Propagate Design Change

Propagate Design Change

What Is This?

The Propagate Design Change skill for the Happycapy Skills platform automates the process of identifying and resolving the impact of changes in a Game Design Document (GDD) across related architectural artifacts. When a GDD is revised, previous architectural decisions, documented as Architectural Decision Records (ADRs), may become outdated or invalid due to the new design direction. This skill scans all ADRs and the traceability index, detects which architectural decisions might now be stale, and generates a detailed change impact report. It then guides the user through the process of updating or resolving those affected ADRs, ensuring architectural consistency and design traceability throughout the project lifecycle.

Skill ID: propagate-design-change
Category: design
Allowed tools: Read, Glob, Grep, Write, Bash, Task
Source: GitHub - Claude-Code-Game-Studios

Why Use It?

Maintaining alignment between the GDD and architectural artifacts is critical in game development projects, where requirements evolve frequently. Manual tracking of design changes and their impact on architecture is error-prone, time-consuming, and can lead to technical debt if overlooked. The Propagate Design Change skill automates this process, delivering several key benefits:

• Consistency: Ensures that ADRs accurately reflect the current GDD, preventing architectural drift.
• Traceability: Tracks which architectural decisions depend on specific GDD sections, making it easier to audit and justify decisions.
• Efficiency: Automates tedious manual reviews, allowing teams to focus on actual problem-solving instead of bookkeeping.
• Risk Reduction: Quickly identifies areas where design changes might introduce inconsistencies or require architectural rework.

By automating change propagation, the skill supports rapid iteration while maintaining architectural integrity.

How to Use It

1. Invoke the

Skill

The skill is user-invocable and expects a single argument: the path to the revised GDD. For example:

/propagate-design-change design/gdd/combat-system.md

Required:

• The path to the changed GDD file.

If the argument is missing, the skill will fail with:

Usage: /propagate-design-change design/gdd/[system].md
Provide the path to the GDD that was changed.

If the file does not exist, the skill will report:

[path] not found. Check the path and try again.

2. Read the Changed

GDD

The skill reads the full contents of the provided GDD file using the allowed tools (such as Read).

3. Retrieve the Previous

Version

The skill uses git to fetch the previous committed version of the GDD:

git show HEAD:design/gdd/[filename].md

• If the file is new (i.e., no previous git history), it reports:
  plaintext

  No previous version in git - this appears to be a new GDD, not a revision.
  Nothing to propagate.

• If the previous version exists, the skill performs a conceptual diff between the current and previous versions.

4. Identify Impacted

ADRs

The skill scans all ADRs and the traceability index using tools like Glob and Grep to determine which ADRs reference or depend on sections of the GDD that have changed. It looks for:

• Added, removed, or modified rules, features, or requirements in the GDD.
• ADRs whose rationale, context, or decision statements reference those altered GDD sections.

5. Generate Change Impact

Report

Based on the diff and references, the skill produces a report detailing:

• Which ADRs are potentially stale or inconsistent with the revised GDD.
• The specific sections in both the GDD and ADRs affected by the change.
• Guidance on how to review or update each impacted ADR.

6. Guide the User Through

Resolution

The skill presents actionable steps to the user:

• Review each affected ADR.
• Update the ADRs to align with the new GDD, or document why the decision still holds.
• Optionally, mark outdated ADRs as superseded or deprecated if the design change invalidates them.

When to Use It

Use the Propagate Design Change skill in any of the following scenarios:

• After committing a significant GDD update that may impact architecture.
• When performing architectural reviews to ensure decisions are current.
• Before major development milestones, to confirm design-architecture alignment.
• As part of continuous integration workflows where design and architecture traceability are required.

It is not necessary to use the skill for initial GDD creation, as it operates on revisions. For new GDDs, the skill will recognize there is nothing to propagate.

Important Notes

• Strict Argument Validation: The skill requires the path to the changed GDD file as its only argument. Incorrect usage or missing files will produce immediate errors.
• Git Dependency: The skill relies on git to retrieve the previous GDD version. Uncommitted changes or files outside version control may not be detected.
• Scope: The skill only propagates changes from GDDs to ADRs and the traceability index. It does not update code or other documentation directly.
• User Guidance: While the skill automates detection and reporting, it relies on the user to make final decisions about how to update impacted ADRs.
• Allowed Tools: The skill leverages a specific set of tools (Read, Glob, Grep, Write, Bash, Task) for file operations, search, and scripting.

By integrating Propagate Design Change into your workflow, you can ensure architectural decisions remain up to date with evolving game designs, reducing risk and improving development velocity.