sdd-spec
Write specifications with requirements and scenarios (delta specs for changes). Trigger: When the orchestrator launches you to write or update specs for a change.
Packaged view
This page reorganizes the original catalog entry around fit, installability, and workflow context first. The original raw source lives below.
Install command
npx @skill-hub/cli install gentleman-programming-gentleman-dots-sdd-spec
Repository
Skill path: GentlemanClaude/skills/sdd-spec
Write specifications with requirements and scenarios (delta specs for changes). Trigger: When the orchestrator launches you to write or update specs for a change.
Open repositoryBest for
Primary workflow: Ship Full Stack.
Technical facets: Full Stack.
Target audience: everyone.
License: MIT.
Original source
Catalog source: SkillHub Club.
Repository owner: Gentleman-Programming.
This is still a mirrored public skill entry. Review the repository before installing into production workflows.
What it helps with
- Install sdd-spec into Claude Code, Codex CLI, Gemini CLI, or OpenCode workflows
- Review https://github.com/Gentleman-Programming/Gentleman.Dots before adding sdd-spec to shared team environments
- Use sdd-spec for development workflows
Works across
Favorites: 0.
Sub-skills: 0.
Aggregator: No.
Original source / Raw SKILL.md
---
name: sdd-spec
description: >
Write specifications with requirements and scenarios (delta specs for changes).
Trigger: When the orchestrator launches you to write or update specs for a change.
license: MIT
metadata:
author: gentleman-programming
version: "2.0"
---
## 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, or REMOVED from the system's behavior.
## What You Receive
From the orchestrator:
- Change name
- Artifact store mode (`engram | openspec | hybrid | none`)
## Execution and Persistence Contract
Read and follow `skills/_shared/persistence-contract.md` for mode resolution rules.
- If mode is `engram`:
**CRITICAL: `mem_search` returns 300-char PREVIEWS, not full content. You MUST call `mem_get_observation(id)` for EVERY artifact. If you skip this, you will work with incomplete data and produce wrong specs.**
**STEP A — SEARCH** (get IDs only — content is truncated):
1. `mem_search(query: "sdd/{change-name}/proposal", project: "{project}")` → save ID
**STEP B — RETRIEVE FULL CONTENT** (mandatory):
2. `mem_get_observation(id: {proposal_id})` → full proposal content (REQUIRED)
**DO NOT use search previews as source material.**
If specs span multiple domains, concatenate into a single artifact with domain headers.
**Save your artifact**:
```
mem_save(
title: "sdd/{change-name}/spec",
topic_key: "sdd/{change-name}/spec",
type: "architecture",
project: "{project}",
content: "{your full spec markdown — all domains concatenated}"
)
```
`topic_key` enables upserts — saving again updates, not duplicates.
(See `skills/_shared/engram-convention.md` for full naming conventions.)
- If mode is `openspec`: Read and follow `skills/_shared/openspec-convention.md`.
- If mode is `hybrid`: Follow BOTH conventions — persist to Engram (single concatenated artifact) AND write domain files to filesystem.
- If mode is `none`: Return result only. Never create or modify project files.
## What to Do
### Step 1: Load Skill Registry
**Do this FIRST, before any other work.**
1. Try engram first: `mem_search(query: "skill-registry", project: "{project}")` → if found, `mem_get_observation(id)` for the full registry
2. If engram not available or not found: read `.atl/skill-registry.md` from the project root
3. If neither exists: proceed without skills (not an error)
From the registry, identify and read any skills whose triggers match your task. Also read any project convention files listed in the registry.
### Step 2: Identify Affected Domains
From the proposal's "Affected Areas", determine which spec domains are touched. Group changes by domain (e.g., `auth/`, `payments/`, `ui/`).
### Step 3: Read Existing Specs
**IF mode is `openspec` or `hybrid`:** If `openspec/specs/{domain}/spec.md` exists, read it to understand CURRENT behavior. Your delta specs describe CHANGES to this behavior.
**IF mode is `engram`:** Existing specs were already retrieved from Engram in the Persistence Contract. Skip filesystem reads.
