measured on agentmods" height="20"></a>
Per session 25 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,275 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. Third-party audits
  • NVIDIA SkillSpector pass 7 Sept 2026
How audits are shown
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 $0.00025 $0.02275
Opus 5 $0.00013 $0.01137
Sonnet 5 $0.00005 $0.00455
Haiku 4.5 $0.00003 $0.00228

Measured 4d ago against content hash cf2980e52414, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-07, from the pricing page.

Security

Grade A, and why

sdd-spec 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 4d 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.

internal/assets/skills/sdd-spec/SKILL.md · 255 lines

How it starts

The opening of the file, as written. The whole thing — 255 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Execution Role

Confirm your role before acting. You are the dedicated sdd-spec sub-agent unless you loaded this skill directly through the skill() tool.

  • If you are the sdd-spec sub-agent, continue with the phase work below. Do not delegate. Do not call the Skill tool.
  • If you loaded this skill through the skill() tool, you are the orchestrator. Stop here and delegate to the dedicated sdd-spec sub-agent using your platform's delegation primitive (for example, task(...) or a sub-agent invocation).

Language Domain Contract

Generated technical artifacts default to English. Do not inherit the user's conversational language or the active persona's regional voice for SDD artifacts unless the user explicitly requests that artifact language or the project convention requires it.

If technical artifacts are explicitly requested in another language, use a neutral/professional register unless the user explicitly requests a different tone or regional variant.

Public/contextual comments follow the target context language by default. Explicit user language or tone overrides win; otherwise use a neutral/professional register unless the target context clearly calls for another tone or regional variant.

Purpose

You are a sub-agent responsible for writing SPECIFICATIONS. You take the proposal and produce delta specs — structured requirements and scenarios that describe what's being ADDED, MODIFIED, REMOVED, or RENAMED from the system's behavior.

What You Receive

From the orchestrator:

  • Change name
  • Artifact store mode (engram | openspec | hybrid | none)

Execution and Persistence Contract

Follow Section B (retrieval) and Section C (persistence) from skills/_shared/sdd-phase-common.md.

  • engram: Read sdd/{change-name}/proposal (required). If specs span multiple domains, concatenate into a single artifact with domain headers. Save as sdd/{change-name}/spec.
  • openspec: Read and follow skills/_shared/openspec-convention.md.
  • hybrid: Follow BOTH conventions — persist to Engram (single concatenated artifact) AND write domain files to filesystem.
  • none: Return result only. Never create or modify project files.

Read the full file on GitHub · 255 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. 4d ago Changed · +2 lines cf2980e52414
  2. 8d ago First seen · 253 lines · 25 tokens per session scan A cdb91ee1876a

Subscribe to this mod's changes

sdd-spec is a skill published in the GitHub repository Gentleman-Programming/gentle-ai (6,328 stars, last pushed yesterday), licensed MIT. It adds 25 tokens to every session and 2,275 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.

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