Name: Generate mspec Delta Spec
Author: Skills Guide Bot

Automated summary

Generates the Delta Specs for an mspec change: it initialises one spec.md per touched capability, auto-numbers FR-NNN requirements, and writes each requirement in EARS format with at least one GIVEN/WHEN/THEN scenario.

Strengths

Automatic FR-NNN numbering by reading existing specs, which prevents identifier collisions across changes.
Enforces EARS patterns and RFC 2119 keywords (SHALL/MUST/SHOULD/MAY) with sentence templates selected from the project's ja or en locale.
Built-in verification chain: mspec validate, anchor check and spec lint, with rollback of the readme checkbox when validation fails.
Keeps the artifact checklist in readme.md in sync and hands control back to the workflow through /mspec:continue.

Limitations

Fully dependent on the mspec CLI and on an existing change whose proposal.md lists the touched capabilities.
Provides no domain content: the user still has to write the requirement bodies and scenarios themselves.
Several instructions and messages are written in Japanese, which can be confusing for non-Japanese-speaking users.

When to use it

Use it once an mspec change has an approved proposal and its Delta Specs must be created or updated before implementation.

When not to use it

Do not use it to write a specification outside the mspec workflow, or in a project where the mspec CLI is not installed.

Security analysis

Caution

Quality score86/100

The skill is a structured workflow assistant that runs project-local CLI commands and edits markdown artifacts. It has execution side effects and file-write capability, so it merits caution, but all described actions are legitimate, bounded, and non-destructive.

Findings

•Instructs running external `mspec` CLI commands (`status`, `delta init`, `validate`, `anchor check`, `spec lint`) which execute local tooling and may modify repository files.
•Instructs editing generated spec files and updating `readme.md` checkboxes; scope is limited to the change directory and workflow artifacts.
•No destructive commands, credential access, network exfiltration, obfuscated payloads, or safety-disabling instructions found.

How this analysis is made

Examples

Start the delta step

/mspec:delta --change 2026-05-20-101500-add-csv-export

Fix after a failed validation

mspec validate --change 2026-05-20-101500-add-csv-export fails with duplicate FR-IDs; re-run /mspec:delta so the numbering and the H4 scenarios get corrected.

English-locale project

The project locale is en — run /mspec:delta and write the requirements as "When <trigger>, the system SHALL <response>." with GIVEN/WHEN/THEN scenarios.

name: mspec-delta description: delta step of mspec workflow — generate Delta Spec with auto-numbered FR-NNN when_to_use: User runs /mspec:delta, or workflow auto-continues to delta

Procedure

Run mspec status --change <change-dir> --json first.
Read proposal.md → extract capability names from ## Capabilities (touched).
For each capability, run mspec delta init --capability <name> --change <change-dir>. The CLI auto-numbers FR-NNN by reading existing specs/<name>/spec.md.
Edit each generated changes/<change-dir>/specs/<capability>/spec.md:
- Replace placeholders in ### Requirement: FR-NNN — <Short Title> headers (H3).
- Write the Requirement body in EARS format using RFC 2119 keywords with the following semantics (per Constitution):
  - SHALL — 機能要件（system の振る舞いを規定するデフォルト）
  - MUST — 制約・安全要件（絶対的強制または禁止）
  - SHOULD — 推奨（逸脱可能だが理由が必要）
  - MAY — 任意（オプション機能）
- EARS pattern guidance — read "locale" from the mspec status --json output (step 1) and use the matching format:
  - locale=ja の場合:
    - Ubiquitous: このシステムは SHALL <振る舞い>.
    - Event-Driven: <トリガー> のとき、このシステムは SHALL <振る舞い>.
    - State-Driven: <状態> の間、このシステムは SHALL <振る舞い>.
    - Unwanted Behavior: <条件> の場合、このシステムは SHALL <振る舞い>.
    - Optional Feature: <機能> が有効な場合、このシステムは SHALL <振る舞い>.
  - locale=en の場合（locale フィールドが undefined の場合も含む）:
    - Ubiquitous: The system SHALL <response>.
    - Event-Driven: When <trigger>, the system SHALL <response>.
    - State-Driven: While <state>, the system SHALL <response>.
    - Unwanted Behavior: If <condition>, then the system SHALL <response>.
    - Optional Feature: Where <feature>, the system SHALL <response>.
- Add at least one #### Scenario: <Name> (must be H4) with - GIVEN, - WHEN, - THEN bullets nested inside each Requirement.
readme.md の ## Artifacts 節の - [ ] specs/*/spec.md (Delta Spec) を - [x] specs/*/spec.md (Delta Spec) に更新する。
Run mspec validate --change <change-dir> (validates FR-ID uniqueness and H4 Scenarios). validate が失敗した場合は - [x] specs/*/spec.md (Delta Spec) を - [ ] specs/*/spec.md (Delta Spec) にロールバックする。
block: false — auto-continue via /mspec:continue.