**IF mode is `none`:** Skip — no existing specs to read.
### Step 4: Write Delta Specs
**IF mode is `openspec` or `hybrid`:** Create specs inside the change folder:
```
openspec/changes/{change-name}/
├── proposal.md ← (already exists)
└── specs/
└── {domain}/
└── spec.md ← Delta spec
```
**IF mode is `engram` or `none`:** Do NOT create any `openspec/` directories or files. Compose the spec content in memory — you will persist it in Step 5.
#### Delta Spec Format
```markdown
# Delta for {Domain}
## ADDED Requirements
### Requirement: {Requirement Name}
{Description using RFC 2119 keywords: MUST, SHALL, SHOULD, MAY}
The system {MUST/SHALL/SHOULD} {do something specific}.
#### Scenario: {Happy path scenario}
- GIVEN {precondition}
- WHEN {action}
- THEN {expected outcome}
- AND {additional outcome, if any}
#### Scenario: {Edge case scenario}
- GIVEN {precondition}
- WHEN {action}
- THEN {expected outcome}
## MODIFIED Requirements
### Requirement: {Existing Requirement Name}
{New description — replaces the existing one}
(Previously: {what it was before})
#### Scenario: {Updated scenario}
- GIVEN {updated precondition}
- WHEN {updated action}
- THEN {updated outcome}
## REMOVED Requirements
### Requirement: {Requirement Being Removed}
(Reason: {why this requirement is being deprecated/removed})
```
#### For NEW Specs (No Existing Spec)
If this is a completely new domain, create a FULL spec (not a delta):
```markdown
# {Domain} Specification
## Purpose
{High-level description of this spec's domain.}
## Requirements
### Requirement: {Name}
The system {MUST/SHALL/SHOULD} {behavior}.
#### Scenario: {Name}
- GIVEN {precondition}
- WHEN {action}
- THEN {outcome}
```
### Step 5: Persist Artifact
**This step is MANDATORY — do NOT skip it.**
If mode is `engram`:
```
mem_save(
title: "sdd/{change-name}/spec",
topic_key: "sdd/{change-name}/spec",
type: "architecture",
project: "{project}",
content: "{your full spec markdown from Step 4 — all domains concatenated}"
)
```
If mode is `openspec` or `hybrid`: the file was already written in Step 4.
If mode is `hybrid`: also call `mem_save` as above (write to BOTH backends).
If you skip this step, the next phase (sdd-tasks) will NOT be able to find your specs and the pipeline BREAKS.
### Step 6: Return Summary
Return to the orchestrator:
```markdown
## Specs Created
**Change**: {change-name}
### Specs Written
| Domain | Type | Requirements | Scenarios |
|--------|------|-------------|-----------|
| {domain} | Delta/New | {N added, M modified, K removed} | {total scenarios} |
### Coverage
- Happy paths: {covered/missing}
- Edge cases: {covered/missing}
- Error states: {covered/missing}
### Next Step
Ready for design (sdd-design). If design already exists, ready for tasks (sdd-tasks).
```
## Rules
- ALWAYS use Given/When/Then format for scenarios
- ALWAYS use RFC 2119 keywords (MUST, SHALL, SHOULD, MAY) for requirement strength
- If existing specs exist, write DELTA specs (ADDED/MODIFIED/REMOVED sections)
- If NO existing specs exist for the domain, write a FULL spec
- Every requirement MUST have at least ONE scenario
- Include both happy path AND edge case scenarios
- Keep scenarios TESTABLE — someone should be able to write an automated test from each one
- DO NOT include implementation details in specs — specs describe WHAT, not HOW
- Apply any `rules.specs` from `openspec/config.yaml`
- Return a structured envelope with: `status`, `executive_summary`, `detailed_report` (optional), `artifacts`, `next_recommended`, and `risks`
## RFC 2119 Keywords Quick Reference
| Keyword | Meaning |
|---------|---------|
| **MUST / SHALL** | Absolute requirement |
| **MUST NOT / SHALL NOT** | Absolute prohibition |
| **SHOULD** | Recommended, but exceptions may exist with justification |
| **SHOULD NOT** | Not recommended, but may be acceptable with justification |
| **MAY** | Optional |