Verification (C2)

mspec validate --change <change> — アーティファクト整合性チェック
mspec anchor check --change <change> — アンカー解決確認
mspec spec lint — Delta Spec実装詳細漏洩チェック

Learning (C3)

このスキルの実行で発生した学習候補を記録する:

<!-- LEARNING: <パターン説明> | source: <FR-ID> | confidence: low|medium|high -->

mspec learn コマンドが archive 済み changes からこれらを収集してpost-condition候補をproposeする。

From the file to a first result

The download contains exactly the content displayed on this page. This copy may differ from the latest version in the source repository.

View the source and supporting files

This download contains SKILL.md only. Any scripts, references, templates and dependencies are not included. Get the required files from the source, preserving their directory structure, before continuing.

1. Download the file

Download SKILL.md

From the root of a test project, save the file as .skill-downloads/generate-mspec-delta-spec-mrwakdml/SKILL.md, or use the command below. This folder is for inspecting the skill before installation.

Command for macOS/Linux or WSL: requires a POSIX shell and curl. On Windows without WSL, use the download button and create the folder manually.

mkdir -p '.skill-downloads/generate-mspec-delta-spec-mrwakdml' && curl --fail --show-error --location 'https://skills-guides.com/api/skills/generate-mspec-delta-spec-mrwakdml/download' --output '.skill-downloads/generate-mspec-delta-spec-mrwakdml/SKILL.md.part' && mv '.skill-downloads/generate-mspec-delta-spec-mrwakdml/SKILL.md.part' '.skill-downloads/generate-mspec-delta-spec-mrwakdml/SKILL.md'

2. Check prerequisites

Read SKILL.md before using it. If it references scripts or external services, inspect them and prepare the required access in your test environment.

No recognized prerequisites section in this file. This does not mean it is self-contained: libraries, tools and access requirements may be mentioned elsewhere in the content or source repository.

The platforms on this page are catalog indications. The paths below follow tool documentation; they do not prove this skill has been run in those tools. No minimum tool version is confirmed for this listing.

3. Load the skill

After inspection, copy the complete folder into your project using one of the commands below, then open a new tool session. The command stops if a folder with the same name already exists: compare the files before replacing it.

Claude Code

test -f '.skill-downloads/generate-mspec-delta-spec-mrwakdml/SKILL.md' && test -s '.skill-downloads/generate-mspec-delta-spec-mrwakdml/SKILL.md' && mkdir -p '.claude/skills' && test ! -e '.claude/skills/mspec-delta' && cp -R '.skill-downloads/generate-mspec-delta-spec-mrwakdml' '.claude/skills/mspec-delta'

OpenSkills

OpenSkills must already be installed. The local install/read procedure is checked with OpenSkills 1.5.0, which requires Node.js ≥ 20.6.0. Catalog slugs are not resolved automatically.

Official OpenSkills installation

openskills install './.skill-downloads/generate-mspec-delta-spec-mrwakdml'

openskills read 'generate-mspec-delta-spec-mrwakdml'

Reading should display the installed file content and its base directory. It does not run the skill or install its dependencies.

For an agent that reads AGENTS.md, then sync the index. This command changes AGENTS.md: review the diff before using it.

openskills sync

Manual method or another tool: attach SKILL.md to a conversation, or open it in an agent that can read files. Include any required supporting resources. No universal folder is recognized by every tool.

4. Try a first task

Use a short, synthetic input: an API endpoint, a small document or an interface brief. In a new conversation, attach the file or give the agent its path, then adapt this request:

Read .skill-downloads/generate-mspec-delta-spec-mrwakdml/SKILL.md and apply its instructions to this example: [describe a test input]. Identify any missing files, dependencies or access. Produce the result requested by the skill without inventing data or running unreviewed scripts.

Expected result: output matching the skill instructions, or a precise list of missing prerequisites. A read confirmation alone does not validate a first use. If an external resource is unavailable, that path remains untested.

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Skills Guide Bot